Developing a Circular-Economy-Based Construction Waste Minimisation Framework for Nigeria

A Thesis submitted in fulfilment of the requirements for the award of Doctor of Philosophy in Building

Olabode Emmanuel OGUNMAKINDE (M.Tech. & B.Tech. (Hons) Architecture, ND – Architectural Technology)

School of Architecture and Built Environment The University of Newcastle

May 2019

Declarations

Statement of Originality

I hereby certify that the work embodied in the thesis is my own work, conducted under normal supervision. The thesis contains no material which has been accepted, or is being examined, for the award of any other degree or diploma in any university or other tertiary institution and, to the best of my knowledge and belief, contains no material previously published or written by another person, expect where due reference has been made in the text. I give consent to the final version of my thesis being made available worldwide when deposited in the University’s Digital Repository**, subject to the provisions of Copyright Act 1968.

**Unless an Embargo has been approved for a determined period.

Signed…………………………………………………………………….

Date……………………………………………………………………….

Acknowledgement of Authorship

I hereby certify that the work embodied in this thesis contains published papers/scholarly work of which I am a joint author. I have included a written declaration below endorsed in writing by my supervisor, attesting to my contribution to the joint publication/scholarly work.

By signing below I confirm that Olabode Emmanuel Ogunmakinde contributed to research design, data collection, data analysis, and writing process of the papers/publications listed in this thesis.

…………………………… A/Prof. William Sher

Dedication

This thesis is dedicated to my wife, Oladoyin Ogunmakinde and my son, Oluwamurewa

Nathan Emmanuel (ONE) for their unflinching support, encouragement, and prayers.

Love you both!

Acknowledgments First and foremost, I would like to return the glory, honour, and adoration unto the Most High God, who has been my help and guide throughout the PhD journey. I am eternally grateful to my Lord and Saviour, Jesus Christ.

I would like to express my profound gratitude to the University of Newcastle for believing in my ability by offering me the UNIPRS and UNRCS 50:50 scholarships which covered my tuition and living expenses throughout my PhD study in Australia. I could not have achieved this milestone without the scholarships. I am also grateful to the management of Federal University of Technology Akure (FUTA), Nigeria for approving my study leave. I would like to extend my appreciation to the head and members of the department of Architecture, FUTA for their moral support.

I wish to thank many people who supported and contributed to the success of my doctoral study. My heartfelt appreciation goes to my supervisors, Associate Professor William Sher and Dr Kim Maund for their encouragement, continuous support, guidance, commitment, patience, immense knowledge, and inspiration throughout the research journey. Their constructive criticisms and feedback were of tremendous help throughout the time of research and writing of this thesis. Thank you for your interest in my research and for believing in my abilities. I could not have had better supervisors than the combination of Willy and Kim.

I would also like to thank Associate Professor Thayaparan Gajendran, Professor Peter Davis, Dr Jason Von Meding, Dr Ifte Ahmed, and Associate Professor Patrick Tang, for their insightful comments and questions that shaped my thoughts throughout the journey. I am also grateful to the entire SABE professional team for their continuous administrative support and assistance.

My sincere appreciation goes to Prof. Olu Ola Ogunsote, Dr Sue Sherratt, Dr Olatunji Oluwole, Dr Ernest Ekpo, Dr Rafiu Salami, Dr Rotimi Abidoye, Dr Michael Fayemiwo, Dr Ayokunle Olanipekun, and Victor Mogre for their motivation, moral support, and immense contributions at different stages of the data collection, analysis, and writing. To my friends and colleagues – Tijani Bashir, Arc. Daniel Akeremale, Olufemi Adetunji, Owi Toinpre, Reza Forghani, Matthew Abunyewah, Noah Mtembu, and Oluwadunsin Ajulo, thank you all for those stimulating discussions, conversations, and friendship.

iii

I am indebted to my spiritual fathers – Evangelist Bello, Revd. James Fatoye, Revd. Tunde Taiwo, and Pastor (Dr) and Pastor (Mrs) Kehinde Olatunbosun for their prayers, encouragement, and exhortations. I would like to thank all members of the Redeemed Christian Church of God, City of David Parish, Newcastle, especially the Davidic Praise Team members for their moral support and understanding while I was leading the group.

Finally, a very special thanks to my wife, Oladoyin Ogunmakinde and my son, Oluwamurewa Nathan Ogunmakinde for their love and patience while I was busy conducting this research. I would like to thank my parents, Mr Akinade Ogunmakinde and Mrs Christiana Ogunmakinde for their care, love, encouragement, and support throughout my academic career. I am also grateful to my siblings – Olukayode Ogunmakinde, Oladipupo Ogunmakinde, Oluwaseyi Adenola, and Olawumi Jones; and parents-in-law, Elder and Revd. Mrs Olajide for their encouragement and kindness towards me. Without the support of my uncles, aunts, cousins, nephews and nieces, it would not have been possible to complete this study. From the depth of my heart, I say thank you all.

Table of Contents

Declarations ...... i Dedication ...... ii Acknowledgments...... iii Table of Contents ...... v List of Figures ...... xi List of Tables ...... xiii List of Appendices ...... xv List of Abbreviations, Acronyms and Definition of Key Terms ...... xvi Publications ...... xix ABSTRACT ...... xx CHAPTER ONE - INTRODUCTION...... 1 1.0 Introduction ...... 1 1.1 Research Background ...... 1 1.2 Statement of the Research Problem ...... 4 1.3 Gaps in the Literature ...... 4 1.4 Research Question and Hypotheses ...... 6 1.5 Research Aim and Objectives ...... 9 1.6 Research Methodology ...... 9 1.7 Research Scope ...... 11 1.8 Contribution to Knowledge ...... 12 1.9 Limitations of the Study ...... 13 1.10 Thesis Structure ...... 14 1.11 Summary ...... 17 CHAPTER TWO - CONSTRUCTION WASTE MINIMISATION ...... 18 2.0 Chapter Overview ...... 18 2.1 Construction and Sustainable Development ...... 18 2.1.1 Sustainable Development ...... 18 2.1.2 Concept of Sustainability ...... 19 2.1.3 Construction ...... 19 2.1.4 Sustainable Construction (SC) ...... 21 2.2 Construction Waste ...... 24 2.2.1 Generation and Causes of Construction Waste ...... 25

2.2.2 Types of Construction Waste ...... 26 2.3 Construction Waste Minimisation ...... 27 2.3.1 Drivers of Construction Waste Minimisation ...... 33 2.3.2 Benefits of Construction Waste Minimisation ...... 33 2.3.3 Obstacles to Construction Waste Minimisation ...... 34 2.3.4 Framework for Construction Waste Minimisation ...... 36 2.3.5 Theory of Waste Behaviour (TWB) ...... 37 2.4 Nigerian Construction Industry ...... 39 2.4.1 Government Roles ...... 42 2.4.2 Demand and Supply ...... 42 2.4.3 Competition ...... 43 2.4.4 Construction Materials ...... 43 2.4.5 Construction Firm Sizes ...... 44 2.4.6 Skilled and Unskilled Construction Workforce...... 44 2.5 Opportunities for the Nigerian Construction Industry ...... 45 2.6 Challenges for the Nigerian Construction Industry ...... 46 2.7 Regulatory Frameworks in the Nigerian Construction Industry ...... 48 2.7.1 Development Control Agencies ...... 48 2.7.2 Government Ministries, Departments, and Agencies ...... 49 2.7.3 Professional Regulatory Bodies ...... 50 2.7.4 Construction Policies and Regulations ...... 50 2.8 Path to Sustainable Development ...... 53 2.8.1 Sustainable Development Goals ...... 53 2.8.2 Vision 20:2020 ...... 53 2.8.3 National Environmental Summit ...... 54 2.9 Summary ...... 54 CHAPTER THREE - THE CONCEPT OF CIRCULAR ECONOMIES ...... 56 3.0 Overview ...... 56 3.1 The Circular Economy Concept ...... 57 3.1.1 Origin of the Circular Economy ...... 57 3.1.2 Definition of the Circular Economy ...... 59 3.1.3 Principles of the Circular Economy...... 61 3.1.4 Characteristics of the Circular Economy ...... 65 3.2 Background of the Circular Economy ...... 69 3.2.1 Comparison of the CE’s Roots ...... 70

3.3 Transition to the Circular Economy ...... 74 3.3.1 Product Design ...... 75 3.3.2 Business Models of the Circular Economy ...... 76 3.3.3 Enabling Conditions ...... 81 3.3.4 Reverse Networks ...... 82 3.3.5 Top-down and Bottom-up Approaches ...... 82 3.3.6 Tools and Techniques ...... 83 3.4 Practical Applications and Implementation of the CE ...... 84 3.4.1 Implementation ...... 84 3.4.2 Policies, Models and Strategies ...... 85 3.5 Assessment of the CE ...... 89 3.5.1 Benefits of the Circular Economy ...... 89 3.5.2 Drivers of the CE ...... 90 3.5.3 Challenges of the CE ...... 93 3.5.4 Criticism of the CE ...... 96 3.6 CE and SD ...... 96 3.6.1 Environmental Impacts of the CE ...... 98 3.6.2 Economic Impacts of the CE ...... 99 3.6.3 Social Impacts of the CE ...... 101 3.6.4 Technological Impacts of the CE ...... 104 3.7 The CE and the Construction Industry ...... 104 3.7.1 Opportunities for Circularity in the Construction Industry ...... 105 3.7.2 Practical Approaches to the CE in the Construction Industry ...... 107 3.7.3 Practical Steps towards the CE ...... 112 3.8 Theoretical Perspective of the CE ...... 114 3.8.1 Diffusion of Innovations Theory ...... 114 3.9 Summary ...... 118 CHAPTER FOUR - RESEARCH METHODOLOGY ...... 120 4.0 Overview ...... 120 4.1 Research Paradigm ...... 122 4.2 Research Approach ...... 124 4.3 Mixed Methods ...... 125 4.4 Triangulation Design ...... 126 4.5 Quantitative Phase ...... 127 4.5.1 Unit of Analysis ...... 127

vii

4.5.2 Questionnaire Development ...... 127 4.5.3 Sampling ...... 129 4.5.4 Pre-Testing ...... 130 4.5.5 Data Collection ...... 130 4.5.6 Margin of Error ...... 131 4.5.7 Quantitative Data Analysis ...... 131 4.6 Qualitative Phase ...... 134 4.6.1 Target Respondents ...... 135 4.6.2 Structure of the Interview ...... 136 4.6.3 Pilot Survey ...... 137 4.6.4 Sample Size ...... 137 4.6.5 Protocol for Interview ...... 139 4.6.6 Project Characteristics and Response Rate ...... 140 4.6.7 Qualitative Data Analysis ...... 140 4.7 Validity, Reliability and Generalisability ...... 142 4.8 Data Merging ...... 143 4.9 Ethics Considerations ...... 144 4.10 Bias………………………………………………………………………………...145 4.11 Summary ...... 146 CHAPTER FIVE - INTEGRATED DATA ANALYSIS AND FINDINGS ...... 148 5.0 Overview ...... 148 5.1 Quantitative Results ...... 149 5.1.1 Response Rate ...... 149 5.1.2 Interpretation of Quantitative Results...... 150 5.1.3 Quantitative Responses ...... 154 5.1.4 Summary of Quantitative Results ...... 184 5.2 Qualitative Interpretation of Results ...... 184 5.2.1 Demographics ...... 185 5.2.2 Process of Data Analysis ...... 187 5.2.3 Analysis of Primary Data ...... 187 5.2.4 Summary of Qualitative Interpretation of Results ...... 222 CHAPTER SIX - DISCUSSION ...... 224 6.0 Overview ...... 224 6.1 Objective 1: To Identify the Types, Causes, and Disposal of Material Waste in the Nigerian Construction Industry ...... 225

viii

6.1.1 Types of Material Waste ...... 225 6.1.2 Causes of Material Waste ...... 226 6.1.3 Method of Material Waste Disposal ...... 229 6.2 Objective 2: To Investigate the Awareness, Attitudes, and Perceptions of the NBCFs to Material Waste Minimisation ...... 231 6.2.1 Awareness of the Effects of Material Wastages ...... 231 6.2.2 Attitudes of NBCFs towards Material Waste Minimisation ...... 233 6.2.3 Perceptions of NBCFs on Material Waste Minimisation ...... 234 6.2.4 Relationship between Awareness, Attitudes, and Perceptions ...... 236 6.3 Objective 3: To Investigate Current Approaches Adopted by the NBCFs to Minimise Material Waste at Design, Procurement, and Construction Phases ...... 237 6.3.1 Design Approaches Implemented in Practice by the NBCFs ...... 237 6.3.2 Procurement Approaches Implemented in Practice by the NBCFs ...... 239 6.3.3 Sustainable Construction Approaches Implemented by the NBCFs ...... 241 6.3.4 Relationship between Waste Minimisation Approaches and Company Characteristics ...... 244 6.4 Objective 4: To Investigate the Extent of Adoption of the 3R Principle by the NBCFs ...... 245 6.5 Objective 5: To Identify Policies and/or Legislative Measures for Waste Minimisation and Implementation Methods that are Appropriate for the Nigerian Construction Industry ...... 248 6.5.1 Policies and Legislative Measures to Waste Minimisation ...... 248 6.5.2 Waste Minimisation Implementation Strategies ...... 250 6.6 Objective 6: To Investigate the Readiness of the Nigerian Construction Industry to Adopt a Circular-Economy-Based Waste Minimisation Framework ...... 252 6.6.1 Existing Organisational Policies on Waste Minimisation ...... 252 6.6.2 Willingness to Adopt New Waste Minimisation Method ...... 252 6.7 The CE-Based Construction Waste Minimisation Framework (CE-CWMF) ...... 253 6.7.1 Introduction to the CE-CWMF guideline ...... 254 6.7.2 Composition of the CE-CWMF guideline ...... 257 6.8 Summary of Key Findings and their Implications ...... 264 CHAPTER SEVEN - CONCLUSION AND RECOMMENDATIONS ...... 269 7.0 Overview ...... 269 7.1 Key Findings of the Study ...... 270 7.2 Contributions to Knowledge ...... 276 7.2.1 Implications for Practice ...... 276 7.2.2 Theoretical Implications ...... 279

7.3 Recommendations ...... 281 7.3.1 Recommendations for Policy ...... 281 7.3.2 Recommendations for Training and Education ...... 282 7.3.3 Recommendations for Change in Organisational Culture and Attitude .... 282 7.3.4 Recommendations for Best Practices ...... 283 7.3.5 Recommendations for Research and Development in the NCI ...... 283 7.4 Future Research Directions ...... 284 7.5 Concluding Remarks ...... 285 References ...... 286 Appendices ...... 337

List of Figures Figure 1.1: Research methodology flowchart ...... 15 Figure 1.1: Thesis layout...... 15 Figure 2.1: Overview of the construction industry ...... 20 Figure 2.2: Relationship between SD, SC and Sustainability ...... 22 Figure 2.3: Framework for the relationship between SC and Construction phases ...... 24 Figure 2.4: Sectoral contributions to real GDP in Nigeria (2017) ...... 39 Figure 2.5: Nigerian construction sector’s contribution to real growth ...... 40 Figure 2.6: Nigerian construction industry and construction waste minimisation ...... 45 Figure 2.7: Nigeria’s GDP from construction...... 45 Figure 2.8: Challenges for the NCI...... 47 Figure 3.1: Chronological order of the CE origin ...... 59 Figure 3.2: The CE principles ...... 63 Figure 3.3: Overview of the CE ...... 68 Figure 3.4: CE roots ...... 69 Figure 3.5: CE framework ...... 70 Figure 3.6: CE policies ...... 85 Figure 3.7: Eco design categories ...... 88 Figure 3.8: Diffusion of Innovation model ...... 116 Figure 3.9: Modified innovation-decision process ...... 117 Figure 4.1: Summary of the research design ...... 121 Figure 4.2: Research sequence ...... 125 Figure 4.3: Logic of inductive and deductive reasoning ...... 125 Figure 4.4: Triangulation ...... 126 Figure 4.5: Concurrent triangulation design ...... 126 Figure 4.6: Convergent parallel design ...... 144 Figure 5.1: Outline of chapter five ...... 149 Figure 5.2: Scree plot – Design Approaches ...... 168 Figure 5.3: Scree plot - Procurement Approaches ...... 171 Figure 5.4: Scree plot of sustainable construction approaches ...... 174 Figure 5.5: Scree plot of the 3R approaches ...... 178 Figure 5.6: Graphical representation of NBCFs’ waste minimisation policy ...... 183 Figure 5.7: Graphical representation of NBCFs’ willingness to adopt new construction waste minimisation method ...... 183 Figure 5.8: Map of Lagos showing project location marked in red ...... 186 Figure 5.9: Picture of wood waste on S7 ...... 188 Figure 5.10: Picture of cement packaging waste on S6 ...... 188 Figure 5.11: Picture of wood waste on S6 ...... 188 Figure 5.12: Graphical representation of the causes of waste ...... 190 Figure 5.13: Graphical representation of waste disposal methods ...... 194 Figure 5.14: Picture showing evidence of burning on S7 ...... 195 Figure 5.15: Graphical representation of the effects of material waste ...... 197 Figure 5.16: Graphical representation of interviewees’ attitudes to waste minimisation ...... 199 Figure 5.17: Graphical representation of NBCFs’ perception of waste minimisation ...... 200 Figure 5.18: Paladina floor ...... 209

Figure 5.19: Graphical representation of the availability of written plan or policy on construction waste minimisation ...... 221 Figure 6.1: Relationship between NBCFs’ awareness, attitudes and perceptions ...... 236 Figure 6.2: Proposed Circular Economy Construction Waste Minimisation Framework…..256

xii

List of Tables Table 1.1: Research Questions and Hypotheses ...... 7 Table 1.2: Relationship between research sub-question, objectives and methods ...... 11 Table 2.1: Relationship between SC and Construction phases ...... 23 Table 2.2: Significant factors contributing to construction waste ...... 25 Table 2.3: Legislative measures for waste minimisation ...... 32 Table 2.4: Drivers of sustainable waste management ...... 33 Table 2.5: Firm size distribution in Nigeria ...... 44 Table 2.6: Ongoing mega construction projects in Nigeria ...... 46 Table 2.7: Federal Ministries and their responsibilities ...... 49 Table 2.8: Sections of the National Building Code ...... 51 Table 3.1: Definitions of the CE ...... 60 Table 3.2: Descriptions of the CE in literature ...... 61 Table 3.3: Characteristics of the CE ...... 66 Table 3.4: Comparison of the CE roots ...... 72 Table 3.5: ReSOLVE Framework ...... 81 Table 3.6: Drivers of CE ...... 91 Table 3.7: Economic, Social and Environmental programmes in Nigeria ...... 93 Table 3.8: Barriers of the CE ...... 94 Table 3.9: Similarities between CE and Sustainability ...... 97 Table 3.10: Environmental impacts of the CE ...... 99 Table 3.11: The CE network ...... 113 Table 4.1: Logical relationship between research paradigm, methods and design ...... 123 Table 4.2: Target respondents, their characteristics and codes ...... 136 Table 4.3: Structure of the interview guide ...... 137 Table 4.4: Approaches to qualitative sampling ...... 138 Table 4.5: Interview sample size ...... 138 Table 4.6: Project characteristics ...... 140 Table 4.7: Potential bias and minimisation strategies ...... 145 Table 4.8: Summary of the research methodology process ...... 146 Table 5.1: Main survey response rate ...... 150 Table 5.2: Terms used to describe percentage ranges ...... 150 Table 5.3: Respondents characteristics ...... 152 Table 5.4: Organisations’ characteristics ...... 153 Table 5.5: Types of material waste generated by the NBCFs ...... 154 Table 5.6: Friedman test statistics for material waste ...... 155 Table 5.7: Design causes of material waste ...... 155 Table 5.8: Causes of material waste at the procurement phase ...... 156 Table 5.9: Causes of material waste at the construction phase ...... 156 Table 5.10: Method of material waste disposal ...... 157 Table 5.11: Relative importance index of NBCFs’ awareness ...... 158 Table 5.12: Relative importance index of NBCFs’ attitude ...... 159 Table 5.13: Relative importance index of NBCFs’ perception ...... 160 Table 5.14: Spearman rho correlation matrix ...... 163 Table 5.15: Design approaches to material waste minimisation ...... 164 Table 5.16: Categories of design approaches to material waste minimisation…………..…….. 165

xiii

Table 5.17: Rotated Component Matrix ...... 166 Table 5.18: Procurement approaches to material waste minimisation ...... 168 Table 5.19: Rotated Component Matrix—Procurement Approaches ...... 170 Table 5.20: Sustainable construction approaches to material waste minimisation ...... 171 Table 5.21: Rotated Component Matrix—Sustainable Construction Approaches ...... 173 Table 5.22: Kruskal Wallis Test for waste minimisation approaches and company ownership status ...... 175 Table 5.23: Kruskal Wallis Test for waste minimisation approaches and company size ...... 175 Table 5.24: Kruskal Wallis Test for waste minimisation approaches and company age ...... 176 Table 5.25: Kruskal Wallis Test for waste minimisation approaches and company's main construction activity ...... 176 Table 5.26: The 3R approaches to material waste minimisation ...... 177 Table 5.27: Rotated component matrix of the 3R approaches ...... 179 Table 5.28: Waste minimisation policies/measures ...... 180 Table 5.29: Rotated component matrix of waste minimisation policies ...... 181 Table 5.30: Waste minimisation implementation and Friedman test statistics ...... 182 Table 5.31: Demography of interviewees ...... 185 Table 5.32: Project characteristics ...... 186 Table 5.33: Causes of material waste ...... 189 Table 5.34: Waste disposal methods ...... 193 Table 5.35: Effects of material waste ...... 196 Table 5.36: Perception of the NBCFs on the importance of waste minimisation ...... 198 Table 5.37: Strategies for waste minimisation ...... 211 Table 5.38: Implementation methods for waste minimisation strategies ...... 215 Table 5.39: Proposed training focus for construction firms ...... 217 Table 6.1: Synthesis of types of material waste ...... 225 Table 6.2: Synthesis of causes of material waste ...... 226 Table 6.3: Synthesis of methods of material waste disposal ...... 230 Table 6.4: Synthesis of the effects of material wastage ...... 231 Table 6.5: Synthesis of attitudes towards waste minimisation ...... 233 Table 6.6: Synthesis of perceptions on material waste minimisation ...... 235 Table 6.7: Synthesis of design approaches to waste minimisation ...... 237 Table 6.8: Synthesis of procurement approaches to waste minimisation ...... 240 Table 6.9: Synthesis of construction approaches to waste minimisation ...... 242 Table 6.10: Synthesis of the 3R principle to waste minimisation ...... 245 Table 6.11: Synthesis of policies/legislative measures for waste minimisation ...... 248 Table 6.12: Waste minimisation implementation strategies ...... 250 Table 6.13: Proposed CE-CWMF guideline ...... 253 Table 6.14: Proposed major policy directions ...... 263 Table 6.15: Summary of key findings …………………………………………………………………….264 Table 7.1: Research objectives ...... 269 Table 7.2: Sustainable development goals achieved ...... 280

xiv

List of Appendices Appendix A: Website of Lagos State Government Building Control Agency ...... 337 Appendix B: Design Approaches for Minimising Waste ...... 338 Appendix C: Procurement Approaches for Minimising Waste ...... 342 Appendix D: Construction approaches to minimising waste ...... 344 Appendix E: Email Correspondence from Corporate Affairs Commission ...... 348 Appendix F: Survey Questionnaire ...... 349 Appendix G: Cover Letter for Online Survey Request ...... 359 Appendix H: Reminder Letter for Online Survey Request ...... 360 Appendix I: Interview Guide ...... 361 Appendix J1: Information Statement for Organisations (Interviews) ...... 363 Appendix J2: Information Statement for Interviewees ...... 367 Appendix K1: Consent Form for Organisations ...... 370 Appendix K2: Consent Form for Interviewees ...... 371 Appendix L: Information Statement for Organisations (Questionnaire) ...... 372 Appendix M: Human Research Ethics Approval ...... 376 Appendix N: Overall causes of material waste ...... 379 Appendix O: Correlation Matrix of Design Approaches ...... 380 Appendix P: Correlation Matrix of Procurement Approaches ...... 387 Appendix Q: Correlation Matrix of Sustainable Construction Approaches ...... 391 Appendix R: Correlation Matrix of 3R Approaches ...... 395 Appendix S: Correlation Matrix of Waste Minimisation Policies/Measures ...... 398

List of Abbreviations, Acronyms and Definition of Key Terms 3R Reduce, Reuse, and Recycle B2B Business to Business BIM Building Information Modelling BM Business Models C&D Construction and Demolition C2C Cradle to Cradle CE Circular Economy CE-CWM Circular Economy - Construction Waste Minimisation CPD Continuous Professional Development CWDCS Construction Waste Disposal Charging Scheme DEFRA Department for Environment, Food and Rural Affairs DfDF Design for Deconstruction and Flexibility DfMO Design for Material Optimisation DfOC Design for Off-site Construction DfRR Design for Reuse and Recycle DfWEP Design for Waste Efficient Procurement DOI Diffusion of Innovation EAA European Environment Agency EC European Commission EFA Exploratory Factor Analysis EIA Environmental Impact Assessment EPA Environmental Protection Agency EPR Extended Producer Responsibility EU European Union GDP Gross Domestic Product HND Higher National Diploma HSE Health Safety and Environment ICT Information Communication Technology IoT Internet of Things

xvi

IPD Integrated Project Design ISO International Standard Organisation JIT Just-in-Time KMO Kaiser-Meyer-Olkin LASBCA Lagos State Building Control Agency LAWMA Lagos State Waste Management Authority LCA Life Cycle Analysis LCC Life Cycle Costing MFA Material Flow Analysis NBCFs Nigerian Building Construction Firms NCI Nigerian Construction Industry NDRC National Development and Reform Commission NEMA National Emergency Management Agency NESREA National Environmental Standards and Regulations Enforcement Agency NIOB Nigerian Institute of Building OECD Organisation for Economic Co-operation and Development OND Ordinary National Diploma PaaS Product as a Service PAYT Pay As You Throw PCA Principal Component Analysis PLC Public Limited Company QDA Qualitative Data Analysis RFID Radio Frequency Identification RII Relative Importance Index RL Reverse Logistics RQ Research Question SC Sustainable Construction SD Sustainable Development SIS Stepwise Incentives Scheme SON Standard Organisation of Nigeria

xvii

SPSS Statistical Package for the Social Sciences SWM Sustainable Waste Management SWMP Site Waste Management Planning TOPREC Town Planners Registration Council UK United Kingdom UNEP United Nations Environment Programme WEF World Economic Forum WM Waste Management WRAP Waste and Resources Action Programme WTP Willingness to Pay

Definition of Key Terms Circular economy: A sustainable concept that ensures zero waste of materials, low pressure on resource consumption and energy through reuse and recycling principles. It is a waste reduction system that maximises materials and products. Construction waste management: A set of methods and procedures for managing the volume of waste after it is generated. Construction waste minimisation: A set of methods and procedures for reducing the volume waste before it is generated. Construction waste: A waste stream produced by construction activities. Disposal: The collection, storage and/or destruction of unwanted materials and products. Landfill: A waste disposal site where waste of all kinds is buried. Pollution: The introduction of a substance that has harmful effects into the environment. Recycling: The transformation of previously used materials into new products to decrease extraction of raw materials. Resource efficiency: An efficient use of natural resources to derive their greatest value. Reuse: A process where materials and products from the waste stream are used for their original purposes again. Zero waste: A concept which promotes the reduction, reuse and recycling of waste to prevent sending materials and products to landfill.

xviii

Publications Ogunmakinde, O.E. (2019). A Review of Circular Economy Development Models in China, Germany and Japan. Recycling, 4(3), 27. https://doi.org/10.3390/recycling4030027 Ogunmakinde, O.E., Sher, W.D., & Maund, K. (2019). An Assessment of Material Waste Disposal Methods in the Nigerian Construction Industry. Recycling 4(1), 13; doi: 10.3390/recycling4010013. https://www.mdpi.com/2313-4321/4/1/13/pdf Ogunmakinde, O.E., Sher, W.D., & Maund, K. (2019) Challenges of the Nigerian Construction Industry: A Systematic Review. In: Proceedings of iiSBE Forum of Young Researchers in Sustainable Building 2019. 1 July, Prague, Czech Republic. Ogunmakinde, O.E., Sher, W.D., & Maund, K. (2019) Responsibility for minimising construction material wastes. In: Proceedings of the 2019 University of Maryland Project Management Symposium, 9 – 10 May, Maryland, USA.

Ogunmakinde, O.E., & Umeh, S. (2018) Adoption of BIM in the Nigerian Architecture Engineering and Construction (AEC) Industry. In: proceedings of the 42nd Australasian Universities Building Education Association (AUBEA) Conference, 26 – 28 September, Singapore. ISBN: 978-0-9871831-3-2 (Print) & ISBN 978-0-9871831-6-3 (e-Book)

Ogunmakinde, O.E., Sher, W.D., Ogunmakinde, O.O., & Ayanniyi, O.I. (2017) Factors Affecting Construction Students’ Satisfaction with Grades in Design Courses. In: Proceedings of the 41st Australasian Universities Building Education Association (AUBEA) Conference, 3 – 5 July, Melbourne, Australia, 713 – 722.

Ogunmakinde, O.E., Sher, W.D., & Maund, K. (2017) Exploring the relationship between Construction Phases and Sustainable Construction Principles. In: Proceedings of the 2017 World Sustainable Built Environment, 5 – 7 June, Wan Chai, Hong Kong. 2771 – 2778. ISBN: 978-988-77943-0-1

Ogunmakinde, O.E., Sher, W.D., & Maund, K. (2017) Circular Construction: Opportunities and Threats. In: Proceedings of the 2017 University of Maryland Project Management Symposium, 4 – 5 May, Maryland, USA. ISSN: 2374-9377.

Ogunmakinde, O.E., Sher, W.D., & Maund, K. (2016) Construction Professionals’ Perceptions of Sustainability in Developing Countries. In: Proceedings of the 40th Australasian Universities Building Education Association (AUBEA) Conference, 6 – 8 July, Cairns, Australia. ISBN: 978-1-921047-13-8

Ogunmakinde, O.E., Sher, W.D., & Maund, K. (2016) Obstacles to Sustainable Construction in Developing Countries. In: Proceedings of the 40th Australasian Universities Building Education Association (AUBEA) Conference, 6 – 8 July, Cairns, Australia. ISBN: 978-1- 921047-13-8

xix

ABSTRACT The construction industry plays a significant role in developing and developed nation’s growth. It has been criticised as unsustainable because it impacts negatively on the environment and makes onerous demands on natural resources. Therefore researchers, policy makers, governments and non-governmental organisations have recognised the need to promote sustainable construction. Nigeria, one of Africa’s fastest-growing economies and the most populous, is endeavouring to implement sustainable practices. Its construction industry is viewed as lacking sustainable construction approaches such as waste management. The industry is heavily dependent on natural resources and its activities contribute to environmental degradation. A number of studies have identified high volumes of waste and this has highlighted the need for alternative approaches to the current traditional method of construction linked to the linear economy. The circular economy is a concept that integrates material repair, reduction, reuse, and recycling. Although the circular economy has not been applied in Nigeria, it has been adopted in the manufacturing, steel, and agricultural sectors in countries like China, Scotland, and Finland, while others are considering its adoption. The circular economy requires a holistic approach to be effectively and efficiently mainstreamed. Despite its advantages, there has been little investigation of its adoption for the Nigerian construction industry. The aim of this study is to develop a circular-economy-based construction material waste minimisation framework for Nigeria with a view to achieving sustainable construction.

The objectives are, first, to identify types, causes, and methods of disposal for material waste. Second, to investigate the awareness, attitudes, and perceptions of Nigerian building construction firms to material waste minimisation. Third, to investigate current approaches to material waste minimisation at the design, procurement, and construction phases. Fourth, to investigate the extent to which the 3R principle has been adopted. Fifth, to identify policies or legislative measures and implementation methods for waste minimisation. Finally, to develop a circular-economy-based construction waste minimisation framework and investigate readiness for its adoption by Nigerian building construction firms. This study is founded on literature about construction waste management, the Nigerian construction industry, construction processes and phases as well as sustainable construction. The concept of the circular economy, including its origins, definitions, principles, characteristics, approaches, drivers, challenges, and benefits have been reviewed. The foundations of the circular economy and theoretical perspectives underpinning its integration have also been reviewed.

This study has been viewed from a pragmatic philosophical stance that encourages the use of methods appropriate for the problem. A convergent parallel mixed methods approach was employed to obtain primary data from building construction firms in Lagos, Nigeria. Using a concurrent triangulation design, data obtained from a questionnaire survey were triangulated with data from semi-structured interviews and direct observation. Secondary data were collected via a traditional literature review. Quantitative data were analysed using SPSS. The tests conducted are the relative importance index analysis, factor analysis, Kruskal-Wallis test, and the Spearman’s rank correlation. Qualitative data were analysed through thematic analysis using NVivo 11 to identify key themes, relationships, coding, and sorting into categories. To ensure reliability and validity of the questionnaire data, a Cronbach’s Alpha test was conducted, with a result of 0.83 indicating good reliability and validity. A rigorous process, including a review of the research problem, design, and interview questions, as well as six rechecks of interview transcripts, ensured reliability and generalisability of the qualitative data.

Findings suggest that concrete, timber products, and offcut tiles are the main types of waste generated in the Nigerian construction industry. The causes of these types of waste at the design, procurement, and construction phases are design changes, substandard materials, and quality of supervision, respectively. Nigerian building construction firms demonstrate a high level of awareness of the effects of material waste, while exhibiting positive attitudes to waste minimisation. However, their perceptions vary, although the majority perceived environmental protection as an important factor for waste minimisation. The relationships between the Nigerian building construction firms’ awareness, attitudes, and perceptions indicate that these are influenced by their perceptions. Furthermore, the study reveals that design for material optimisation is the design approach most frequently embraced to minimise waste, while design for reuse and recycling is the least frequently used. The most significant procurement approach adopted by the Nigerian building construction firms is to purchase durable materials. A factor analysis of procurement approaches was conducted, and two factors labelled “act green” and “buy green” were extracted. For construction approaches, stock control, effective team work, and avoiding excavation of unnecessary soil were identified as the most important processes, while factor analysis of construction approaches yielded three factors, namely: strategies, techniques, and operations. These approaches to waste minimisation differ among medium and large-scale construction companies.

Additionally, the research has revealed reuse of formwork and scaffolding as the most significant approach of the 3Rs principle (reduce, reuse, and recycle). A factor analysis of the

xxi

3Rs approaches to waste minimisation yielded three factors, labelled “reduce”, “reuse”, and “recycle”. Site waste management planning is considered by Nigerian building construction firms as the most important policy to minimise waste. Two factors labelled “recommended” and “required” policies were extracted from the factor analysis of policies and regulations for ease of description and understanding. The key implementation methods are policy and education/training of the construction workforce. However, more than half of the firms surveyed do not have an organisational policy on waste minimisation, while 89.3% were keen to adopt a new waste minimisation method. Following these findings, a circular-economy- based construction waste minimisation framework was developed based on the diffusion of innovation theory. The framework consists of five sections, which are: identification of waste minimisation needs, assessment of existing minimisation measures, policy identification and formulation, identification of implementation methods, and evaluation of the proposed framework.

This study has established a framework that can be used as a baseline for waste minimisation in the Nigerian construction industry while contributing to gaps identified in the body of knowledge. Adoption of the framework by Nigerian building construction firms and the Nigerian construction industry in general has the potential to reduce waste generated and landfilled. Recommendations are made for policy, training and education, changes in organisational culture and attitudes, best practices, and research and development. The study concludes by identifying future research areas.

xxii

CHAPTER ONE INTRODUCTION 1.0 Introduction Construction waste has become an environmental health issue that needs to be addressed. Chapter one provides background information about the challenges associated with construction material waste minimisation in Nigeria. It introduces the circular economy (CE) as a potential method for construction waste minimisation in the Nigerian construction industry (NCI). The chapter also highlights the advantages of the CE over the linear economy (the traditional construction method). Deficiencies in the literature of construction waste minimisation in the NCI, and the aim and objectives to address these gaps, are presented. A synopsis of the research methodology, contribution to knowledge, and limitations of the study are provided. The contributions to practice and policies are also presented. Limitations are explored and a concise description of the overall structure of the thesis is provided.

1.1 Research Background Rapid developments worldwide, including economic growth, urbanisation, and technology, have occurred in the aftermath of the industrial revolution of the 18th and 19th centuries (Allen, 2009; Griffin, 2013). This period witnessed a transition from crude to sophisticated manufacturing processes and methods, involving the use of new materials, energy sources and machines. These rapid developments were accompanied by the heavy use of natural resources for mass production, which has had detrimental consequences (Mantoux, 2013). Ecological destruction and resource depletion have been identified as major environmental consequences of these developments (Song, Li, & Zeng, 2015; Vieira & Pereira, 2015; Menikpura, Gheewala, Bonnet, & Chiemchaisri, 2013; Plagányi et al., 2013; Huang, 2012; Zhu, Geng, & Lai, 2010 Yuan, Bi, & Moriguichi, 2006). Although environmental issues have received unabated attention globally from governmental and non-governmental organisations, they have been difficult to mitigate due to their interrelationships (Pereira, 2015). The World Bank (2012) estimates that municipal solid waste could increase by 900 million tonnes by 2025 as a result of increased global population. This suggests an increase in environmental pollution and emphasises the need for interventions to reduce waste.

Rapid urbanisation in developing countries like those in Asia and Africa accounts for the infrastructural growth. As one of the largest contributors to such developments, waste from the construction industry impacts the environment negatively (Abidin, 2010; Dania, Kehinde, &

Bala, 2007). High volumes of waste are associated with pollution, climate change and resource depletion (Ameh & Itodo, 2013; Du Plessis, 2002; Ofori, 2000). For example, the European Commission reported in 2001 that the construction industry consumes 50% of natural resources and energy annually.

According to Eurostat (2014), waste resulting from economic activities in Europe accounted for 33.5% in 2014, which is one-third of total waste generated that year. In the same year, the US generated 40% of solid waste from the construction industry. In Australia, the industry was responsible for 30.7% of the total 53.7 million tonnes accrued in 2009 and 2010 (Australian Bureau of Statistics, 2013), while in Finland it accounted for about 13.8 million tonnes of waste generated in 2016 (OSF, 2018). These high volumes of waste generated across the world highlight the need for waste minimisation strategies. Although there is potential to minimise construction waste (European Commission, 2001), less than one-third is reused and recycled (WEF, 2016) and a considerable amount is landfilled. For example, 29% of construction waste is landfilled in the UK, 54% in Finland, 44% in Australia, and 35% around the world (Arponen, Granskog, & Panstar, 2015; Oyedele, Kadiri, & Ajayi, 2014; DEFRA, 2013; Solís-Guzmán, Marrero, Montes-Delgado, & Ramírez-de-Arellano, 2009). Similarly, 27% of construction waste in landfilled in Hong Kong (Environmental Protection Department, 2018). Landfills produce leachate and greenhouse gases (e.g. carbon dioxide and methane), which contaminate groundwater and cause pollution, respectively (Danthurebandara, Van Passel, Nelen, Tielemans, & Van Acker, 2012). These negative effects highlight the need to reduce the waste that goes into landfills.

Sustainable construction (SC) seeks to meet current construction demands without endangering the capacity to respond to future demands (Pearce, 2005). One approach to SC is waste management, which offers economic benefits (such as cost savings (Oyenuga & Bhamidimarri, 2015), job creation, and reduced material prices (WRAP, 2007a) and environmental sustainability (Yuan, 2013). As a result, waste management measures have been developed (Ajayi et al., 2017; Wang, Wang, Liu, Fu, & Liu, 2014; Osmani, Glass, & Price, 2008; Dainty & Brooke, 2004). To promote SC, industry, government, and policy makers have enacted policies and legislation. These include construction waste disposal charging schemes, pay-as- you-throw schemes, stepwise incentive systems, landfill bans, and extended producer responsibility (Dahlén & Lagerkvist, 2010; WRAP 2007b/2009; Hao, Hills & Tam, 2008; Tam & Tam, 2008; OECD, 2001). Most of these measures have focused on managing waste after it has been generated, rather than the waste that is generated at each stage of construction. The

2 need for a holistic approach to waste minimisation has been emphasised in the literature but has not been well-explored.

Current traditional methods of construction are likened to a linear economy model that ‘takes- makes-uses-disposes’ (Jackson, Lederwasch, & Giurco, 2014; McDonough & Braungart, 2002). Natural resources are extracted (i.e. ‘take’) to manufacture (i.e. ‘make’) products (i.e. ‘use’) which are then disposed of. This implies that materials are disposed of either during the construction process or at the end of their useful lives (demolition). The raw materials utilised in manufacturing products are thus not recovered (Ellen MacArthur Foundation, 2013a). Consequently, materials disposed of at their end of life end up in landfill. A slow shift towards modern methods of construction is apparent across developed countries, including the UK, Finland, Sweden, and Australia (Koutsogiannis, 2018; Stocks, 2018; Elnaas, Gidado, & Philip, 2014; Sardén & Engström, 2010, Fussell et al., 2007), but many developing countries are lagging behind (Rahimian et al., 2017; Nadim & Goulding, 2010). Approaches that reduce resource consumption, reuse materials, recycle waste, and conserve energy are encouraged, and the circular economy (CE) is one such approach.

The CE has been proposed as a sustainable development (SD) concept to mitigate unsustainable consumption and production. It has the ability to restore and regenerate products through design and intention (Qian & Wang, 2016; Andrews, 2015; Murray, Skene, & Haynes, 2017; Su, Heshmati, Geng, & Yu, 2013; Si-yuan & Yuan, 2012; Dorn, Nelles, & Flamme, 2010). Kenneth E. Boulding described a circular or cyclic economy as closed-loop material usage (Greyson, 2007). The CE implies “resource-product-waste-regenerate resource” (Guohui & Yunfeng, 2012) and is a feasible substitute for the linear economy (which “takes-makes-uses- disposes”). The CE reduces pollution and conserves and minimises waste (Li, 2012; Shi, Xing, Bi, & Zhang, 2006). It focuses on conservation of existing products through re-use and recycling rather than new production (Löfgren & Enocson, 2014). The CE concept is exclusively elucidated in chapter three.

Transitioning to the CE requires a holistic approach, starting from the design of products, to adopting contemporary business models, to embracing innovative consumer consumption models (Smol, Kulczycka, Henclik, Gorazda, & Wzorek, 2015). The CE may apply to all industries, especially those engaged in production (including the construction industry). The potential of the CE to contribute to SC is substantial. It presents opportunities to reduce toxins, emissions, and pollution, limits the extraction of finite raw materials, and reduces material

wastage (Andrews, 2015; Moreno, Braithwaite, & Cooper, 2015; Persson, 2015; Geng, Fu, Sarkis, & Xue, 2012). While these opportunities are being explored in developed countries, there is limited evidence of their adoption in developing countries. For example, there is a paucity of data on the CE in Nigeria and its impact on reducing waste in the construction industry. It is therefore important to develop a CE framework for waste minimisation in the NCI. The applicability of the benefits reported for developed countries need to be explored for developing countries.

1.2 Statement of the Research Problem The United Nations (2015a) projected an increase of 2.4 billion in global population by 2050 and 3.9 billion by 2100. A large percentage of this increase will occur in developing countries. For example, Nigeria’s population grew by 14 million between 2015 and 2018 (World Bank, 2018b) increasing the demand for housing and infrastructure. The Nigerian building construction industry is projected to grow according to the country’s population (National Bureau of Statistics, 2018), and generate increasing amounts of waste. Currently, Nigerian building construction firms (NBCFs) generate more waste than is bid for (5–10%) in the bill of quantities (Oladiran, 2018; Adewuyi, Idoro & Ikpo, 2014). Despite the high percentage of waste on Nigerian construction sites, there are no effective strategies to mitigate construction waste.

There are also concerns that Nigeria faces numerous construction waste minimisation challenges: firstly, there is a lack of waste minimisation policies and exposure to SC concepts (Nwokoro & Onukwube, 2015); secondly, there is also negligence in incorporating sustainable concepts into building construction (Dania, Larsen, & Yao, 2013). These challenges have been shown to contribute to environmental degradation (Somorin, Adesola, & Kolawole, 2017). The limitations and concerns detailed above underscore the need for a waste minimisation policy and effective strategies to mitigate construction waste in the NCI. Prior to this, it is important that the causal factors for construction waste in the NCI are identified and remedied if we are to develop an informed and effective waste minimisation policies and strategies, however this is poorly understood.

1.3 Gaps in the Literature The causes, types, effects, and management strategies for construction waste in Nigeria have been studied (see Adewuyi & Odesola, 2015; Adewuyi & Otali, 2013; Ameh & Itodo, 2013; Odusami, Oladiran, & Ibrahim, 2012; Adafin, Daramola, & Ayodele, 2010; Eze, Seghosime,

Eyong, & Loya, 2017). Waste management often results from the need to clean up after waste has been generated. Construction waste management is generally poor in Nigeria because there is limited provision for it (Akinkurolere & Franklin, 2005; Oladiran, 2008, 2009a; Dania et al., 2007). To overcome waste management challenges, it is important to minimise the large volume of construction waste generated. However, there are few or no strategies for effective waste minimisation.

Globally, previous studies (Al-Hajj & Hamani, 2011; Kofoworola & Gheewala, 2009; Esin & Cosgun, 2007) have successfully identified the causes and impact of construction waste at various phases of the construction process. These studies have also identified approaches for minimising waste at either design, procurement or construction phases. However, a holistic approach to waste minimisation at all phases has not yet been developed. For example, WRAP (2009a, 2010a) and Sassi and Thompson (1998) have provided strategies associated with the reuse and recycling of waste. These management measures are aimed at reducing the waste sent to landfill but do not minimise waste at source. Other studies have identified various waste minimisation approaches but only at the design and procurement phases (Wang, Li, & Tam, 2014; Osmani et al., 2008; Dainty & Brooke, 2004). However, there is currently no comprehensive waste minimisation model encompassing all phases of construction. There is a need to close this gap so that effective strategies can be developed to minimise construction waste.

Studies that have investigated attitudes, perceptions, and behaviour of construction professionals to waste management and SC (Li, Tam, Zuo, & Zhu, 2015; Emmanuel, Ibrahim, & Adogbo, 2014; Al-sari, Al-Khatib, Ayraamides, & Fatta-Kassinos, 2012; Begum, Siwar, Pereira, & Jaafar, 2009) have focused on one or more construction profession in a single inquiry. For example, Li et al. (2015) studied designers’ attitudes and behaviours to waste minimisation. Likewise, Al-sari et al. (2012) focused on contractors’ attitudes and behaviour toward waste management. These studies have successfully identified behaviours relating to waste management. However, organisational behaviour to waste minimisation is poorly explored. In particular, there is little empirical evidence about organisational behaviour in relation to construction material waste minimisation in Nigeria.

Studies that have investigated the CE and its application (particularly in the manufacturing and steel industries) have achieved significant results in reducing waste and resource extraction (Ghisellini, Cialani, & Ulgiati, 2016; Moreno et al., 2015; Murray et al., 2017; Shi et al., 2006).

However, at the time of writing, no work has explored the concept of CE in the construction industry, despite it being identified as a sustainable concept (Guohui & Yunfeng, 2012; Jun & Xiang, 2011; Li, 2012; Murray et al., 2017; Qian & Wang, 2016; Si-yuan & Yuan, 2012) in many industries. The reasons for this need to be explored.

Generally, the CE has not been trialled as a waste minimisation strategy in the construction industry, even though it has been shown to be effective for reducing waste in other industries. There is a need to close this gap so that an effective, efficient, and holistic construction material waste minimisation framework can be developed.

1.4 Research Question and Hypotheses Literature shows that no holistic waste minimisation framework currently exists, and that construction firms generate more waste than is bid for in the bill of quantities (Emmanuel et al., 2014; Dania et al., 2007). Furthermore, the potential of the CE in the construction industry to achieve SC through waste minimisation is unknown. It is against these backdrops that this study seeks to answer the question:

‘How can construction material waste in the NCI be minimised using the circular economy concept?

Table 1.1 details the hypotheses that have been postulated to investigate the research questions.

Table 1.1: Research Question and Hypotheses

Main Research Sub Research Research Hypotheses Question Questions How can construction What are the types, material waste in the causes, and disposal NCI be minimised methods of material using the circular waste in the NCI? economy concept What are the attitudes, H01 – There is no statistically significant difference in the NBCFs’ awareness of material awareness, and waste based on a company’s size. perceptions about H02 – There is no statistically significant difference in the NBCFs’ awareness of material construction waste waste based on a company’s ownership status. minimisation by NBCFs? H03 – There is no statistically significant difference in the NBCFs’ awareness of material waste based on a company’s main construction activity.

H04 – There is no statistically significant difference in the NBCFs’ perception of material waste based on a company’s size.

H05 – There is no statistically significant difference in the NBCFs’ perceptions of material waste based on a company’s ownership status.

H06 – There is no statistically significant difference in the NBCFs’ perceptions of material waste based on a company’s main construction activity.

H07 – There is no statistically significant difference in the NBCFs’ attitude to material waste based on a company’s size.

H08 – There is no statistically significant difference in the NBCFs’ attitude to material waste based on a company’s ownership status.

H09 – There is no statistically significant difference in the NBCFs’ attitude to material waste based on a company’s main construction activity.

H10: Awareness of material waste is positively related to perception.

H11: Awareness of material waste is positively related to attitudes.

H12: Attitudes to material waste are positively related to perceptions.

What are the current H13 – There is no statistically significant difference in the NBCFs’ waste minimisation approaches adopted by approaches based on company ownership status. the NBCFs to minimise material waste at H14 – There is no statistically significant difference in the NBCFs’ waste minimisation design, procurement, approaches based on company size. and construction phases? H15 – There is no statistically significant difference in the NBCFs’ waste minimisation approaches based on the age of company.

H16 – There is no statistically significant difference in the NBCFs’ waste minimisation approaches based on a company’s main construction activity. To what extent has the 3Rs principle been adopted by the NBCFs? What policies or legislative measures are required for effective waste minimisation in the NCI? Can a circular- economy-based waste minimisation framework be adapted for minimising construction waste in the NCI?

1.5 Research Aim and Objectives The focus and novelty of this study is in the application of the CE to the construction industry. The research question and sub-questions described in Table 1.1 inform the aim and objectives of the study. Therefore, the principal aim of this research is to develop a circular-economy- based construction material waste minimisation framework for Nigeria with a view to achieving SC. The study also examines the behaviour of the NBCFs to waste minimisation and assesses how the CE framework can be used to minimise construction waste in the NCI. To achieve the aim, the specific objectives are to:

i. Identify the types, causes, and disposal of material waste in the NCI. ii. Investigate the awareness, attitudes, and perceptions of the Nigerian building construction firms (NBCFs) to material waste minimisation. iii. Investigate current approaches adopted by the NBCFs to minimise material waste at design, procurement, and construction phases. iv. Investigate the extent of adoption of the 3Rs principle by the NBCFs. v. Identify policies and/or legislative measures for waste minimisation and implementation methods that are appropriate for the NCI. vi. Investigate the readiness of the NCI to adopt a circular-economy-based waste minimisation framework.

1.6 Research Methodology Pragmatism was adopted as the philosophical paradigm underpinning the study, as it allows the use of multiple methods in studying a phenomenon (Richards & Morse, 2012). Convergent parallel mixed methods (Creswell & Plano Clark, 2017) were found to be appropriate, while the concurrent triangulation design was adopted for the research design (Creswell, Plano Clark, Gutmann, & Hanson, 2003). This approach allows quantitative and qualitative data to be collected and analysed simultaneously.

Primary data were collected using quantitative and qualitative methods through a questionnaire and interviews respectively. Both methods collected similar data on the research objectives subsequent to the limitations identified from literature. The convergent parallel mixed method allows for data to be analysed simultaneously and then merged for discussion. Quantitative data analysis was conducted through descriptive statistics, while detailed analyses include tests such as Friedman, Kruskall-Wallis, Kendall Coefficient of Concordance, Chi-Square, Relative Importance Index analysis, and Factor analysis. For all analyses, the Statistical Package for the

Social Sciences (SPSS) version 24 software was utilised. Thematic analysis of the qualitative data was undertaken using NVivo 11 Qualitative Data Analysis (QDA) software. Figure 1.1 provides an overview of the research methodology, which is described in details in chapter four while Table 1.2 summarises the inter-relationships between research sub-questions, objectives and methods.

Figure 1.1: Research methodology flowchart

Table 1.2: Relationship between research sub-question, objectives and methods

Research sub-questions Research objectives Research methods What are the types, causes, To identify the types, and disposal methods of causes, and disposal of material waste in the NCI? material waste in the NCI. What are the attitudes, To investigate the awareness, and perceptions awareness, attitudes, and about construction waste perceptions of the Nigerian minimisation by NBCFs? building construction firms Quantitative (Survey) and (NBCFs) to material waste Qualitative (Interviews and minimisation. direct observation) What are the current To investigate current approaches adopted by the approaches adopted by the NBCFs to minimise material NBCFs to minimise material waste at design, waste at design, procurement, and procurement, and construction phases? construction phases. To what extent has the 3Rs To investigate the extent of principle been adopted by adoption of the 3Rs the NBCFs? principle by the NBCFs. What policies or legislative To identify policies and/or measures are required for legislative measures for effective waste minimisation waste minimisation and in the NCI? implementation methods that are appropriate for the Quantitative (Survey) and NCI. Qualitative (Interviews) Can a circular-economy- To investigate the readiness based waste minimisation of the NCI to adopt a framework be adapted for circular-economy-based minimising construction waste minimisation waste in the NCI? framework.

1.7 Research Scope The focus of this study is the adoption of the CE concept as a waste minimisation method in the construction industry. The investigation focuses on the NCI, particularly the building construction sector. This sector was chosen because it has been shown to generate considerable amounts of waste and have low sustainable practices among industry professionals (Dania et al., 2007).

The investigation is limited to Lagos state owing to the prevalence (60%) of construction activities and clients (Ajanlekoko, 2001). Approximately 70% of registered construction firms have a head office or branch in Lagos (NIOB, 2005). Construction professionals were

surveyed. The survey focused on design, procurement, construction and implementation strategies for waste minimisation.

Construction waste exists in different forms: time, labour, materials, financial, and equipment (Garas, Anis, & Gammal, 2001; Pheng & Tan, 1997; Ekanayake & Ofori, 2000; Oladiran, 2009). This study investigates only material waste, which has a high capacity to contribute waste to landfill (Oyedele et al., 2013).

1.8 Contribution to Knowledge The concept of construction waste management, CE, and SC have been established by several studies. Expanding on existing information, this study seeks to provide insight into waste minimisation measures by integrating the CE concept into the construction industry. The findings from this investigation will help formulate models to reduce material depletion, resource extraction, and pollution. Therefore, this work provides: i. A frame for applying the CE concept for minimising waste in the construction industry. ii. A detailed insight into construction waste in Nigeria and the behaviour of NBCFs towards construction waste. iii. A model for minimising waste and promoting sustainable construction in the NCI. iv. A holistic CE framework for minimising waste across construction phases (design, procurement, and actual construction).

Furthermore, the study contributes to the NCI by: i. Creating awareness and understanding of the causes of material waste at different stages of construction. ii. Improving professionals’ knowledge and understanding of circularity in design, procurement, and construction. iii. Discussing appropriate approaches to material waste minimisation at the design, procurement, and construction phases. iv. Creating awareness for the formation of construction waste minimisation policies and regulations that are explicit to the industry.

The increasing volume of waste generated across the world and pollution from landfills emphasise the need to minimise construction waste. This thesis proposes a CE concept for waste minimisation. First, a holistic CE framework for minimising waste should lead to efficient planning and optimal use of building materials, thereby reducing waste at all

construction phases. Second, detailed insight into construction waste and the behaviour of NBCFs toward waste minimisation may help to tailor interventions to improve decision making and divert materials from landfills. Third, a model suitable for minimising waste and promoting SC in the NCI may serve as a prototype for other countries considering waste minimisation. Lastly, a holistic framework for minimising waste at all construction phases should provide a guide for efficient planning and optimal use of building materials.

1.9 Limitations of the Study The intent of this investigation was to examine construction material waste minimisation in the NCI with the purpose of diverting waste from landfill. However, there were some contextual, scope and methodological limitations that need to be acknowledged. First, only architects, project managers, engineers, foremen, quantity surveyors, main contractors, sub-contractors, and builders provided survey responses. Therefore, the results should not be generalised to other stakeholders. Second, data were collected from Nigeria, limiting generalisation of the findings to other countries. Third, participants were only recruited in Lagos. It can be argued that Lagos serves as a model for other states in Nigeria because all sizes of construction firms are represented there. Likewise, all types of construction activities, stakeholders, and institutions are available. Fourth, the questionnaire examined thoughts of respondents from different building construction firms. These thoughts were limited because respondents had restricted choice of answers. Interviews were conducted simultaneously with construction professionals on project sites to get a wide picture of the phenomenon. This was to overcome the limitations of each method and, at the same time, validate the data obtained. In addition, the interviews provided rich data from a relatively large sample in one location. A larger sample from multiple locations could enhance generalisability. It was hard to interpret conflicting results in the mixed methods approach. However, results for each method were discussed in the light of the phenomenon and different aspects were captured. Fifth, there is a lack of industry data on the actual volume of waste generated and details of all ongoing construction projects in Lagos and Nigeria as a whole. For example, the website of the Lagos State Government Building Control Agency (LASBCA), the government agency responsible for approving construction projects, was checked for lists of projects, but none was found (see Appendix A). This limitation was overcome by informal discussions with construction professionals who provided a list of projects they were handling. Lastly, evaluating the proposed CE minimisation framework and the competencies of the NBCFs in implementing waste minimisation approaches was beyond the scope of this study. However, their readiness

to adopt new waste minimisation methods was investigated. The proposed framework provides a guide for minimising material waste and does not guarantee success.

1.10 Thesis Structure The thesis consists of eight chapters. The contents and relationships of the chapters are illustrated in Figure 1.2 and described below: Chapter one provides the background and rationale for the study. It briefly discusses the research problems and gaps in the literature. It highlights the research aim, specific objectives to achieve the aim, and research questions. In addition, it provides a synopsis of the extensive research methodology, scope of the investigation, significance and limitations. The chapter concludes by reiterating the significance of the study and structure of the thesis.

Chapter two examines the literature on construction waste. It reviews the concept of waste, and causes, types, composition and sources of waste. In addition, it highlights waste management strategies and techniques practiced across the globe, as well as drivers for material waste minimisation. Sustainable development, sustainable construction, and sustainable waste management concepts are critically reviewed, and the existing institutional, legislative, and conceptual frameworks underpinning construction waste management are discussed. The chapter provides background information about the construction industry and profiles the NCI, including existing waste management policies and legislation.

Chapter three reviews literature about the CE and its origin, principles, and characteristics. Theoretical concepts and frameworks underpinning the CE, such as industrial ecology, cradle to cradle, biomimicry, performance economy, regenerative design, permaculture, and the blue economy system are reviewed. The relationships between the CE and sustainable development are highlighted, as well as their opportunities. In addition, economic and social impacts of the CE are discussed. The drivers, challenges, and benefits of the CE form part of the review. In addition, the relationship between the CE and SD are highlighted, while the opportunities and practical approaches of the CE in the construction industry are discussed. The chapter concludes with a theoretical perspective of the CE based on the diffusion of innovation theory.

Figure 1.2: Thesis layout

Chapter four describes the research process and methodology adopted. The chapter starts by describing the research paradigm, where reasons for the choice of pragmatism are highlighted. Thereafter, the rationale for adopting a mixed method approach and concurrent triangulation design are presented. The chapter in addition justifies a questionnaire as the method for quantitative data collection and presents details of the sampling techniques and pre-testing of the instrument. Quantitative data analysis methods, including descriptive statistics, relative important index analysis, and factor analysis are highlighted. Similarly, the choice of interviews as the qualitative method for data collection and details of target participants, interview structure, pilot survey, and protocol for the interview are presented. The procedure for conducting thematic analysis (the qualitative data analysis method used) is described. Validity, reliability and generalisability of the study’s findings form the crux of the chapter.

Chapter five presents the results of the data collection, drawn from the descriptive and inferential statistics analyses and thematic analysis of the quantitative and qualitative data respectively. The chapter is presented in two sections. The first reveals the findings from the questionnaire survey. It describes the sample characteristics, response rate, and respondents and organisations’ demography. In addition, results from the analysis of primary data organised according to the research questions are presented, as well as their implications. The second section details results of the interviews and provides demographic information about the interviewees and their projects. It captures the opinions of interviewees, presenting them as themes emerging from the study. As in the first section, the findings are organised to align with each research question. The major findings of the research are presented in chapter five.

Chapter six integrates the findings of the quantitative and qualitative data presented in chapter five to form a basis for discussion – the main purpose of the concurrent triangulation design adopted. The chapter provides insight into the differences and similarities in quantitative and qualitative results. It offers a comprehensive discussion of key findings according to the research objectives. For each objective, it summarises the results, discusses its meaning, relevance to policies and practices, contributions to existing literature, and comparisons to previous studies. A part of this chapter is exclusively devoted to the circular-economy-based construction waste minimisation framework, which is the overarching aim of this study. The chapter then presents the framework in five sections based on key issues identified in the study, and, in conclusion, it provides answers to the research questions.

Chapter seven, the final chapter, summarises the entire study by providing general conclusions as well as conclusions for each objective of the study. It highlights contributions to knowledge in terms of implications for practice and theoretical implications. The chapter makes provisional statements in the form of recommendations for policy, training and education, changes in organisational culture and attitude, best practices, as well as research and development. It also identifies limitations of the research and areas for further or future investigation.

1.11 Summary In summary, chapter one has provided an overview of literature on construction waste minimisation, identified existing deficiencies and the proposed aims to address these gaps. It has introduced the concept of the CE for minimising construction material waste at the design, procurement, and construction phases. The chapter highlights the research question: “How can construction material waste in the NCI be minimised using the circular economy concept?” and provides a concise summary of the methodology used to answer the question. The scope, contribution, significance and limitations of the study were also summarised.

The following chapter (chapter two) reviews literature on construction waste and its management. The review focuses on the construction industry’s sustainability concepts with specific focus on waste management. Its application and implementation in the NCI is also discussed.

CHAPTER TWO CONSTRUCTION WASTE MINIMISATION 2.0 Chapter Overview Chapter one discussed the research problem and identified gaps in the literature to justify the study. The aim, objectives, scope and limitations were also identified. This chapter explores the key concepts of sustainable development and construction. A review of construction waste, highlighting its generation, causes, types, composition, and quantification are conducted. Subsequently, insights into construction waste minimisation are provided, highlighting the drivers, benefits, and obstacles. Building Information Modelling (BIM) is discussed as one of the study’s conceptual frameworks. Thereafter, the theory of waste behaviour (the theoretical foundation of this study) is reviewed, leading to a discussion of perceptions of sustainability in the construction industry. The chapter then provides a synopsis of the NCI, its contributions to GDP, its formal and informal sectors, and the types of contracting firms operating in Nigeria. The government’s roles, including provision of educational services, is highlighted. Insight into the demand and supply of infrastructure is provided, leading to a discussion about the opportunities and challenges facing the industry. Subsequently, a review of the regulatory framework, construction policies, and regulations is provided. This is followed by a review of construction policies relating to the environment, national building codes, local content legislation, and national environmental regulations. In conclusion, Nigeria’s efforts to ensure sustainability through contributions to sustainable development goals, vision 20:2020, and the national environmental summit are discussed.

2.1 Construction and Sustainable Development 2.1.1 Sustainable Development The World Commission on Environment and Development (WCED, 1987) described sustainable development (SD) as “development that meets the need of the present without compromising the ability of future generations to meet their own need” (p. 66). Several other definitions have emerged due to Oskamp’s (2002) criticism of the WCED’s definition as too elementary. According to Emmanuel et al. (2014), SD is achieved by integrating social, economic, and environmental factors. According to Ortiz, Castells, and Sonnemann (2009), it is about “enhancing quality of life and thus allowing people to live in a healthy environment and improved social, economic and environmental conditions for present and future generations” (p. 29). It is obvious from these definitions that SD emphasises social, environmental, and economic factors, which suggests the need to ensure balance and interplay

between them. As a result, world leaders met in 2015 to discuss and sign Agenda 30, which involves 17 SD goals. To achieve these goals, support from industries such as the construction industry would be required, while some of the sustainable development goals may be dependent directly or indirectly on the construction industry.

2.1.2 Concept of Sustainability Sustainability is “the condition or state which would allow the continued existence of Homo sapiens, and provide a safe, healthy and productive life in harmony with nature and local cultural and spiritual values” (Du Plessis, 2002, p. 6). It is a process that protects the environment over time without exceeding its bearing capacity (Neuman and Churchill, 2011). These definitions indicate that sustainability is multidimensional in nature and has no common definition. Arguably, the term “sustainability” has achieved global recognition and most industries have found a way to adopt it into their practices. For example, its application in the construction industry is known as sustainable construction, and other applications include sustainable agriculture, sustainable marketing, and sustainable consumption. The concept of sustainability has also been adopted by organisations, governments, businesses, institutions, and individuals (Yao, 2009). Sustainability is important because it can improve air quality, save cost, and increase safety. Despite its wide acceptance and advantages, it is not well understood and communicated (Newport, Chesnes & Lindner, 2003). Its definition is based on personal opinions (Kemp & Martens, 2007), and may be problematic (Leiserowitz, Kates, & Parris, 2006). However, it is applicable to all spheres of life (Emmanuel et al., 2014), and more importantly plays a role in reducing the human ecological footprint.

2.1.3 Construction Construction as a process involves the craftsmanship of distinctive parts to form a structure. The construction process refers to actions taken in producing a project. Hobday (2000) described a project as including activities limited by time with a distinct set of resources and goals. Similarly, Turner (2006) referred to it as an activity aimed at achieving a short term objective by accumulating various resources. Keywords in these definitions are timeframe, resources, and goal or objective. Therefore, construction is a project-based activity (Fellows, Langford, Newcombe, & Urry, 2009) and has been described as “the broad process/mechanism for the realisation of human settlements and the creation of infrastructure that supports development” (Du Plessis, 2002, p. 4). According to Irurah (2001), four levels are involved in construction. The first is site activity, which results in the realisation of buildings. The second is a comprehensive project cycle that encompasses a feasibility study, design, actual

construction, operation, decommissioning, demolition, and disposal (Du Plessis, 2007). The third level is about the business of construction, while the last level involves human settlement creation. Construction processes and operations are categorised and executed in phases that could be in sequence or occur simultaneously.

2.1.3.1 Construction Process and Operation The construction industry is dynamic. Its processes involve the design and production of structures (Widén, 2002). The construction process shown in Figure 2.1 provides an overview of the activities within the industry. These activities may be categorised as input and output, with the former representing resources that are invested into a project (such as client brief, funds, and materials). Outputs refer to end products of construction activities, including infrastructure, waste, job opportunities, and contribution to GDP. The focus of this study is on waste output.

Figure 2.1: Overview of the construction industry

2.1.3.2 Construction Phases There are many phases in a construction project, depending on the project’s size, scope, and timeframe. The Royal Institute of British Architects (2013) has identified the phases in building construction, and they include briefing, sketch plans, working drawings, site operations, and feedback. These phases have been adopted in the NCI for most organised (formal) construction

projects. Ahadzie, Proverbs, and Olomolaiye (2006) have reiterated that these phases are essential any construction development success of. Ankrah (2007) has supported Ahadzie et al.’s view, and highlighted the significance of the actual construction phase in determining a project’s success. Lim and Mohamed (1999) also confirmed the focus on the construction phase due to its complex nature. The pre-construction and post-construction phases (especially design and deconstruction/demolition) are also important when examining the success of construction projects. For the purpose of this study, construction phases have been categorised into design, procurement, and construction phases. Although there are different stages in design, this study focuses on the design development and technical design stages as identified by the Royal Institute of British Architects (2013).

2.1.4 Sustainable Construction (SC) The decision to embark on a construction project significantly impacts the environment and resources. Therefore, the activities involved in a project require integrated management from inception to completion to achieve SD (Guerin, 2017; Hwang & Ng, 2013). Aside from environmental benefits, a project that considers the environment can preserve construction costs and reduce delays (Guerin, 2017) while contributing to sustainable economic development. Ding (2008) states that an effective way to achieve SD is to consider and solve environmental problems at the initial stage of a project (i.e. before implementation). Therefore, SC is a stategy that meets the needs of the construction industry in creating a green built environment, and its purpose is to achieve SD (Abidin, 2010; Dickie & Howard, 2000). The Conseil International du Batiment in 1994 defined SC as “…creating and operating a healthy built environment based on resource efficient and ecological principles” (Kibert, 2012, p. 79). In addition, “Agenda 21” for SC in developing countries described SC as “a holistic process aiming to restore and maintain harmony between the natural and built environments, and create settlements that affirm human dignity and encourage economic equity” (Du Plessis, 2002, p. 8). These definitions indicate that SC addresses the ecological, economic and social issues of buildings (Kibert, 2012) and is commonly adopted in describing pre-construction, actual construction, and post construction processes.

The Lafarge Holcim Foundation (2015) identified several issues relating to SC, including “the design and management of buildings; materials performance; construction technology and processes; energy and resource efficiency in building, socially-viable environments; stakeholder participation; and flexibility in building use”. These issues align the industry with the SD agenda (Murray & Cotgrave, 2007). They also indicate that implementing SC may be

21 challenging for stakeholders involved with construction. However, previous studies (Shen, Song, Hao & Tam, 2008; Matar, Georgy, & Ibrahim, 2008) have recommended that stakeholders exhibit SC practices by integrating SD principles throughout a project’s lifecycle, which suggests a working relationship between SD, SC, and sustainability. Figure 2.2 illustrates how sustainability and SC service SD, with SD being the overarching aim. The goal of sustainability in construction is to achieve SD, while SC is the industry’s means of achieving SD. It is obvious that sustainability and SC are mutually inclusive. However, SC achieves SD through environmental, social, and financial aspects of sustainability.

Figure 2.2: Relationship between SD, SC and Sustainability 2.1.4.1 Sustainable Construction Principles To achieve SD, SC focuses on resource efficiency, environmental protection, and waste minimisation. These themes form the basis of SC principles, which are: “reduce resource consumption; reuse resources; use recyclable resources; protect nature; eliminate toxics; apply life-cycle costing; and focus on quality” (Kibert, 2012, p. 8). These principles are vital to the success of construction projects and are applicable at all phases of construction. They inform a project participant’s decisions and should be carefully considered, especially when integrating construction issues (such as environmental, social, economic, and political issues) in realising SD (Al-Yami & Price, 2006). Additionally, Kibert (2012) has emphasised the interrelationship between construction phases, a project’s essential resources, and SC principles in achieving sustainability and solving built environment issues. This suggests the need for integration between these areas. A project’s essential resources are land, materials, water, energy, and ecosystems, while construction phases are design, procurement, and actual construction as identified for this study. The relationship between SC principles and construction phases is described in Table 2.1 and Figure 2.3. This relationship suggests that SC principles are important at all phases of construction. Understanding these principles is important for all stakeholders and, as suggested by Fadeyi, Jallow, Anumba, and Dulaimi

(2013), has the capacity to inform a client’s decision in appointing professionals with track records in sustainable practices. In addition, it could aid the application of these principles during their corresponding phases. Abidin (2010) observed that professionals with detailed knowledge of SC principles are likely to make appropriate decisions leading to the overall success of a project. The following elements are required to achieve sustainability – stakeholders’ decisions, construction phases, SC principles, government mechanisms, and clients’ requirements.

Table 2.1: Relationship between SC and Construction phases

SC Principles Construction Phase Author(s) and year Reduce • Design Ghisellini et al. (2016); Su et al. (2013); Damen (2012); • Procurement Liu (2012); Ness (2008); European Union (2008); Yong • Construction (2007); Zhijun and Nailing (2007); Shi et al. (2006) Reuse • Construction Castellani et al. (2015); Su et al. (2013); Stahel (2013); Liu (2012); James (2011); European Union (2008); Shi et al. (2006) Recycle • Construction Ghisellini et al. (2016); Birat (2015); Moreno et al. (2015); Van den Berg and Bakker (2015); Murray et al. (2017); Su et al. (2013); Lazarevic et al. (2012); European Union (2008); Dajian (2008); Duran et al. (2006); Shi et al. (2006) Protect nature • Design Kibert (1994). • Procurement • Construction Eliminate • Design Pacheco-Torgal and Jalali (2011); Doroudiani and toxics • Procurement Omidian (2010); Liang and Ho (2007); Kibert (1994) • Construction Life cycle • Design Ashworth and Perera (2015); Ashworth and Hogg (2014); costing • Procurement Fuller (2010); Flanagan and Jewell (2008); Langdon • Construction (2007); Ellingham and Fawcett (2007); International Standard Organisation (2006); Clift (2004); Mat (2002); Sterner (2000) Quality • Design Ashokkumar (2014); Arditi and Gunaydin (1997); Kibert • Procurement (1994) • Construction

Reduce

Reuse Design Phase

Recycle

Procurement Protect nature Phase

Eliminate toxics

Construction Life cycle costing Phase

Quality

Figure 2.3: Framework for the relationship between SC and Construction phases

2.2 Construction Waste Construction waste can be defined as excess from a production process that can be used in the production of other components or materials (Omole & Isiorho, 2011). Therefore, it includes resources that are no longer needed (Oyedele et al., 2013) and are awaiting prompt disposal (European Commission, 2008). According to Mata, Pitroda, and Vyas (2015), construction waste has increased globally due to increased construction activities resulting from urbanisation. In 2014, about 333 million tonnes of construction and demolition (C&D) waste was generated in the European Union (EU) (Eurostat, 2018). In the same year, approximately 534 million tonnes of C&D waste was generated in the US (US EPA, 2016), while in Australia, 19.5 million tonnes was generated (Pickin & Randell, 2017). In addition, Arponen, Granskog, and Pantsar (2015) observed that 16.2 million tonnes of waste was generated in Finland, while in Hong Kong, it increased from 4.26 million tonnes in 1991 to 6.3 million tonnes in 2011 (Environmental Protection Department, 2018). There is growing impetus to find lasting solutions to the issue of waste. Arguably, the first step is to acknowledge that the problem exists and to identify its source and causes, and thereafter, to proffer solutions. These are explored below.

2.2.1 Generation and Causes of Construction Waste The generation and causes of waste vary, depending on the construction activity, site, and practice (Jones & Greenwood, 2003). Several studies (Nagapan et al., 2012; Al-Hajj & Hamani, 2011; Gamage, Osmani, & Glass, 2009; Kofoworola & Gheewala, 2009; Esin and Cosgun, 2007, Formoso, Soibelman, De Cesare, & Isatto, 2002) have identified causes, which include: inadequate storage facilities, off-cuts of materials, improper handling of materials, poor site management practices, material spillage and left over, poor supply chain management, contractors’ inexperience, mistakes, rework, and inadequate scheduling. These causative factors have been categorised into seven groups, and significant factors (in italics) under each group were identified by Nagapan et al. (2012) and Mata, Mendes, Caetano, and Martins (2014), as shown in Table 2.2.

Table 2.2: Significant factors contributing to construction waste

Category Significant factor References Research methods Design • Frequent design Gamage et al., 2009; Polat & Case studies; changes Ballard, 2004; Ekanayake & Ofori, Direct observation; • Design errors 2004; Garas et al., 2001; Coventry et Literature review; • Lack of details al., 2001; Faniran & Caban, 1998 Questionnaire survey • Poor project quality Handling • Poor material Lu, et al., 2011; Lu, Shen, & Yam, storage 2008; Kofoworola & Gheewala, 2009 External • Effect of weather Senaratne & Wijesiri, 2008; Faniran Factor & Caban, 1998; Bossink & Brouwers, 1996 Management • Poor planning Wahab & Lawal, 2011; Kofoworola & Gheewala, 2009; Tam, Shen, & Tam, 2007; Poon, Yu, & Jaillon, 2004; Formoso et al., 2002; Bossink & Brouwers, 1996 Procurement • Ordering errors Lu et al., 2011; Gamage et al., 2009; Wang, Kang, & Tam, 2008; Esin & Cosgun, 2007; Greenwood, Jones, Snow, & Kersey, 2003; Faniran & Caban, 1998 Workers • Workers’ mistakes Nagapan et al., 2012 Site • Materials left on Wahab & Lawal, 2011; Kofoworola condition site & Gheewala, 2009; Tam, Shen, & Tam, 2007; Poon et al., 2004; Formoso et al., 2002; Bossink & Brouwers, 1996 Source: Adapted from Nagapan et al, 2012; Mata et al., 2014 & Ajayi, 2017

From Table 2.2, it is evident that waste is generated throughout the construction process. Although minimising waste at the design phase may be effective in reducing overall waste (Osmani, et al., 2008), some construction activities also generate waste. Therefore, there is a need for a holistic waste minimisation framework encompassing the three major construction phases (design, procurement, and construction) as suggested by Hao et al. (2008) and Esin and Cosgun (2007).

2.2.2 Types of Construction Waste Construction waste can be categorised into two types, which are tangible and intangible waste (Nagapan et al., 2011).

i. Tangible Waste

Tangible waste can be described as a blend of used and unused materials resulting from construction, demolition, and other construction-related activities (Kofoworola & Gheewala, 2009; Tam & Tam, 2008; Poon, 2007). These include waste generated from materials such as concrete, bricks, tiles, reinforcement bars, wood, cardboard, paper, as well as topsoil (Katz & Baum, 2011; Hao et al., 2008). Tangible waste can be further categorised into material waste, labour waste, and machine waste (Ekanayake & Ofori, 2000). Of these three, material waste is commonly generated (Osmani et al., 2008; Garba, Olaleye, & Jibrin, 2016; Nwokoro & Onukwube, 2011; Zuo and Zhao, 2014; Oladiran, 2009a) and hence is the focus of this study. ii. Intangible Waste

Nagapan et al. (2012) described intangible waste as non-value-adding construction activities resulting in project costs and time overruns. Womack and Jones (1996) referred to such waste as intangible and indirect waste absorbing resources while creating no value. Examples include overordering of materials, inappropriate storage of materials, construction process waiting time, and poor project and human management (Formoso, Isatto, & Hirota, 1999; Koskela, 1992). Skoyles and Skoyles (1987) cited in Bekr (2014) observed that this indirect waste generally results in monetary loss.

Globally, both tangible and intangible wastes are evident in the construction industry (Ekanayake & Ofori, 2000, Bekr, 2014) but differ based on the construction phase (Greenwood, Jones, Snow, & Kersey, 2003). Consequently, the construction sector is viewed as generating unacceptable levels of material waste (Ekanayake & Ofori, 2000). This calls for investigations

to identify types, causes, and disposal methods, which could help in developing appropriate strategies and implementation methods to minimise construction waste.

2.2.2.1 Waste Composition Material waste composition on project sites varies depending on the construction activities, methods, and country in which they occur (Begum, Siwar, Pereira, & Jaafar, 2006; US EPA, 1998). Lau et al. (2008) studied waste composition from three residential buildings in Malaysia and found that wood (56.2%), concrete (23.6%), brick (14%), metal (2.5%) and others (3.8%), such as ceramic, PVC pipe, and plaster, were materials wasted. A similar study in Thailand identified wood, concrete, and ferrous metals as construction waste materials (Kofoworola & Gheewala, 2009). In Spain, bricks, tiles, and ceramics made up 54% of the total construction waste, concrete 12%, stone 5%, asphalt 5%, aggregates (sand and gravel), 4%, wood 4%, metal 2.5%, glass, 1.5%, plastic 1.5%, gypsum 0.2%, paper 0.2%, and others not categorised were 3.1% (Spain, 2001). Cochran and Townsend (2010) have emphasised the need to understand the composition and size of the waste stream to design and implement appropriate management plans. The availability of data on the components of waste is essential to enable improvements to existing waste management plans and to develop a waste minimisation framework.

2.2.2.2 Waste Quantification and Prediction Lau et al. (2008) have demonstrated how waste can be quantified to estimate waste volume. In their study, waste was categorised into four types – stockpiled, scattered, gathered, and stacked. The volume can be calculated according to recognised quantity surveying principles (see Seeley (1997)).

2.3 Construction Waste Minimisation Waste minimisation encompasses all processes involved in waste volume reduction (US EPA, 2000). It may involve techniques, processes or activities aimed at avoiding, eliminating or reducing waste at its source, thereby allowing these wastes to be reused or recycled (Poon & Jaillon, 2002). According to Osmani (2011), construction waste minimisation includes the identification of causes, reduction of sources, and application of strategies and techniques to facilitate reduction. Several other studies (Yuan, 2013; Osmani, 2011; WRAP, 2007b, 2009a; Osmani et al., 2008) have highlighted waste minimisation strategies at the design, procurement, and construction phases. These emphasise the need to minimise waste before it is generated rather than manage it after generation. Legislative approaches to minimise waste have also

been identified (Brown & Johnstone, 2014; Oyedele et al. 2013; Yuan 2013; Tam, Shen, Fung, & Wang, 2007).

At the design phase, WRAP (2009a) identified five strategies, including design for material optimisation (DfMO), design for off-site construction (DfOC), design for waste-efficient procurement (DfWEP), design for reuse and recovery (DfRR), and design for deconstruction and flexibility (DfDF). Similarly, Osmani (2011) found that the common design approaches practiced by architectural and construction firms in the UK included avoidance of late variation in design, use of prefabricated units, use of standard dimension and units, specifying reclaimed/recycled materials, designing for deconstruction, and feasibility studies of waste estimation. In addition, dimensional coordination of design elements and modular design were acknowledged by Formoso et al. (2002). Another important strategy for waste minimisation at the design phase is the use of waste prediction tools. Poon, Yu, and Ng (2001) developed a waste index that estimates the volume or weight in square metre per floor area. Similarly, Solís- Guzmán et al. (2009) developed a classification model that uses a waste index from a database to predict waste quantity. The UK Building Research Establishment (BRE) has produced an online waste management tool (SMARTWaste) that estimates waste based on data previously gathered from construction projects. Similar to Poon, Yu, and Ng’s (2001) waste index, Jalali (2007) developed a “Component Index” that uses global data to forecast waste per square metre of floor area. In addition, Jalali (2007) developed a “global index” tool that predicts volumes of waste using building components such as types and quantity of doors, windows, columns, and beams.

The UK WRAP (2008) developed a tool known as NetWaste, which estimates the cost and quantity of waste from basic project information (e.g. materials) to determine an appropriate waste minimisation strategy. There are additional tools such as Design-Out Waste Tools for Builders (DOWT-B) and Design-Out Waste Tools for Civil Engineers (DOWT-CE), developed by WRAP to assist construction professionals in identifying and minimising potential waste. In Singapore, Ekanayake and Ofori (2004) developed the Building Waste Assessment Score (BWAS) to assess possible waste from designs and to stimulate prompt minimisation measures. Several other waste prediction tools have been developed around the world. While these forecasting tools stimulate stakeholders to take actions that they might not have otherwise contemplated, they have rarely been adopted on construction sites since they rely on existing data. Furthermore, the accuracy of the data and estimates collected is uncertain, and it is uncertain whether they can redirect waste on their own. There are various strategies or

measures that can be employed to minimise waste at the design phase. For a comprehensive list of design approaches, refer to Appendix B.

At the procurement phase, Greenwood et al. (2003) identified some factors that could help prevent waste, including careful storage of materials, on-time delivery of materials, stocktaking of materials, avoiding over-ordering of materials, and procuring materials with minimal packaging. In support of Greenwood and colleagues, Dainty and Brooke (2004) emphasised the importance of just-in-time (JIT) delivery and less packaging of materials to reduce waste during procurement. Although JIT is intended to ensure prompt delivery of materials as and when required to avoid damage resulting from extended storage (Dainty and Brooke, 2004), it does not guarantee this. Some materials are packaged with a combination of polystyrene foam and cardboard boxes, which generate waste. Therefore, Dainty and Brooke (2004) suggests the need for collaboration among all stakeholders involved with the design, production, and supply of materials in minimising material packaging waste. A detailed list of material procurement approaches is provided in Appendix C.

Waste minimisation strategies employed at the construction phase include material reuse, sorting and recycling, and off-site construction. According to den Hollander, Baker, and Hultink (2017), reuse is “any operation by which products or components that are not waste are used again for the same purpose for which they were conceived” (p. 518). Therefore, material reuse offers opportunities to reduce and divert waste from landfill. Construction waste can be reused in so many ways, either on the same project or another, directly or indirectly (i.e. as a component of another material) and may or may not require additional processing. Not all materials can be reused, and some have a limited number of uses (Ajayi, 2017), suggesting that such materials are landfilled. As a result, the strategy of reusing materials has been criticised for not preventing all waste from being sent to landfill. However, it has and still is being used in preference to recycling in the construction industry (Moreno et al., 2015). Sorting and recycling as a strategy for minimising and diverting material waste from landfill has been considered in the industry. Sorting, a prerequisite for recycling, involves collecting recyclable materials before and after they are mixed. Recycling involves collecting and converting waste materials into new products (US EPA, 2016) through mechanical processes. Recycling may be adopted on construction projects to manage waste rather than minimise waste. Its benefits include material recovery, reducing waste sent to landfill, preventing pollution, and reducing material extraction (Davidson, 2011; US EPA, 2016). Despite these significant advantages, recycling has been criticised for consuming energy and emitting carbon dioxide (Saraiva et al.,

2012; Chong and Hermreck, 2011). In addition, recycling is not thriving due to lack of mature markets and little or no marketing for recycled products (Yuan, 2013; Jain, 2012; Yuan, Shen, & Wang, 2011). Ajayi (2017), and Oyedele et al. (2013) have observed that recycling is not a holistic waste management strategy, since materials such as excavated soil, window panes and insulation materials cannot be recycled. Therefore, there is a need for sustainable waste minimisation measures.

Another important waste minimisation strategy that has been used during the construction phase is off-site construction. Prefabrication and precasting are examples of off-site construction techniques that have demonstrated efficiency in minimising waste (Lu & Yuan, 2013; Jaillon et al., 2009). These techniques involve the manufacture of building components such as kitchen pods, bathroom pods, floor bases, and wall panels in factories. These are assembled or installed on site. Off-site construction is fast becoming a method of choice due to its potential for fast timeframes, consistent quality, low labour cost, and less waste. A study by Jaillion et al. (2009) revealed that prefabrication can save up to 52% material waste. Likewise, Tam, Tam, Zeng, and Ng (2007) observed that about 84.7% waste could be minimised. As a result, off-site construction is gaining traction in the industry but is yet to be widely adopted. Previous studies (Jaillon & Poon, 2009; Goodier & Gibb, 2007) have found that the main barrier is the notion that it is expensive. A comprehensive list of construction approaches to waste minimisation can be found in Appendix D.

Legislative measures have been employed by governments to minimise waste at different phases of construction. Some of these measures include Site Waste Management Planning (SWMP), Pay-as-You-Throw (PAYT), Construction Waste Disposal Charging Schemes (CWDCS), and Extended Producer Responsibility (EPR), which are explained below:

• SWMP: SWMP was enacted into law in the UK in 2008 but revoked in 2013. According to SWMP regulation (2008), construction projects worth £300,000 and above were required to provide holistic waste management plans (from inception to completion). According to Greenwood et al. (2003), the plan provided an estimate and identified types of potential waste sources. It also included details of minimisation and management measures, including reuse, recycling, and disposal procedures. SWMP was expected to identify the client, principal contractor, person responsible for waste management, person who drafted it, site location, estimated project cost among others (HM Government, 2008). Although now repealed, some professionals and organisations still provide the plan to comply with the Building Research

Establishment Environmental Assessment Method’s (BREEAM) certification. Tam (2008a) has revealed that the SWMP adopted in the Hong Kong construction industry in 2003 has been criticised for reducing productivity. Whereas, in Australia, especially in New South Wales, it is a prerequisite for planning approvals for large construction projects (Hardie, Khan, O’Donell, & Miller, 2007). The principal aim of SWMP is waste reduction, which is usually managed by a site waste manager or other stakeholder as proposed by the plan (Tam, 2008a). Regardless of whether SWMP is a legal requirement or not, it is the responsibility of all stakeholders to minimise waste. Ajayi (2017) noted that most site waste management plans in the UK are prepared only to satisfy legal requirements and garner BREEAM points rather than reduce actual waste. However, it has been recommended by several authors (Ajayi, 2017; Tam, 2008a) as a potential legislative measure to minimise waste, cost, and pollution.

• PAYT: This is a government measure to divert waste from landfill. It is a program where waste is charged per unit volume for disposal. The purpose of PAYT is to encourage reuse, recycling and waste reduction. Previous studies (Brown & Johnstone, 2014; Dahlén & Lagerkvist, 2010) have shown that it is an effective method of minimising waste that is landfilled. With PAYT, the less waste generated, the greater the savings on disposal costs, and vice versa. Three key features of PAYT are environmental sustainability (reduce, reuse, and recycle), economic sustainability (generates revenue for management), and equity (pay per waste generated). These are SD principles, which suggests that PAYT is a sustainable scheme. It also has the potential to affect attitudes positively. For instance, Al-Hajj and Hamani (2011) observed that an increase in price per unit volume of waste disposed has increased construction firms’ commitment to strategic waste management.

• CWDCS: This is a Hong Kong government initiative to reduce and divert construction and demolition waste from landfill. In 2005, CWDCS was introduced to motivate producers to reduce, reuse, and recycle waste. A fee of HK$125 per ton is charged to dispose of waste in landfill, while HK$100 per ton and HK$27 per ton are charged for disposed of waste in sorting facilities and public fill receptions respectively (Poon, Wu, Yong & Yip, 2013). Evidence (Yu, Poon, Wong, Yip, & Jaillion, 2012; Environmental Protection Department, 2007) suggests that the scheme was successful in reducing waste during the first three years of implementation. Hao, Hills, and Tam (2008) have revealed that CWDCS was responsible for about 65% waste reduction to landfills in Hong Kong. Poon et al. (2013) observed a slight improvement in waste reduction and low awareness of waste management due to the low cost of CWDCS. Similarly Ann et al. (2013) revealed that sub-contractors are yet to be motivated by CWDCS. However,

based on Hong Kong’s Environmental Protection Department’s assessment, this approach has potential to be successful.

• EPR: This is a legislative concept that requires producers to exhibit a significant level of either physical or financial responsibility for their products from inception (pre-consumer stage) to disposal (post-consumer stage) (OECD, 2001, 2005). Manufacturers assuming this role could benefit from incentives to minimise waste, designing products for the environment, and recycling and reusing materials (OECD, 2005). The goal of EPR is to reduce waste volume, waste disposal, hazardous contents in waste streams, extraction of virgin materials, pollution at production stage, and decrease environmental impacts of products (Walls, 2004). The term EPR was first coined in Sweden, and has become a significant environmental policy, especially in Europe (Walls, 2006). There are different policy instruments contributing to the success of EPR, one being the “take back” approach. Here, a mandatory requirement is placed on manufacturers by the government to receive back products at the end of their lives. This approach has been adopted in some countries. For instance, in Germany, it is recognised as “take-back” law, in Australia, it is known as a “return and earn” scheme and adopted for plastic and glass bottles, while in the US, a voluntary product take back system (product stewardship) is used for rechargeable batteries and carpets (Walls, 2006). EPR thus deals with producers’ commitment to reducing the environmental impacts of their products. It has been criticised for not highlighting specific environmental impacts and other stakeholders involved in the manufacture, supply, and usage of products. Hence, there is a need to extend the policy to other stakeholders, such as retailers, consumers, and hauliers to identify specific environmental issues related to their activities and to encourage them to be responsible.

Other legislative measures that promote waste minimisation are highlighted in Table 2.3.

Table 2.3: Legislative measures for waste minimisation

Category Measures References Taxes/Levies Increasing mixed waste fees Cha, Kim, & Han (2009) Reducing separated waste fees Cha et al. (2009) Tax breaks for waste treatment Jingkuang & Yousong equipment (2011) Increasing the landfill disposal fee Lu & Yuan (2010) Regulations Improving waste management Lu & Yuan (2010) regulations Government/Organisational Improving database management for Cha et al. (2009) commitment construction waste Developing market structure for Oyedele et al. (2013); Cha recycled materials et al. (2009)

Category Measures References Integrating construction waste Yuan (2013b) management into the assessment of contractors Source: Adapted from Ajayi (2017)

2.3.1 Drivers of Construction Waste Minimisation Waste generation is driven by expanding economies, increased goods production and growing populations (World Bank, 2018a). Efforts to minimise waste to protect the environment and reduce resource extraction have increased globally and across many industries. In the construction industry, waste minimisation efforts have been supported by several factors. Wilson (2007) identified six drivers, which are institutional and responsibility issues, environmental protection, public health, closing the loop, resource value of waste, and public awareness. These factors were categorised into four types – environmental, economic, human, and institutional, by Agamuthu, Khidzir and Hamid (2009). Likewise, Osmani (2011) identified four categories of drivers, which are legislative, financial, business, and environmental drivers. A list of factors under these categories is shown in Table 2.4. This categorisation suggests that the drivers are inter-connected and can help develop effective waste minimisation techniques at all construction phases.

Table 2.4: Drivers of sustainable waste management

Category Factors Environmental • Climate change • Resource efficiency Economic • Funds availability and socio-economics • Waste to profits Institutional • Scientific research and development • Corporate image and financial gain Human • Population growth and high waste generation • Health and safety • Education and awareness • Stable leadership Legislation • Law/Regulatory policies • Guidelines • Incentives Source: Adapted from Wilson (2007) and Agamuthu, Khidzir and Hamid (2009)

2.3.2 Benefits of Construction Waste Minimisation Waste management strategies, if fully implemented viz-à-viz waste management hierarchy (reduce, reuse, recycle, treatment, and disposal (Gertsakis & Lewis, 2003)), has the potential to generate numerous beneﬁts throughout the entire waste lifecycle. According to El-Haggar

(2007), appropriate implementation of waste management methods will provide economic beneﬁts. For instance, Oyenuga and Bhamidimarri (2015) observed that the application of reduce, reuse, and recycling principles can lead to considerable savings for the UK construction industry. Waste minimisation plays a vital role in conserving the planet’s environment. It can reduce negative environmental effects such as pollution and emissions if waste deposited in landfill sites is reduced (Hwang & Bao Yeo, 2011).

Waste minimisation can provide financial benefits over a short- or long-term period to both clients and contractors. For instance, substituting new construction materials with salvaged or recycled products can reduce a project’s costs (Hwang & Bao Yeo, 2011). Likewise, the cost of disposal can be reduced if less waste is generated. Nagaraju, Reddy, and Chaudhuri (2012) observed that controlling waste volume is crucial to construction projects success. Waste minimisation as a company policy may allow organisations to present themselves as “environmental-friendly companies” (Hwang and Bao Yeo, 2011, p. 396), thereby promoting their services to potential and green clients. There are other benefits, including increased site safety, work efficiency, and job creation.

2.3.3 Obstacles to Construction Waste Minimisation Research has shown that waste management has become a global challenge (Hao, Hills and Huang, 2007). The obstacles impeding its implementation include legislative, social, economic, technical, and market barriers.

2.3.3.1 Legislative barriers

Government regulations and policies are essential tools for enhancing construction waste minimisation. Using Hong Kong as a case study, Tam (2008a) revealed that the compulsory waste management scheme for construction developments would influence the productivity of companies considerably. Shen and Tam (2002) further observed that legal measures for the implementation of environmental management on construction projects in Hong Kong are ineffective. Conversely, in Bulgaria, there is no clear differentiation between construction and municipal debris in the waste management policies, and as a result there is ambiguity in measures aimed at managing construction waste (Hadjieva-Zaharieva. Dimitrova, & Buyle- Bodin, 2003). Kartam, Al-Mutairi, Al-Ghusain, and Al-Humoud (2004) also reported that there are no clear rules compelling contractors to embrace sustainable construction in Kuwait, which may be responsible for a high volume of waste. Therefore, specific legislation or clear

regulatory policies about construction waste minimisation measures are important to reduce and divert waste from landfills.

2.3.3.2 Social barriers

Waste management is a low priority, despite the awareness of its importance among practitioners and stakeholders (Teo and Loosemore, 2001). Approximately 33% of material waste is caused by design choices (Poon et al., 2004; Innes, 2004). This is because designers pay little attention to waste reduction potentials when choosing building materials. Furthermore, de Guzmán, Villoria, Del Río, and Garcia (2012) observed that waste minimisation strategies are not exhibited in practice. Lam (1997) found that very few contractors had taken time to prioritise the environment and develop a system for waste management. This deficiency is due to the fact that contractors focused on project completion in the shortest possible time, instead of the environmental impacts of the project (Poon, Ann, & Ng, 2001). Similarly, Osmani et al. (2008) found the perception that waste is unavoidable as a potential barrier affecting efforts to minimise waste. Therefore, initiatives that will increase stakeholders’ social responsibilities will significantly drive the implementation of construction waste minimisation strategies.

2.3.3.3 Economic barriers

Many stakeholders are reluctant to embrace waste minimisation, citing cost concerns (Mills et al., 1999). Rewarding and penalising material handling on site can be an effective driver for practitioners to minimise waste (Chen, Li, and Wong, 2002). Previous studies (Park & Tucker, 2017; Ajayi & Oyedele, 2017; Adewuyi & Odesola, 2016; Osmani et al., 2008) have emphasised that monetary incentives could stimulate waste reduction during the construction process. Crawford, Mathur, and Gerritsen (2017) identified the lack of incentives (financial and non-financial) as one of the factors hindering construction waste management. Incentives can serve as motivators for effective waste minimisation.

2.3.3.4 Technical barriers

Chen et al. (2002) identified operatives’ lack of skill as being among the factors that contributes to a high volume of waste being produced. Waste resulting from construction activities, including off-cuts of formwork, poor block setting, poor plastering, and deformation during logistics could be reduced if operatives improved their skills (Wang, Touran, Christoforou, & Fadlalla, 2004). In addition, Osmani et al. (2008) observed that the majority of construction

practitioners lacked sufficient training on waste minimisation. Education and training are thus important in minimising material waste.

2.3.3.5 Dearth of advanced waste recycling market

A significant factor in material waste recycling is accessible markets for recycled products (Yuan, 2013; Jain, 2012; Yuan, Shen, & Wang, 2011; Mills et al., 1999). Bolden, Abu-Lebdeh, & Fini (2013) identified lack of markets to buy recycled materials as one of the factors for why companies do not use them. An underdeveloped market would require investment of time and money to establish relationships, keep track of market prices, and become credible material suppliers, thereby ensuring a continuous intake of construction materials. Hence, the dearth of an advanced waste recycling market will hinder effective implementation of waste sorting and segregation.

2.3.4 Framework for Construction Waste Minimisation This study proposes two frameworks for minimising material waste – Building Information Modelling (BIM) and the Circular Economy (CE). BIM is explained below while the CE is detailed in chapter three.

2.3.4.1 Building Information Modelling (BIM) According to the National Institute of Building Sciences (NIBS) (2007, p. 149), “BIM is a digital representation of the physical and functional characteristics of a facility”. Previous studies (Royal Institute of British Architects, 2012; Howell & Batcheler, 2010; Sabol, 2008) have observed that through an integrated database, BIM facilitates simulation of buildings and provides detailed information about design, elements, and quantities. It is regarded as a potential solution to complexities in the industry (Azhar, 2011) and could change professional boundaries (Olatunji, Sher, & Gu, 2010) while ensuring collaboration among stakeholders (Becerik-Gerber and Rice, 2010). Evidence suggests that BIM can possibly minimise material waste through effective communication and integration of design and construction (Gayathri, Himal, and Ranadewa, 2013; WRAP, 2013; O’Reilly, 2012; Sacks, Koskela, Dave, & Owen, 2010; Whyte, 2012). BIM enhances detailing, simulation and analytics, clash detection, and enhanced project efficiency regarding coordination and communication (Hardin, 2009; Eastman, Teicholz, Sacks, & Liston 2011; Krygiel & Nies, 2008). BIM enables users to explain or describe building components with data/parameters that can be used for analysis when generating designs or creating details to meet sustainable design specifications (Xie, Shi & Issa, 2010). The visualisation and simulation features of BIM are used by architects and

engineers to improve their design knowledge and increase their spatial cognition (Kim & Grobler, 2009). This gives project team members the advantage of evaluating their designs during early design phases through this feature (Yan, Culp, & Graf, 2011). Utilising 3D parametric models in BIM promotes effective communication between project stakeholders and helps contractors to accomplish an improved comprehension of construction processes and quicker decision making (Greenwood et al., 2008; Shelden, 2013). Despite these advantages, few studies have investigated the idea of using BIM to address waste generation in construction. One of these is a BIM tool developed by Cheng and Ma (2013) to estimate material waste. Similarly, Liu, Osmani, Demian and Baldwin (2015) developed a BIM-aided construction waste management framework that addresses design causes and assist architects to make appropriate decisions during the design phase. WRAP (2013), in an attempt to connect BIM with lifecycle phases of construction projects from conception to hand over, have developed procedures to improve and achieve resource efﬁciency by implementing BIM. Osmani (2013) also notes that BIM lacks decision-making tools to minimise construction waste during design. It is obvious from these studies that BIM has capabilities to reduce waste. Further studies are required on appropriate BIM technology or processes for minimising material waste.

2.3.5 Theory of Waste Behaviour (TWB) The TWB postulated by Teo and Loosemore (2001) hinges on the theory of planned behaviour (Ajzen, 1993). TWB explains construction professionals’ behaviour toward waste management by identifying three fundamental components – attitudes, subjective norms, and perceived behavioural control. Based on Teo and Loosemore’s (2001) argument, factors responsible for these components vary and are subjective. Factors such as few incentives, belief that waste is inevitable, scepticism about waste reduction, poor knowledge of residual values, consequences of waste, and methods and responsibilities for waste were identified (Teo & Loosemore, 2001). Hogg and Vaughan (2005, p.150) described an attitude as “a relatively enduring organisation of beliefs, feelings, and behavioural tendencies towards socially significant objects, groups, events, or symbols”. Attitudes are perceived as “evaluative judgement” (Crano & Prislin, 2006, p. 347) and can be described in three ways – affective, behavioural, and cognitive (McLeod, 2018). They are consistent with behaviour and are influenced by perceptions (Arif, Syal, Florez, Castro, & Irizarry, 2013; Rao, 2008). Since attitudes deal with people’s reaction and disposition about an object, they tend to be either positive or negative. Subjective norms relate to culture and, as described by Ajzen and Madden (1986, p. 454), cited by Strydom (2018),

37 they are the “perceived social pressure” required for behaviour, while social pressure is the “perceptions, beliefs, and judgements” of construction professionals (p. 3). Teo and Loosemore (2001) have identified factors responsible for subjective norms, which include pragmatic culture, wasteful culture, low management commitment, unclear policies, poor consultation, sense of inequality, low waste priority, unclear waste objectives, and inconsistent industry standards. Perceived behavioural control encourages positive waste management behaviours among professionals. It reflects trust in their capacity to execute waste management tasks and indicates the availability of resources and opportunities, which are independent of subjective norms and attitudes (Ajzen & Madden (1986) cited by Strydom (2018)). The factors responsible for perceived behavioural control are time and cost pressures, poorly design work processes, lack of waste facilities, lack of markets for waste, and impractical, inconvenient, and costly waste reduction efforts. The overarching aim of TWB is to encourage positive behaviour towards construction waste management. In support of TWB, Lingard, Graham, and Smithers (2000) emphasised the need for top management support and provision of local infrastructure in encouraging waste management. They also indicate the need for stakeholders, including construction firms, to imbibe waste minimisation culture. The texts consulted show that TWB is effective. Therefore, it is likely that its application in Nigeria should have similar results but it is yet to be tested.

2.3.5.1 Perception of Sustainable Construction As described previously (see Section 2.1.4), SC is the industry’s effort to achieve SD through appropriate implementation of SC principles at different phases. Understanding these concepts is pertinent for the implementation of SC because they inform stakeholders’ decisions. Construction professionals have the potential to provide sustainable buildings, but evidence shows that they lack understanding of sustainability (Jailani, Reed, & James, 2015). Their perceptions of sustainability vary (Du Plessis, 2001) and this impacts on the overall success of projects. Some professionals interpret sustainability as the management of a process, while others view it as a process on its own. Arif et al. (2013) concluded that perception is important in decision-making because it influences attitudes, which affects the behaviour of decision makers.

Perception of a situation varies among people because it is a personal interpretation that is unique to that individual. Contributory factors include attitudes, interest, motives, expectations, personality, and experience (Rao, 2008; Sharma, 2013). Previous studies (Du Plessis, 2007; Pitt, Tucker, Riley, & Longden, 2009) have shown that positive attitudes and behaviours enable

SC. Likewise, Gan, Zuo, Ye, Skitmore, and Xiong (2015) confirmed that professionals’ knowledge and understanding of SC principles, positive attitudes, and perceptions would promote SC, but identified misconceptions about sustainability as a major barrier in South East Asia. Similarly, Ashley, Blackwood, Butler, Davies, Jowitt, and Smith (2003) revealed that SC is difficult to implement because many professionals lack an understanding of sustainability, and Dania et al. (2007) also reported that Nigerian construction professionals have been unable to apply sustainable concepts. From these studies, it is clear that construction professionals have poor understanding, awareness, and perceptions of sustainability, which suggests the need for behavioural change to achieve SC and SD. However, behavioural change is a gradual process and should not be forced (O’Neill, 2010). To process this change, it is imperative to explore the awareness, attitudes, and perceptions of construction professionals to SC, including waste minimisation.

2.4 Nigerian Construction Industry The Nigerian economy benefits from the contributions of the construction industry (Figure 2.4) as revealed by the National Bureau of Statistics (NBS), (2015). Aibinu and Jagboro (2002) describe the industry as vibrant, occupying an important position, and stimulating economic growth. The early 1940s marked the beginning of an organised construction sector in Nigeria, with a small number of foreign companies (National Bureau of Statistics, 2015; Olowo-Okere, 1985). The industry experienced a massive boost between 1970 and 1983 due to the large production and sale of oil. Continued growth in the population has increased housing and infrastructure demand, ensuring the steady and significant growth of the construction sector.

All other sectors Financial and Insurance Construction Professional Services Real Estate

Activity Sectors Manufacturing Information & Communication Mining and Quarrying Trade Agriculture

0 5 10 15 20 25 30 35 % Contributions to GDP in 2017 Figure 2.4: Sectoral contributions to real GDP in Nigeria (2017) Source: Adapted from IMF, World Bank, FSDH Research Analysis, and NBS (2017)

During the second quarter of 2018, the industry grew by 44.09% in nominal terms, which represents 5.47% of the nation’s GDP (National Bureau of Statistics, 2018). The real growth rate was 7.66% (Figure 2.5), while in the second quarter of 2018 the contribution to real GDP growth was 4.51%, an increase from the previous quarter (National Bureau of Statistics, 2018). Nigeria was colonised by Britain for many years before it gained independence in 1960. The impact of colonial rule is still being felt in most aspects of the country, such as education, religion, economy, and others. For instance, the patterns, models, operations, and methods adopted in most industries today stem from colonial times.

The construction industry falls into this category as it was modelled on the British system, with some inclusions from other countries (Aibinu & Odeyinka, 2006; Mansfield et al., 1994). For example, the industry uses British Standards (BS) and British procurement methods, with the common procurement method being the traditional one (Ayangade, Wahab, & Alake, 2009). Some authors (Edmonds & Miles, 1984; Sonuga, Aliboh, & Oloke, 2002) have argued that these are not suited to developing countries because they do not consider local conditions. For instance, the Nigerian local content bill was passed in April 2014 showing the Nigerian government’s intention to encourage the use of local produce across all sectors. However, this legislation is yet to take effect in the construction industry although it has been adopted in the oil and gas sector.

Figure 2.5: Nigerian construction sector’s contribution to real growth Source: National Bureau of Statistics (2018).

Nigeria’s construction industry is made up of both indigenous and foreign contracting firms. Idoro (2009) claimed that foreign firms dominate the industry as only a limited number of local firms are operating. This was corroborated by the National Bureau of Statistics (2015). A survey conducted by Ugochukwu and Onyekwena (2014) on road contracts awarded by the Federal Executive Council between April and June 2009 revealed that 24.4% were awarded to indigenous firms and 75.6% to foreign firms. This may be due to the lack of capacity for human resource development needed for all stages of construction (Isa, Jimoh, & Achuenu, 2013). Nevertheless, Mbamali and Okotie (2012) suggest that if training institutions are improved, expatriates are engaged, local and foreign firms collaborate, government policies are enforced, and political terrain is stabilised, the difference in timely completion of projects between foreign and indigenous companies will be closed. Momoh (2011) reiterated that the construction industry is a target for many international firms due to the economic status of the country, which contributes to the growth of the sector and the nation at large.

The industry cannot survive without major stakeholders. The clients of major construction projects in Nigeria are at all levels of government (Federal, State, and Local) through ministries, parastatals, and agencies. Other clients include private individuals, companies, and organisations. Although some private individuals may be able to finance capital projects, most private projects are small scale (such as a single-family home unit). However, they still contribute to the industry. Small, medium, or large companies, as well as local, foreign, and multinational firms, patronise the industry for their commercial and retail construction needs. Other players in the industry include financial institutions, material suppliers, contractors, sub- contractors, design firms, professional bodies, and trade unions. With so many players involved, several challenges (discussed further in section 2.6) are likely to exist.

Figure 2.6 summarises Nigerian construction industry’s contributions to minimising waste. It indicates that factors such as the type of construction materials, demand and supply, competition, firm sizes, skilled and unskilled labour as well as challenges of the industry may contribute to waste generation. Conversely, regulatory framework including policies and regulations, professional regulations, development control agencies and opportunities of the industry are likely to contribute to waste minimisation. These factors are described in subsequent sections.

Figure 2.6: Nigerian construction industry and construction waste minimisation

2.4.1 Government Roles In the construction industry the government plays an important role. Aside from the general responsibility of developing human capital through the provision of educational services, there are other responsibilities that relate closely to the construction industry and/or built environment. According to Dantata (2007), they include: facilitating companies with access to capital, technology and factor inputs; encouraging the establishment of professional associations; demanding partnerships between foreign and local firms; and streamlining construction procurement processes. However, Dantata (2007) and Aibinu and Odeyinka (2006) revealed that these governmental responsibilities are seldom evident across the country. For instance, there is little or no partnership between foreign and local firms in delivering projects, as the former prefer to use their own labour. Chinese construction firms are a good example, wherein a majority of the labour force is Chinese (Babatunde & Low, 2013). From the foregoing, it is important that existing policies need to be more rigorously implemented.

2.4.2 Demand and Supply Urban areas in Nigeria are increasingly becoming overcrowded due to a massive influx of people searching for economic opportunities. According to the National Bureau of Statistics

(2018), about 51% of the population lives in urban areas. Similarly, the UN projects that by 2050 about 200 million people will live in Nigerian cities. The increasing urban population has had an understandably significant impact on the available infrastructure, which was not designed for such numbers and is becoming stretched, leading to overuse and/or shortages. For instance, housing provision in most urban areas is at a record low and, as estimated by the World Bank (2013), about 12 to 16 million housing units are needed. More so, the Federal Republic of Nigeria through the Federal Ministry of Land, Housing, and Urban Development (2014) observed that 15 to 23 million residential housing units are required to ease the shortage in urban areas. Therefore, there has been an increase in the demand for construction-related services and materials. There is a demand for offices, laboratories, factories, and other types of construction including roads and bridges across all sectors of the economy (Federal Ministry of Land, Housing, and Urban Development, 2014). Though this provides opportunities for the NCI to contribute to the country’s development, it may also generate a considerable amount of waste.

2.4.3 Competition Owing to the demand for construction services resulting from high population in urban areas, the industry has become highly competitive among indigenous and foreign construction firms (Oxford Business Group, 2015). Although foreign companies have dominated the industry (with the Chinese construction companies being new entrants), indigenous firms have emerged and are still emerging as strong competitors, especially for technical jobs that were once the speciality of the large European construction firms (Babatunde & Low, 2013).

2.4.4 Construction Materials Imported goods and services contribute around 12% of GDP (National Bureau of Statistics, 2015), which suggests that Nigeria depends heavily on imported goods. The construction industry is also reliant on imported materials, which may be a function of clients’ preferences. For instance, Dania (2016) observed that most imported construction materials are for finishes, and include furniture, paints, gypsum, and tiles. These are common materials that constitute waste on construction sites. Similarly, Olotuah (2002) revealed that the industry’s dependence on imported materials is responsible for high construction costs. Basic construction materials, including stone, timber, aggregates, and cement, are generally sourced locally. Some special cements are imported, but the majority of cement types are produced in Nigeria.

2.4.5 Construction Firm Sizes The sizes of construction firms in Nigeria may be categorised as small, medium, and large. Generally, large construction projects are publicly funded and attract companies with the necessary resources and credentials. As a consequence of being able to engage in these projects, large firms are usually profitable (Nnadi & Ugwu, 2014). The majority of indigenous firms fall within the small and medium scale and are mostly run as sole proprietorships. The different categories of firms shown in Table 2.5 have differing numbers of employees, annual turnover, equipment capacity, and/or assets, excluding land and buildings (SMEDAN, 2012; Oladapo, 2007a; Olaleye & Abdullah, 2014; Odediran, Adeyinka, Opatunji, & Morakinyo, 2012). Currently, no data are available on the number of firms in each category (as confirmed by the corporate affairs commission) (see Appendix E).

Table 2.5: Firm size distribution in Nigeria Firm sizes No of employees Annual turn over Micro and Small 1 – 49 < N5 million – N50 million Medium 50 – 199 N50 million – N199 million Large 200 and above N200 million above Source: SMEDAN (2012)

2.4.6 Skilled and Unskilled Construction Workforce Just like the manufacturing and production industry, the construction industry is dependent on labour, particularly both skilled and unskilled labour. The role of skilled and unskilled labour is vital, as they are actively involved in construction processes (Rafee, 2012; Medugu et al., 2011). In the construction sector, there is a shortage of skilled labour that has affected quality of work, profit, time, and productivity (Kuroshi & Lawal, 2014; Ruchi, 2012; Durdyev & Mbachu, 2011; Alinaitwe, Mwakali, & Hansson, 2007) resulting in large volume of waste. Similarly, Ugheru (2006) observed that skilled labour shortages in Nigeria are extreme. Some authors (Attar, Gupta, & Desai, 2012; Long, Ajagbe, Khalil, & Suleiman, 2012; Dantong, Lekjeb, & Dessah, 2011) have identified several factors responsible for skill shortages, including lack of training and retraining, poor image of the industry, ageing workforce, lack of government and industry commitments to promoting skill acquisition, and new skills for modern technologies. The industry is also reliant on unskilled manual labour (Idoro, 2012) for general site work, such as loading and off-loading materials, site cleaning, and equipment transfer. Unskilled labour is readily available due to the high unemployment rate in the country.

Some construction activities require unskilled labour and, according to Oyedele, Tham, Fadeyi, and Jaiyeoba (2011), this may impact on project quality, waste minimisation, timely completion of projects, raising concerns for firms in meeting client demands for high quality projects.

2.5 Opportunities for the Nigerian Construction Industry Across the globe, the construction industry is considered to be a potential driver of national economies. In Nigeria, the construction industry presents potential opportunities for improving the economy of the country. According to the National Bureau of Statistics (2015) the industry’s growth rate is 13%, which explains its contribution to the GDP, which is 7.17%. As at the second quarter of 2018, Nigeria’s GDP increased to N747, 860.30 million from N650, 767.19 million in the first quarter of same year (see Figure 2.). This is due to the Federal and State government’s substantial investment in infrastructure development, which has attracted foreign investors.

Figure 2.7: Nigeria’s GDP from construction Source: National Bureau of Statistics (2018).

As part of the government’s effort to provide infrastructure development, there are several ongoing mega construction projects across the country worth several billions of Naira (see Table 2.6). Policies, permits, and certifications, such as those required for guiding construction activities to achieve SD, have been enacted. These are the National Environmental Standards and Regulations Enforcement Agency Act, the Environmental Impact Assessment Act, the Biodiversity Conservation Permit, Air Quality Permit, Eco-Guard Certification, and Waste and Toxic Substances Permit. The construction industry provides opportunities to achieve sustainability through resource efficiency, waste management, and energy efficiency

(Sfakianaki, 2015). To achieve sustainability in the NCI, there is a need for a holistic framework that integrates economic, social, and environmental factors while considering the possibility of external influences such as political, legal, and technological changes.

Table 2.6: Ongoing mega construction projects in Nigeria

S/N Project Title Project location Project cost 1. Eko Atlantic City Lagos, Nigeria US$ 6 Billion 2. Abuja Millennium Tower Abuja, Nigeria US$333 Million 3. Lekki Free Trade Zone Lagos, Nigeria US$700 Million 4. World Trade Centre Abuja, Nigeria US$ 1 Billion 5. Federal Mass Housing Project (2,736 Across all States in Not available units) Nigeria 6. Renovation and upgrade of the Nnamdi Abuja, Nigeria N5.8 Billion Azikiwe International Airport Source: Adapted from Okafor et al. (2018)

2.6 Challenges for the Nigerian Construction Industry Nigeria currently faces many major challenges, including those that are technical, managerial, financial, and equipment-related (Ofori, 2001). These challenges span across clients, construction professionals, and government, and some of these are described in Figure 2.8. Based on the challenges, it is clear that the industry lacks commitment to research and developmental strategies that could contribute to the adoption and integration of new technology, innovation, and advanced methods of construction.

Figure 2.8: Challenges for the NCI 47

2.7 Regulatory Frameworks in the Nigerian Construction Industry Regulatory frameworks are legal requirements guiding the activities of an industry and providing the means of policing compliance of relevant legislation (Ruya, Chitumu, & Sharon, 2017). Although there are few regulations relating to the construction industry, there are permits and licenses. For instance, a construction permit must be obtained from the council before commencing any project. Depending on the project’s scale and its potential impacts, an Environmental Impact Assessment certificate may be required. During construction, the Urban and Physical Planning agency is required by law to inspect the project, while on completion a fire safety certificate is required. Likewise, there are regulations guiding activities of all professionals, while skilled workers are subjected to the terms and conditions of their respective contracts (Laws of Federal Republic of Nigeria, 2004, Chapter L1). However, the activities of skilled workers are guided by the Trade Union Act (Laws of Federal Republic of Nigeria, 2004, Chapter T14). According to Ruya et al. (2017), regulatory authorities for the construction industry are established to synchronise laws and policies, control planning and construction development, regulate activities of professionals, enhance compliance of building codes, and ensure smooth processing of planning approval. These have been reported to be inadequate in developing countries (Ofori, 2012). For instance, Nigeria relied on British Standards (BS) until 2006 when the national building codes were endorsed by the Federal Executive Council in 2017. Nevertheless, buildings have been and are still being constructed without reference to the building codes and standards (Dania, 2016).

2.7.1 Development Control Agencies The 1992 Nigerian Urban and Regional Planning Decree number 88 was Nigeria’s first development control act established by legislation to maintain standards and regulate land and building development. According to Ogunsesan (2004), the purpose of development control is to protect and enhance the built environment, coordinate land investments by private and public sectors while ensuring its effectiveness, and to control pollution. The power to control development is conferred on States, who regulate development within their jurisdiction through building bye-laws (Aluko, 2011). For instance, the Lagos State Physical Planning and Urban Development Ministry oversees the planning and development of all physical structures within the state through the Physical Planning and Development Authority, in association with Local Planning offices (Lagos State Government, 2017). Similar provisions operate in other States of the country to ensure effective development control across the nation.

2.7.2 Government Ministries, Departments, and Agencies There are 29 ministries in Nigeria and several departments and agencies within those ministries. A number of these are engaged with the construction industry. The Federal Ministry of Lands, Housing, and Urban Development, Federal Ministry of Works (FMW), and Federal Ministry of Environment (FME) are directly involved with the industry (see Table 2.7).

Table 2.7: Federal Ministries and their responsibilities

Type of Ministry Responsibility involvement Direct Federal Ministry of Lands, Housing, Responsible for preparing and monitoring and Urban Development government policies relating to national housing, urban development plans, and land use. Federal Ministry of Works Responsible for contract awards, procurement, construction, and maintenance of civil and heavy engineering projects for the federal government, including roads, dams, and bridges. The Federal Road Maintenance Agency (FERMA) responsible for maintaining all federal roads is one of many agencies under this ministry. Federal Ministry of Environment Responsible for developing and formulating policies to improve environmental quality and reduce environmental hazards such as pollution. The National Environmental Standards and Regulations Enforcement Agency is responsible for enforcing environmental legislation, including waste management. Indirect Federal Ministry of Industry, Trade Responsible for formulating trade and and Investment investment policies in all sectors of the economy Federal Ministry of Labour and Responsible for formulating policies on Productivity labour development Federal Ministry of Power Responsible for the establishment and construction of power plants, electricity, and hydro-dams for constant power supply. Federal Ministry of Science and Responsible for the advancement of Technology science and technology by supervising and controlling related policy developments Federal Ministry of Mines and Steel Responsible for providing information Development and knowledge that will assist investment (local and foreign) in the sector Source: Nexus Commonwealth Network (2019)

Based on the availability of regulatory frameworks, compliance and monitoring agencies, and Federal ministries involved with construction, Nigeria may be appropriately equipped for protecting the environment, enhancing economic sustainability, and improving quality.

2.7.3 Professional Regulatory Bodies Enforcement and regulation of professional conduct in the built environment lies with the professional regulatory bodies. Their statutory requirements are to set minimum educational requirements, issue practising licences, and ensure adherence to professional ethics and codes of conduct. By law, all professionals within the Nigerian built environment must have a relevant licence to practise. Their activities are controlled by regulatory bodies. For instance, the Architects Registration Council of Nigeria (Laws of the Federal Republic of Nigeria, 2004, chapter A19) is the regulatory body for architectural practice. The Council for the Regulation of Engineering in Nigeria (Laws of the Federal Republic of Nigeria, 2004, chapter E11) is the regulatory body for the engineering profession; the Quantity Surveyors Registration Board of Nigeria (Laws of the Federal Republic of Nigeria, 2004, chapter Q1) is the regulatory body for quantity surveying; while the Council of Registered Builders of Nigeria (Laws of the Federal Republic of Nigeria, 2004, B13) oversees the industry by ensuring standardisation and improvement of construction techniques and materials, training and certification of skilled workers, including site supervisors, and registering of contractors.

2.7.4 Construction Policies and Regulations 2.7.4.1 National Policy on Environment Nigeria’s first national environmental policy was formulated in 1991, revised in 1999 and is yet to be reviewed despite the dynamic nature of the environment. The national policy aims at managing the environment and natural resources with due consideration for sustainable development (Kankara, Adamu, Tukur & Ibrahim, 2013; Eneh & Agbazue, 2011). The provision of several objectives and guiding principles (such as the “polluters pay” principle), may contribute to achieving the the purpose of the policy. Section 4.3 of the national policy on environment mentions human settlements, housing, and general construction, while section 4.6 deals with the effective use of land and conservation of soil (Federal Environmental Protection Agency, 1989). Ajayi and Ikporukpo (2005) criticised section 4.3 for its lack of consideration for construction-related pollution. The section concentrates on oil-related spills and desertification. There has been significant achievement in these sectors, as evident in the 2018 global results of the environmental performance index – a global metric that measures “how close countries are to established environmental policy goals” (Environmental Performance

Index, 2018). The result ranks Nigeria 100th out of the 180 countries surveyed. This is an improvement compared to a position of 133rd out of 190 countries surveyed in 2016. Although this indicates improvement, there is still a need for enforcement of existing environmental policies and formulation of construction waste minimisation policies.

2.7.4.2 National Building Code A building code is described as a collection of rules that describe the minimum standards required to ensure safety and quality of buildings and non-building structures (Taiwo, 2011). In Nigeria, the National Building Code (NBC) is a set of rules and principles formulated to guide the activities of construction professionals (Federal Republic of Nigeria, 2006). Prior to the first NBC in 2006, the construction industry relied on British Standards for standardisation and regulations. After several workshops held in Ogun, Lagos, and Port Harcourt in 1990, 1998, and 2005 respectively, the NBC was developed, with inputs from all construction professionals. It was reviewed in 2013 and finally approved in 2017. The reasons for the code as indicated by the Federal Republic of Nigeria (2006) include: lack of planning in cities and towns; disasters including building collapses, fire, and abuse of use; lack of certified design criteria for professionals; continuous use of unrefined products and materials; and dearth of suitable regulations and penalties for non-compliance. The NBC is divided into four sections, as shown in Table 2.8. The scope of the code covers matters relating to design, construction, usage, maintenance and demolition of building structures. Strict adherence should ensure the safety and quality desired. A review of the NBC, however, indicates that it does not address sustainability (Dahiru, Dania, & Adejoh, 2014) and does not make provisions for energy efficient designs and use of low carbon materials (Dania, 2016). In addition, the code makes no mention of construction waste management requirements – an important aspect of sustainable development. Therefore, Dahiru et al. (2014) have suggested a review of the code to incorporate sustainability options that would contribute to achieving SD.

Table 2.8: Sections of the National Building Code

Parts Descriptions Part I Administration (Sections 1 -3) Part II Classification and Requirements (Sections 4 – 12) Part III Enforcement (Section 13) Pre-design Stage Design Stage Construction Stage Post-Construction Stage

Part IV Schedules (Section 14 – 15) Source: Adapted from the National Building Code (Federal Republic of Nigeria, 2006)

2.7.4.3 Local Content Act Although application of the local content act is being considered in the construction industry, this legislation has been mainly applied in the oil and gas industry. It is commonly known as the Nigerian Oil and Gas Industry Content Development Act 2010. “The Act seeks to increase participation in the oil and gas industry by prescribing minimum thresholds for the use of local services and materials and to promote transfer of technology and skill to Nigerian staff and labour in the industry” (Akindelano, 2018). It aims to promote local participation and grant indigenous companies exclusive considerations for executing jobs in the industry. In addition, the Act is applicable to all entities involved in the oil and gas sector, comprising operators, regulatory authorities, contractors, sub-contractors, and alliance partners. While the level of enforcement is unknown, the Nigerian Content Development and Monitoring Board has been set up to implement the Act’s provisions. Conversely, the NCI has proposed a similar act modelled after the Nigerian Oil and Gas Industry Content Development Act to encourage participation of indigenous companies in construction projects, use of local materials, labour, and suppliers, technology transfer, and effective utilisation of local professionals (Ezugwu, 2014). Although the proposed Act is under consideration by the legislative arm of government, it has been criticised for lack of clarity, distinguishable targets, and characterisation of the industry (Fernz, Hawkins, Matthews, & Wells, 2013). It has since been undergoing modifications and is still to be passed into law.

2.7.4.4 National Environmental (Construction Sector) Regulations The National Environmental Standards and Regulations Enforcement Agency was established as part of the government’s efforts to preserve the environment, safeguard and improve ecosystem, conserve biodiversity, ensure SD of natural resources, and advance environmental technology (National Environmental Standards and Regulations Enforcement Agency, 2018). In addition, the National Environmental Standards and Regulations Enforcement Agency is authorised to:

“enforce compliance with laws, guidelines, policies and standards on environmental matters, coordinate and liaise with stakeholders within and outside Nigeria on matters of environmental standard, regulations and enforcement, and enforce compliance with the provisions of international agreements, protocols, conventions and treaties on the environment” (National Environmental Standards and Regulations Enforcement Agency, 2018).

Between 2009 and 2010, the agency developed 24 new environmental regulations with the support of the federal government. The National Environmental (Construction Sector) Regulations relate directly to the construction industry, with the aim of preventing and minimising pollution arising from construction, decommissioning, and demolition activities (National Environmental Standards and Regulations Enforcement Agency, 2018). It addresses issues in the industry such as stormwater drainage, site waste management plans, toxic emissions, asbestos, and noise control. Dania (2016) has criticised the regulation for lacking specificity, arguing that some provisions are ambiguous. Specifically, Dania noted ambiguity in the meaning of ‘construction facility’ and ‘best available technology’. A comprehensive review of the regulation is important to ensure clarity of provisions.

2.8 Path to Sustainable Development 2.8.1 Sustainable Development Goals The Sustainable Development Goals (United Nations, 2015b) emerged as a collective appeal by countries to protect the environment, end poverty, and ensure peace and justice. Following the successes of the Millennium Development Goals, 17 interconnected sustainable development goals were developed. The construction industry plays a significant role in achieving some of these goals. For instance, good health and wellbeing (goal 3); clean water and sanitation (goal 6); affordable and clean energy (goal 7); decent work and economic growth (goal 8); industry, innovation and infrastructure (goal 9); sustainable cities and communities (goal 11); responsible consumption and production (goal 12); climate action (goal 13); and life on land (goal 15) are all related directly or indirectly to construction activities. The voluntary national review of 2017 (UN, 2017) indicates that Nigeria is making appreciable progress in achieving these goals, but challenges such as heavy reliance on oil and gas, dearth of infrastructure and technological gaps, and economic and humanitarian crises are hindrances. Specific areas requiring urgent support to implement sustainable development goals are mobilising adequate financial resources, technology transfer, capacity building, data, information, and performance management (UN, 2017). Therefore, there is a need for industries, including the construction industry, to explore various options to proffer solutions to these areas and challenges.

2.8.2 Vision 20:2020 The vision 20:2020 was conceived as part of the government’s efforts to improve economic conditions. It is an economic draft to strategically position Nigeria in the world’s first 20 economies, based on a GDP of at least US$900 billion by year 2020 (National Planning

Commission, 2009). This vision focuses on environmental, institutional, and economic dimensions based on three pillars, which are: “guaranteeing the productivity and wellbeing of the people; optimising the key sources of economic growth; and fostering sustainable social and economic development” (Adeagbo, 2013, p. 353). Approximately US$510 billion worth of investments in infrastructure are required to achieve the vision, as suggested by the Central Bank of Nigeria (Dania, 2016). The role of the construction industry then becomes vital in providing the required infrastructure.

2.8.3 National Environmental Summit To advance the cause of SD in the country, the federal government, through the Ministry of Environment, organised the first national environmental summit in October 2008. Participants were drawn from federal ministries, state governments, academia, civil organisations, and international organisations such as United Nations Development Programme (UNDP). The summit focused on raising awareness of the impacts of SD on national development. It provided an avenue for participants to discuss the challenges and suggest possible ways to combat environmental issues. None of the themes discussed the environmental impacts of construction activities. Although the summit was appropriate, subsequent summits may include issues affecting the construction industry, such as waste minimisation, as part of the themes.

2.9 Summary Construction, being a project-based activity is involved with processes and operations conducted in phases whose outputs are important to achieving SD. Evidence shows that the activities of the construction industry generate waste and consume resources. The industry’s response to these challenges is SC, which encompasses waste management, resource efficiency, and energy conservation. The adoption of SC principles at the design, procurement, and construction phases is vital for SD. Efforts to manage construction waste have been documented, including identification of waste sources, causes, types, and minimisation strategies. The sources of waste depend on construction activities, site conditions, and practises. The causes of waste are categorised as design, handling, external factors, workers, management, procurement, and site conditions. Similarly, waste types are grouped as physical and non-physical, whereas material composition varies but includes wood, metal, concrete, glass, stones, and plastics. While waste management efforts ensure appropriate disposal after waste has been generated, waste minimisation strategies reduces the volume of waste generated. Construction waste minimisation strategies that have been employed were categorised based on construction phases (design, procurement, and construction) and

legislative measures. Factors responsible for waste minimisation were categorised as environmental, economic, institution, human, and legislation, while there are several benefits, including cost savings, improved resource management, and reduced demand for landfill spaces. Conversely, obstacles were categorised as social, economic, legislative, and technical barriers. The discussion around construction waste minimisation was streamlined to Nigeria and an overview of the construction industry was provided. The NCI is divided into formal and informal sectors, while the major clients are government at all levels, private individuals and organisations. The industry is made up of foreign and indigenous contracting firms, with the former dominating the scene. Furthermore, the industry makes a significant contribution to Nigeria’s GDP and ranks 5th of all other sectors of the economy. Several characteristics of the industry, such as demand and supply, competition, materials, firm sizes, being capital intensive, and labour were highlighted. Although opportunities for the industry that provide the possibility to achieve SC and SD were identified, notable challenges and barriers, including lack of synergy, poor management, and project abandonment, were identified and discussed. While there are challenges, the government’s effort to ensure compliance with regulations is reflected in the responsibilities of development control agencies, government ministries, departments and agencies, professional regulatory bodies, and construction policies and regulations, including national policy on environment, NBC, local content act, and national environmental (construction sector) regulations. In addition, the government’s commitment to achieving SD is evident it its vision 20:2020 goals, sustainable development goals, and national environment summit. It is contended that the nation needs to do more. For effective waste minimisation, the review suggests the need for a holistic waste minimisation framework that would integrate SD principles, all phases of construction, and legislative measures.

The following chapter reviews the circular economy concept. It provides a synopsis of the CE concept, its schools of thought, practical applications, implementation, assessment, relationship with SD, and its adoption in the construction industry.

CHAPTER THREE THE CONCEPT OF CIRCULAR ECONOMIES

3.0 Overview In chapter one, the study discussed the research problem and identified gaps in the literature to justify why the research was conducted. The aim, objectives, scope and limitations of the study were also identified, leading to a review of literature in chapter two. Construction and SD concepts, including waste management, form part of the review. In addition, the concept of waste and minimisation measures were discussed, while an overview of the NCI, including opportunities, challenges, regulatory frameworks, and paths to SD, were reviewed. Collectively, these lead to the introduction of the CE concepts.

Chapter three reviews the circular economy (CE). There are several studies on the application of the CE concept in industry, including manufacturing, steel, agriculture, and textiles. It is gaining traction in the construction industry due to its potential as reported for other industries. To ensure clarity about the CE, this chapter provides a general overview of the concept before relating it to the construction industry. This chapter starts with a review of the origins of the CE, its definition, principles and characteristics. The background of the CE, including biomimicry, industrial economy, cradle to cradle, and regenerative design, is discussed, as well as the comparison between these pillars. Subsequently, the transition to the CE through different approaches, such as product design, business models, reverse networks, enabling conditions, tools and techniques as well as top-down and bottom-up approaches are explored.

This chapter also reflects on the practical application of the CE including its implementation, policies, models, and strategies, which are discussed followed an assessment of the CE, revealing its benefits, drivers, challenges, and criticisms. The overarching aim of the CE (sustainable development) are described by highlighting its environmental, social, economic, and technological impacts. Subsequently, behavioural impacts on the CE are described. This is followed by a review of the opportunities for circularity and approaches to the CE in the construction industry. The last section justifies the study’s adoption of diffusion of innovations theory as the philosophical underpinning to the implementation of the CE concept in the building construction industry. Overall, literature on the CE has been reviewed to provide the basis for its application in the construction industry.

3.1 The Circular Economy Concept To understand the CE concept, it is important to briefly explore the linear economy concept. According to the Ellen MacArthur Foundation (EMF) (2013a), the linear economy is the “take- make-dispose” approach in which natural resources are extracted for the production of products that are disposed of after use. Problems associated with this approach include high resource pressures, huge waste generation, high energy use, and environmental pollution (Shi et al., 2006; Xinan & Yanfu, 2011; Yuan et al., 2006). Although some resources such as timber can be replaced once extracted, others such as copper, iron, and bauxite can never be replaced, and that will eventually lead to a scarcity of natural resources. The linear concept has been described by some authors (Shi et al., 2006; Xinan & Yanfu, 2011; Yuan et al., 2006) as unsustainable, and can be likened to traditional methods of construction where material waste generated during construction processes is sent to landfill. In some countries, the linear approach still dominates the construction industry. In Nigeria, the activities of the industry have detrimental effects on the environment (Abidin, 2010; Dania, Kehinde & Bala, 2007), while in Europe it consumes about half of the entire natural resources (European Commission, 2001). This indicates that the linear model is unsustainable as it does not reuse and recycle in economic terms (Jackson, Lederwasch, & Giurco, 2014; McDonough & Braungart, 2002). This highlights the need for a model that is economically, socially and environmentally sustainable.

Several authors have proposed the CE concept as a sustainable model to replace the linear model. The CE is a model wherein resources are extracted to manufacture products that are regenerated at their end of lives and returned into the economy (Guohui & Yunfeng, 2012). This approach provides solutions to the contemporary consumption and production of materials and hinges on the principle of the earth being a closed system linking the environment and the economy in a circular relationship (European Commission, 2014c). The CE origin, principles, drivers, benefits and challenges are explored below to provide insight into its potential application in the construction industry.

3.1.1 Origin of the Circular Economy According to Murray et al. (2017), the origin of the CE cannot be traced to a particular author(s), publication, or year (Damen, 2012). It has its root mainly in ecological and environmental economics and industrial ecology (Ghisellini et al., 2016; Murray et al., 2017; Preston, 2012) and originates from eco-industrial development (EID) theory (Geng, Fu, Sarkis, & Xue, 2012) and general systems theory developed by Von Bertalanffy (1950, 1968). Murray et al. (2017) claimed that its antecedents are found in broader economic, historical, and

ecological fields. Similarly, Qian and Wang (2016) note that the CE can be traced to environmentalism. It is also rooted in some schools of thought and theories that are critical of the linear economy (Allwood, 2014; Ellen MacArthur Foundation, 2013b; Preston, 2012). One such theory is the spaceship theory postulated by Professor Kenneth E. Boulding, an American economist, which is explained below.

Kenneth E. Boulding is acclaimed by researchers (George, Lin, & Chen, 2015; Ghisellini et al., 2016; Greyson, 2007; Persson, 2015; Rizos, Behrens, Kafyeke, Hirschnitz-Garbera, & Ioannou, 2015) as the originator of the CE concept. He developed the embryonic idea in his article titled: “The Economics of the Space Ship Earth” (George et al., 2015), where he described the earth as a single spaceship on a voyage with a pre-loaded stock of resources. As the journey progresses, the resources are depleted unless they are recycled. This implies that man is consuming the earth’s limited resources without replacing them. He suggested that “man must ﬁnd his place in a cyclical ecological system which is capable of continuous reproduction of material form even though it cannot escape having inputs of energy” (Boulding, 1966, pp. 7-8). His idea was to promote a shift from the “open system” to a “closed system” where there would be continuous production and consumption with durable products. He asserted that, “we have underestimated, even in our spend thrift society, the gains of increased durability” (Boulding, 1966, p. 12). This idea “is seen as a prerequisite for the maintenance of sustainability of human life on earth (a closed system with practically no exchanges of matter within the outside environment)” (Ghisellini et al., 2016).

The idea of a closed system was further developed by Stahel and Reday-Mulvey in 1976 into the “closed-loop economy” that relies on improved durability (Murray et al., 2017). This term has been used interchangeably with the CE. For instance, Mathews and Tan (2011) referred to it as a closed-loop, suggesting a mutual relationship. Similarly, Yang and Feng (2008, p. 813) described the CE as an “abbreviation of [a] closed materials cycle economy or resource circulated economy”. The term circular economy was, however, coined by David Pearce and R. Kerry Turner, two British environmental economists, in 1990 (Qian & Wang, 2016; Su et al., 2013). In their book, titled “Economics of Natural Resources and the Environment”, they noted that the linear economy treats the environment as a waste pool due to its inability to recycle (Su et al., 2013). However, the CE recognises the effectiveness of resource cycling (Preston, 2012). Based on current evidence, the origin of the CE is presented chronologically in Figure 3.1. The CE is currently receiving unabated attention in China, United Kingdom, European Union, Japan, Scotland, Finland, and Austria. It is now clear that the CE is yet to be

widely practiced (Andrews, 2015). However, some of the reasons why it has not been implemented are identified and discussed in section 3.5.3.

Space Ship Circular Rethink the Theory • 1976 Economy • 2009 future • 1950 • 1966 • Stahel & Reday- • 1990 • China • 2012 • Von Bertalanffy • Kenneth E. Mulvey • David Pearce • Ellen McArthur Boulding & R. Kerry Foundation General System Closed Loop Turner CE Promotion Theory Economy Law

Figure 3.1: Chronological order of the CE origin

3.1.2 Definition of the Circular Economy The CE lacks a commonly accepted definition (Rizos et al., 2017; CIRAIG, 2015; Bechtel, Bojko, & Völkel, 2013, Damen, 2012), which may be responsible for its low adoption rate (Andrews, 2015). Kirchherr, Reike and Hekkert (2017) argue that the concept of CE may become obsolete because different definitions of the term give rise to different interpretations. Similarly, Liu, Li, Zuo, Feng, and Wang (2009) examined public awareness in the promotion of CE in China and found that 58.2% of the participants had recently heard of the CE while 29% had never heard of it. There are several definitions of the CE that are founded on individuals’ perceptions, and these are presented in Table 3.1. The commonest definition of the CE is “an industrial system that is restorative or regenerative by intention and design; aims to rely on renewable energy; minimises, tracks, and eliminates the use of toxic chemicals; and eradicates waste through careful design” (Ellen MacArthur Foundation, 2013a, p. 22). As a system, the CE focuses on closing the loop for materials and energy flows while contributing to long-term sustainability (Ellen MacArthur Foundation, 2013b), thereby ensuring materials and energy are kept in a circular flow. Liu (2012, p. 256) provided a detailed definition of the CE as “an economy system which is characterised by [the] principle of sustainable growth and depends less on depletion of natural resources than traditional economies through the mechanism of recycling the waste output of its system”. This shows a possible and strong CE- sustainable development connection, which was confirmed by Li’s (2012) description of the CE as an economic growth model that protects the environment, prevents pollution, and achieves sustainable development (SD).

Table 3.1: Definitions of the CE

Source Definition Prieto-Sandoval, Jaca, The CE is “an economic system that represents a change of paradigm in and Ormazabal (2018, the way human society is interrelated with nature and aims to prevent the p. 610) depletion of resources, close energy and materials loops, and facilitate sustainable development through its implementation at the micro (enterprises and consumers), meso (economic agents integrated in symbiosis) and macro (city, regions and governments) levels”. Wysokińska (2016, p. The CE is a “closed loop economy” that generates little waste, which 1) become a resource. Ellen MacArthur The CE “is restorative and regenerative by design and aims to keep Foundation (2015a, p. products, components, and materials at their highest utility and value at 2) all times, distinguishing between technical and biological cycles”. Accenture (2015, p. 1) The CE is a system “where growth is decoupled from the use of scarce resources through disruptive technology and business models based on longevity, renewability, reuse, repair, upgrade, refurbishment, capacity sharing and dematerialization”. Zhijun and Nailing The CE is “a mode of economic development based on ecological (2007, p. 95) circulation of natural materials, requiring compliance with ecological laws and sound utilisation of natural resources to achieve economic development”. Yap (2005, p. 13) The CE is a “scientific development model where resources become products, and the products are designed in such a way that they can be fully recycled”

From these definitions, it can be deduced that the CE is aimed at protecting the environment, preventing waste, reusing resources and recycling waste. These are the central themes of these definitions. Some authors have addressed the CE as a model, concept, system, generic term, and as a sustainable approach (Table 3.2). Their differing interpretations enrich understanding of the CE. Conversely, Masi, Day, and Godsell (2017) argue that the definition of the CE should be broad and all-encompassing, being a new social and economic paradigm. Therefore, a general definition of the CE should reflect its central themes, purpose, principles, and sustainable business models (Kirchherr et al., 2017). According to Gladek (2017), no single group is authorised to define the CE and, as such, most definitions are subjective (Kirchherr et al., 2017). The following CE definition is therefore proposed: a sustainable concept that ensures zero waste of materials, low pressure on resource consumption and energy through reuse and recycling principles.

Table 3.2: Descriptions of the CE in literature

Description of CE Author(s) and year Model Van den Berg and Bakker (2015), Yap (2005), Li (2012), Murray et al. (2017) Concept Andersen (2007), Geng et al. (2012), Iung and Levrat (2014), Wang and Simeone (2005) System Stahel (2010), Charonis (2012), Dorn et al. (2010) Generic term CCICED (2008), Jun and Xiang (2011), Wilson (2015) Sustainable approach Geng, Zhu, Doberstein and Fujita (2009), Guohui and Yunfeng (2012), Li (2012), Xue et al. (2010), Qian and Wang (2016), Si-yuan and Yuan (2012), Kai (2004); Preston (2012) Paradigm Ghisellini et al. (2016); Masi et al. (2017)

3.1.3 Principles of the Circular Economy The Ellen MacArthur Foundation (2015a, p. 5) submits that, “the concept is characterised, more than defined, as an economy that is restorative and regenerative by design and aims to keep products, components, and materials at their highest utility and value at all times”. The philosophy of the CE has been explained by several authors through its principles. The EMF, being an advocate for the transition to the circular economy, described its principles as being to:

• “Preserve and enhance natural capital by controlling finite stocks and balancing renewable resource flows” ( Ellen MacArthur Foundation, 2015a, p. 5). • “Optimise resource yields by circulating products, components, and materials at the highest utility at all times in both technical and biological cycles” Ellen MacArthur Foundation, 2015a, p. 7). • “Foster system effectiveness by revealing and designing out negative externalities” Ellen MacArthur Foundation, 2015a, p. 7).

Similarly, Damen (2012, p. v) argues that the CE relies on four main principles that are derived from three schools of thought (Design for Environment, Cradle to Cradle and Industrial Ecology). They are:

• “The redesign of products and production processes so they can operate in closed loops with a minimal or zero impact on the environment and human health”. • “The improvement and creation of end-of-life systems for flows of resources and products”.

• “The creation of, preferably regional, networks of material exchange”. • “The collection, management and exchange of resource-related information”.

Damen (2012) further argued that the first three principles rely solely on the last. This indicates that the last principle is the first priority. However, some authors differ as to the basic principles of CE. They claim that the 3R’s (Reduce, Reuse and Recycle) are the principles of the CE (Preston, 2012; Sakai et al., 2011; Su et al., 2013; Zhijun & Nailing, 2007; Ren, 2007; Reh, 2013; Lett, 2014). In support of their claim, Ghisellini et al. (2016) note that the CE is referred to in literature through the 3R principles, which can be integrated into those developed by the Ellen MacArthur Foundation. Pan et al. (2015) have embellished the claim of Ghisellini et al. (2016) by adding two more R’s, to make it 5R (Reduction, Reuse, Recycling, Recovery and Reclamation). Further studies on the CE have added three more R’s (Recover, Redesign, and Remanufacture) (Govindan and Hasanagic, 2018). Ren (2007) attests to the effectiveness of these principles when implementing the CE in practice, suggesting that they are important for its successful application (Shi et al., 2006). According to Zhu and Qui (2008), the 3R principles are embedded in production and consumption, since materials and energy flow are consumed in both. Therefore, all CE principles are interwoven and similar but are referred to differently. The relationship between them is presented in Figure 3.2, highlighting that the 3Rs are the core principles. Hierarchically, the reduction principle leads others in the whole process of a CE system (Su et al., 2013). However, the 3Rs are mutually exclusive and are of great advantage when applied throughout the entire production process.

The reduction principle is concerned with resource and energy input in the production and consumption processes (Ren, 2007; Su et al., 2013). Ghisellini et al. (2016) refer to this principle as eco-efficiency, whose aim is to improve production efficiency by minimising waste, raw materials and energy input. In the same vein, Liu (2012) asserts that reduction is an efficient method where input of materials is reduced so that efficiency can be increased. This was corroborated by Zhijun and Nailing (2007) and Su et al. (2013). Examples of the reduction principle include simplified packaging, improved technologies, compact or lightweight products, and reduction in volume (Damen, 2012; Ghisellini et al., 2016; Su et al., 2013). The benefits of applying reduction principles, especially at the design stage, are numerous. For instance, it could save raw materials by reducing “bill of materials, standardisation, and modulation of components, simplified products and packaging” (Gaspar, Julião, & Tjahjono, 2018, p.123). Numerous environmental benefits (EEA, 2016), including reduction of greenhouse gas emissions and air pollution, are also attributed to the reduction principle, while

low consumption, low emission, and high energy efficiency may be achieved (Wang, Li and Tam, 2014).

Figure 3.2: The CE principles Source: Adapted from Ellen MacArthur Foundation (2015a, p. 5-8) and Damen (2012, p. v)

The reuse principle, as described by den Hollander et al. (2017, p. 518), is “any operation by which products or components that are not waste are used again for the same purpose for which they were conceived”. It may also involve direct re-sale of product parts (JRC 2011) and could be referred to as a principle associated with processing and effective use of natural resources (Shi et al., 2006). Materials are reused to avoid waste, and reduce resource extraction and energy. Thus, waste or by-products from one company may serve as raw materials or resources for another. This has several environmental benefits compared to the production of new materials, as less energy, fewer resources, and less labour is required (Castellani, Sala, & Mirabella, 2015; James, 2011). Reuse could revive local economies while contributing to the reduction of environmental impacts such as emission of toxic substances (Castellani et al., 2015; Stahel, 2013). In addition, it could reduce cost and energy by 40% and 80% respectively (Circulair, 2015). However, Liu (2012) has advocated an integrated system which would depend less on virgin resources and reused resources at the processing stage. This could reduce dependence on raw materials and extend product life and service validity (Su et al., 2013). Stahel (2013) has emphasised reuse as the leading CE principle, while Shi et al. (2006) stated that reuse of products will lengthen a product’s life span and minimise waste generated at the

production stage. Su et al. (2013) stressed that frequent maintenance of reused products is necessary to ensure durability. This suggests that maintainability of materials should be considered at the design or production stage to enhance continuous usage. Ghisellini et al. (2016) suggest that reuse and disassembly of materials would be possible with better design of products and business models. Likewise, successful implementation of the reuse principle would depend on consumers’ willingness to use second-hand materials (Stahel, 2013). This would require the development of used material standards, additional efforts such as marketing (Watson, 2008), education and training as well as a shared responsibility among stakeholders (Lenzen. Murray, Sack, & Wiedmann, 2007).

According to Van den Berg and Bakker (2015), recycling is the last option for recovering the end-of-life value of a material. Being the third principle of CE, it involves reprocessing of materials assumed to be waste into new materials or products for further use either for their original purpose or other purposes (Ghisellini et al., 2016). It is adopted “when a product can no longer be recovered from obsolescence in its current form, but must be broken down into its constituent materials, which then regain value with a diﬀerent function” (Kane, Bakker, & Balkenende, 2018, p. 39). It is thus clear that recycling is a recovery operation (Ghisellini et al., 2016) to reproduce waste as a useable material, part of the original or another product, and a raw material for entirely new products (Shi et al., 2006). Ren (2007) described recycling as a critical step in translating waste into resources. Shi et al. (2006) encourages both producers and consumers to use secondary resources and buy products made from secondary resources. In addition, George et al. (2015) described a microeconomic model which places recycling at the forefront of developed CEs.

Murray et al. (2017) has asserted that recycling is fundamental to the CE because its waste reduction characteristics have long been proven to be effective. Similarly, Van den Berg and Bakker's (2015) claim that recycling is mandatory for products to contribute to the CE supports Murray et al.’s. (2017) assertion. Recycling helps reduce the use of virgin materials (Shi et al., 2006; Su et al., 2013; Jun & Xiang, 2011), and reduces waste (include useable and potential materials) (Birat, 2015; Dajian, 2008; Lazarevic, Buclet, & Brandt, 2012). Circulair (2015) report that recycling reduces cost by 10% and energy use by 50%. In addition, several researchers (Cagno, Trucco, & Tardini, 2005; Lazarevic et al., 2012, Birat, 2015) have confirmed that recycling offers opportunities to beneﬁt from usable materials by reducing waste quantities, thereby decreasing environmental impact such as pollution. Materials such as metals can be recycled many times (Reh, 2013), while contaminated materials are not

recyclable (Prendeville, Sanders, Sherry, & Costa, 2014). Other materials (such as expanded polystyrene) may experience low levels of recycling (UNEP 2013; Prendeville et al., 2014), which indicates that only some products can be recycled economically. Therefore, source identification of waste, design for disassembly, and material sorting are essential for recycling. In addition, recycling is essential for the CE (Van den Berg & Bakker, 2015) and should form part of the CE (Birat, 2015; George et al., 2015).

Despite its advantages, recycling has been criticised for negatively impacting the environment. For instance, Bartl (2015) argued that it reduces a product’s efficiency and quality. Consequently, den Hollander et al. (2017) concluded that it is the least preferred option among the CE principles. In addition, it consumes considerable energy (Moreno et al., 2015; European Union 2008). Therefore, alternative source of energy may be considered. Furthermore, recycling of materials at their end-of-life has to be carefully considered and incorporated at the design phase, especially if a product is to be used for different purposes. This should ensure smooth reprocessing of materials and maximise their value.

3.1.4 Characteristics of the Circular Economy The characteristics of the CE have been reviewed and found to revolve around waste reduction, decoupling of economic growth from environmental pollution, and value creation (Ellen MacArthur Foundation, 2015a). Li and Li (2008) identified three notable characteristics of the CE – the source-economised economy, ecological economy, and hi-tech economy. They described the source-economised characteristic as the effort to minimise use of new materials at the production stage, thereby allowing reuse and recycling to ensure a closed-loop. They explained ecological economy characteristic as the collaboration between different industries, forming an ecological chain where waste from one serves as resource for the other. This reduces waste generation, creates harmony between industries, mankind, and nature while ensuring economic growth. The hi-tech economy characteristic of the CE was described by Li and Li (2008) as the ability to reduce the use of virgin materials and energy to achieve high production and low pollution through the adoption of new techniques and technology.

In the same way, Yunyan and Biao (2014) identified three main features of the CE, the first being resource reduction, which could only be realised through dependence on “large-scale production to reach economy of scale” (p. 50). The second characteristic is that its technical requirements are high, while the third indicates that the CE is a concept with benefits for individuals, organisations, and communities (Yunyan and Biao, 2014). Li and Chai (2007, p.

361) also identified three main characteristics, which are “low investment and high efficient utilisation of natural resources and low discharge of water”. The Ellen MacArthur Foundation (2013a; 2015a) provided five fundamental features of the CE – designing out waste, building resilience through diversity, relying on energy from renewable sources, thinking in systems, and thinking in cascades, which are described in Table 3.3. Other characteristics include low material and resource consumption, low levels of pollution, high efficiency, high circulation rates, and judicious use of resources (Jun & Xiang, 2011). These highlight the CE as an important system applicable to the construction industry, and capable of delivering SD.

Table 3.3: Characteristics of the CE

CE characteristics Description Design out waste • Design and optimisation of biological and technical components (Figure 3.3) for a cycle of disassembly and reuse. • Biological products (food or wood) are non-toxic and can be composted (Figure 3.3) and are designed for safe re-entry into the biosphere. • Technical materials (polymers, alloys and other man-made materials such as tools, fixtures, fittings etc.) are designed to use minimal energy, retain maximum value for quality, and have reuse capabilities. • The concept of end of life (disposal) is replaced by restoration. • Waste is considered as a resource. • Design for repair (Murray et al., 2017). Build resilience • “Diversity is a key driver of versatility and resilience” Ellen through diversity MacArthur Foundation, 2015a, p. 7). • All possible solutions are employed to ensure sustainability. Rely on energy from • “The energy required to fuel the circular economy should be renewable sources renewable by nature, in order to decrease resource dependence and increase systems resilience (to oil shocks, for example)” ( Ellen MacArthur Foundation, 2015a, p. 8). • Main energy source for the CE. Think in systems • “Ability to understand how parts influence one another within a whole, and the relationship of the whole to the parts” (IMSA, 2013, p. 16). • The impact of parts in a whole. • Harmonious whole to parts relationship links from parts to whole. • Links and consequences of parts and whole are considered. • Core of CE (IMSA, 2013). • Interdependent systems. Think in cascades • Extraction of additional value from materials. • Cascading materials by other applications. • Use and re-use of products till they are fully utilised (Wijkman and Skånberg, 2015).

Source: Adapted from Ellen MacArthur Foundation (2013a; 2015a)

Furthermore, the CE may be portrayed as a win-win-win approach where producers, consumers, and the environment all benefit. Waste reduction, resource utilisation, and eco- efficiency are ways of creating resource value and, as such, serve as substrata for the CE.

Figure 3.3: Overview of the CE

68 3.2 Background of the Circular Economy Since the CE aims to design out waste, it does not depend only on waste prevention and reduction (Schulte, 2013) but inspires innovation through the entire value chain (European Commission, 2014a). This indicates that the CE relies on existing sustainability concepts (environmental, social, and economic) to achieve its overarching aim – SD. The sustainability concepts could be likened to pillars supporting members of a unit (Merrian-Webster Dictionary, 2016). The Ellen MacArthur Foundation (2013a) identified some of these pillars as regenerative design, biomimicry, cradle to cradle, industrial ecology, blue economy, and performance economy, and referred to them as the CE’s schools of thought, or roots (see Figure 3.4). Figure 3.5 shows the theoretical framework of the CE, where its principles, pillars, and theories are applied to achieve SD, while Table 3.4 compares them with the CE.

Figure 3.4: CE roots Source: Author (2018)

Figure 3.5: CE framework Source: Author (2018)

3.2.1 Comparison of the CE’s Roots Each sustainability concepts supports the CE in a unique way. They share some similarities, since their common aim is to achieve sustainability. Comparison of these concepts as shown in Table 3.4 is based on the characteristics categorised into six by Geisendorf and Pietrulla (2018). The first category is motivation(s) to achieve sustainability that focuses on the environment, and economic (profitability) and social concerns, while the second category describes waste management ideas including waste reduction, zero waste, and technological and biological substances (Ellen MacArthur Foundation, 2013a). Practical implications of the concepts form the crux of the third category. These include suggestions about what each concept provides, such as business models, operations, measurement tools, and policy. Based on the economic characteristics of the concepts, the fourth category focuses on the economic sectors where each concept is applicable. These include primary (raw material), secondary (manufacturing and industry), and tertiary (service) sectors. The fifth and sixth categories focus on the economic scope and life-cycle activities of the concepts. The former entails application of the concepts at the macro, meso, and micro (individual and company) levels (Su et al., 2013; Zhijun & Nailing, 2007), while the latter are activities during the lifecycle phases of a product, including development, raw material sourcing, production processes, use, user feedback, end of life (disposal), and transportation (Geisendorf & Pietrulla, 2018).

From Table 3.4, it can be seen that all concepts prioritise the environment and are motivated by the need to reduce environmental degradation. In addition, they all require efficiency and waste minimisation in their approaches to waste management. Likewise, all concepts are applicable in the secondary sector of the economy, including construction, manufacturing, and product assembly industries. Although the characteristics of these concepts vary, some have characteristics that are unique to the CE. For example, the cradle-to-cradle concept (C2C) shares similar aims and characteristics with the CE (Lieder & Rashid, 2016) and is closely related (Esposito, Tse, & Soufani, 2017), as evident in Table 3.4. However, the CE and the C2C differ in economic scope, with the former focusing on micro (company and product) and macro levels while the latter concentrates on micro and meso levels (Geng et al., 2012). As revealed by Geisendorf and Pietrulla (2018), regenerative design, C2C, biomimicry, and eco- effectiveness are compatible with the CE because they are product-design-based approaches, while the performance economy and natural capitalism are service-based approaches.

Industrial ecology aims to turn waste into a resource (which is one of the tenets of the CE), while reverse logistics and the blue economy are focused on profitability, with the former concentrating on the company or products while the latter exhibits few social and environmental characteristics. Of all the concepts, only biomimicry, regenerative design, resource efficiency, permaculture, and extended producer responsibility (EPR) are not performance indicators of the CE (Geisendorf & Pietrulla, 2018).

Table 3.4: Comparison of the CE roots

effectiveness - esponsibility

ource efficiency ource

Categories Characteristics Economy Circular Industrial ecology Cradle to Cradle Biomimicry design Regenerative Blue economy Performance economy & Eco efficiency Eco Res passports Material logistics Reverse emission Zero Permaculture capitalism Natural Extended producer r Motivation Environmental                Economic (Profitability)     Social          Waste Management Efficiency and waste reduction                Zero waste    Technological/biological substances     Practical implications Business model perspective         Focus on operations        Measurability           Policy      Economic sectors Primary sector (e.g. Mining)          covered Secondary sector (e.g. Construction)                Tertiary sector (e.g. Service)         Economic scope Macro-economic perspective      

effectiveness - esponsibility

ource efficiency ource

Categories Characteristics Economy Circular Industrial ecology Cradle to Cradle Biomimicry design Regenerative Blue economy Performance economy & Eco efficiency Eco Res passports Material logistics Reverse emission Zero Permaculture capitalism Natural Extended producer r Meso-economic perspective    Micro-economic perspective            (Company) Micro-economy perspective (Product)           Life cycle activities Product development          Raw material sourcing         Production processes            Use       Customer relationship management         End of life/Disposal             Transportation       Source: Adapted from Geisendorf and Pietrulla (2018)

The contribution of these concepts to the construction industry is summarised below:

• Closing the loop through reuse and recycling – Concepts including IE, C2C, regenerative design, eco efficiency, eco effectiveness, reverse logistics and zero emissions, when applied in the construction industry, can enhance closing the material loop through reuse and recycling. • Resource efficiency – C2C, IE, zero emissions, eco efficiency, eco effectiveness and natural capitalism can contribute to resource efficiency when waste is seen as a resource. • Design – Biomimicry can contribute to the construction industry while regenerative and eco effectiveness could contribute to achieving the principles of sustainability and eco design. • Service models – Performance economy and natural capitalism are two main concepts that emphasise the need to maximise the service of a product rather than owning it. • Environmental protection – All concepts, including the blue economy, permaculture, and EPR, emphasise the need to protect the environment by minimising pollution.

From the foregoing, the CE has the potential to facilitate SD across all sectors. Therefore, there is a need for industries/businesses to adopt the CE concept for production (design and manufacturing), distribution, and consumption.

3.3 Transition to the Circular Economy Transitioning to the CE entails radical changes, especially in production and consumption, which suggests new and significant roles for all stakeholders (Mendoza et al., 2017; Bocken, de Pauw, Bakker, & van der Grinten, 2016). For instance, producers or manufacturers would become service providers (Esposito, Tse, & Soufani, 2016), while consumers would rent a product rather than own it. For producers, a shift from business-as-usual thinking to CE- oriented sustainable business models is encouraged (Bocken, Short, Rana, & Evans, 2014; Boons & Lüdeke-Freund 2013; Schaltegger et al. 2012) to ensure a smooth transition to the CE. Therefore, producers would need to conduct business differently by combining various business models, design methods, strategies, tools, and approaches (Bocken et al., 2016). To transition to the CE, product design, business models, reverse networks, and enabling conditions (described in subsequent subsections) are essential and referred to as building blocks (Arcadis, 2017). These have received wide attention in the literature, especially in circular

product design (Bakker et al., 2014) and in circular business models (Bocken et al., 2016) due to their potential to minimise material waste.

3.3.1 Product Design Product design is an important factor for organisations. Through material selection, efficient production can be achieved by incorporating modular components, standard sizes, and design for disassembly (Arcadis, 2017). This will not only ensure efficient production, but it will create products that are durable (Bakker et al., 2013), cost effective, and sustainable. For example, McDonough and Braungart (2013) suggest that intelligent product design will result in material and energy efficiency. Ramani et al. (2010) have emphasised the importance of the design stage in product development. In support of Ramini and colleagues, the European Commission (2012) claims that about 80% of the environmental impacts of a product are determined at the design stage. In addition, Lieder and Rashid (2016) have revealed that in the design of sustainable circular systems, product design is strategic, especially for critical materials. According to Ashby (2012, p. 39) critical materials are those materials whose “supply is concentrated in one country or could be restricted by [a] few corporate interests, and because they are used in products that are important economically or for national security”. This suggests that the design of any product is a vital determinant of the extent of its use, performance, and value.

Some authors have proposed product design strategies and frameworks. For instance, Allwood, Ashby, Gutowski, and Worrell (2011) proposed design strategies with an overarching aim of material efficiency, where products are designed with fewer types of materials and components are reused or remanufactured. Likewise, a product design framework emphasising eco-design elements through design for disassembly was proposed by Van den Berg and Bakker (2015) and Poppelaars (2014) for the CE. In support of design strategies, Desai and Mital (2003) claim that about 90% of disassembly potential is determined when products are optimised at the design phase, further stressing the importance of design for material recovery, product repair- ability, and recyclability (Prendeville, Sanders, Sherry, & Costa, 2014; Mulder, 2012). Design for disassembly through modular design embraces design for adaptability, allows for technological upgrades, and increases a product’s lifespan (Geldermans & Rosen-Jacobsen, 2015). This is what Chertow (2000, p. 331) referred to as “eliminating waste at the front end of the process.” Likewise, Esposito et al. (2018) perceived that when products are designed for disassembly, waste will be eliminated. It is evident that product design would not only benefit the environment and consumers but producers or manufacturers as well. Therefore, Ying and

Li-jun (2012) provide some design recommendations for product design enterprises. These are:

• Selection of green materials due to their low energy consumption, environmental friendliness, ease of recycling, optimal reuse, and high resource utilisation. • Consideration of environmental and resource consumption during design of the whole lifecycle of products.

Based on the benefits of product design, including material circularity and resource reduction, the European Environmental Bureau (EEB) (European Environmental Bureau, 2015) and the European Commission (EC) (European Commission 2015; 2014a; 2014b) stressed its importance in the development of the CE. Also, Geisendorf and Pietrulla (2018) noted that material and resource circularity can be achieved through circular design incorporated throughout the lifecycle of products and materials. Therefore, Lieder and Rashid (2016) have suggested that designers should be conscious of the CE by designing products with manifold usage phases. In contrast, Hatcher, Ijomah, and Windmill (2011) observed that no design is capable of considering the whole lifecycle of a product due to lack of information to guide design decisions and appropriate design tools. Circular product design is just gaining traction, and little research has been conducted on its application to the construction industry (Kane, Bakker, & Balkenende, 2018). This application and its effects on waste minimisation is considered and described in section 3.7.

3.3.2 Business Models of the Circular Economy Accenture (2015, p. 1) described the CE as a system “where growth is decoupled from the use of scarce resources through disruptive technology and business models based on longevity, renewability, reuse, repair, upgrade, refurbishment, capacity sharing and dematerialization”. Several authors have reported that the linear economy is no longer viable. According to Bakker and Hollander (2013), the linear economy is based on ‘sell more, sell faster’ principles that are not suitable for durable products and services. Likewise, Gerholdt (2015) claimed that the CE focuses on materials flow management, relying on product design, business model innovation, reverse logistics and cross-sector collaboration. She further described the CE as a regenerative model that addresses environmental degradation, brings about innovation and competitiveness, drives performance and kindles economic growth and development through viable business opportunities. Bakker and Hollander (2013) observe that the overall success of the CE hinges on new business models being capable of capitalising on products’ longevity.

Several definitions of business models exist but this study adopts the definition provided by Osterwalder and Pigneur (2010, p. 6) which states it as “the rationale of how an organisation creates, delivers and captures value”. As suggested by the Ellen MacArthur Foundation (2013a), new business models are required for a shift to the CE, especially the socio and technological aspects (Geissdoerfer, Savaget, Bocken, & Hultink, 2017). Business models are closely related to circular design, but aim to create value (Circle Economy, 2012) and value capture for products (Clauss, 2017). Ernst and Young Accountants (2015) envisaged that in a CE, a radical change in relationship between customers and products and services is possible. Lacy, Rosenberg, Drewell, and Rutqvist (2013) suggest that product vendors should think of product resources rather than inputs, and customers as users and not buyers. The Ellen MacArthur Foundation (2013a) recognised five business models (Accenture, 2015; Bakker and Hollander, 2013; Rabobank Industry, 2015; Hieminga, 2015), which are:

• Circular input model: this is a circular supply business model designed to create materials and resources that phase out scarce resources and replace them with biodegradable, renewable resources (Ernst & Young, 2015; Gerholdt, 2015; Lacy et al., 2013). While this model ensures durable products in combination with short life consumables, revenues are generated through repeat sales of consumables (Bakker & Hollander, 2013). • Waste value model: this involves recycling and upcycling (creating a product of higher quality) with technological innovations and capabilities aimed at recovering the embedded value of waste and reusing resource output by making it into other products and then delivering these into markets to maximise their economic value (Ernst & Young, 2015; Gerholdt, 2015; Lacy et al., 2013). A unit sale of service or product is the primary source of revenue for this model (Bakker & Hollander, 2013). • Lifespan model: this aims to extend a product’s lifecycle in order to improve its value by repairing, upgrading, and remanufacturing to render it economically beneficial (Ernst & Young, 2015; Gerholdt, 2015). According to Lacy et al. (2013), a product’s materials often possess a high embedded energy component that makes them more valuable in energy terms than the products. Similarly, Bakker and Hollander (2013) observe that this model is built on a high grade product with a long life, while the source of revenue is through the sale of durable products. • Platform model: this model encourages the efficient use of products and services through sharing of non-usable goods (Ernst and Young Accountants, 2015). Lacy et al. (2013) described this model as collaborative consumption of products. Examples are Uber and

Airbnb (Lacy et al., 2013). This model maximises the value of products and services (Gerholdt, 2015). In addition, the primary source of revenue for this model is based on the delivery of a desired result (Bakker & Hollander, 2013). • Product as service model: here, products are made available to one or more customers on a lease contract or rental fee as against conventional ownership of products (Ernst & Young, 2015; Gerholdt, 2015). Producers, therefore, see themselves as service providers and they continue to own their products. The advantages of this model include: product longevity, closer customer relationships, and reusability (Ernst & Young, 2015; Lacy et al., 2013). This model, however, requires high levels of maintenance from the service providers (Gerholdt, 2015). According to Bakker and Hollander (2013), revenue for this model is generated through increased product access.

A circular business model is different from a traditional model, as it focuses on value creation from all sectors, including resources or materials and stakeholders, while ensuring societal and environmental benefits (Antikainen & Valkokari, 2016). Therefore, to create a regenerative business model, Lacy and Rutqvist (2015) identified resource constraints, technological developments, and socioeconomic opportunities as key drivers and proposed five new business models, which are:

• Circular Supply Chain: encourages producers to use renewable or natural sources of energy, maximise use of materials and ensure closed-loop processes to increase product predictability and control while reducing cost (Lacy & Rutqvist, 2015). Design is central to achieving a circular supply chain and designers are to consider all factors that guarantee reuse of by-products and waste. To achieve this, the circular supply chain model relies on cradle-to-cradle, biomimicry, and design for disassembly. • Recovery and Recycling: the way waste products and materials are viewed has the potential to change the way waste is defined (Svensson, 2015). The recovery and recycling model is focused on material recovery, upcycling, and recycling to maximise value in products (Ovaska, Poutiainen, Sorasahi, Aho, Levanen, & Annala, 2016) and according to Accenture (2015), companies producing large volumes of waste or by- products would benefit greatly from this model as it could lead to new ways of turning waste to wealth. Therefore, products should be designed to ease the conversion process. For instance, products designed to be disassembled at the end of their lives would facilitate sorting and segregation and, in the long run, companies would benefit from reduced costs of waste management, including disposal, increased revenue, diminished

environmental impacts, convenient disposal options for customers, improved interactions between companies, and between customer and companies, and insights into product disposal (Lacy & Rutqvist, 2015). Aside from product design, efficient use of resources in production processes could contribute to material and energy efficiency (UNEP & Sida, 2006) and replacement of non-durable materials (Nilsson, 2007). • Building products to last: also known as the Product Life-Extension Business Model (Esposito, Tse, & Soufani, 2018), this model ensures products are highly durable to avoid frequent replacements. The purpose of this model is to ensure products have extended useful lives through continuous use and reuse. If manufacturers maximise the value of available resources by producing durable products, the frequency with which replacements are required would be reduced (Lacy & Rutqvist, 2015). As a result, the design of products, where factors such as standardisation, durability, and efficiency are considered, is central to extending a product’s life (Bocken et al., 2016). • Sharing platform: also known as ‘collaborative consumption’ or the ‘sharing economy’. This centres on the idea that individual ownership of products or goods is substituted by “schemes of sharing, bartering, lending, trading, renting and gifting” (Botsman & Rogers 2010, p. xv). As a socio-economic concept, sharing platforms encourage the exchange of physical and intellectual resources (Matofska, 2016) while creating social interactions between users (Crowther & Gilman, 2014). According to Crowther and Gilman (2014), there are environmental, economic, and social benefits attached to sharing platforms, including resilient use of financial resources, sustainable use of resources, and social connections. The sharing economy is not new – its novelty is in the application of digital technology, where products and goods are shared via the internet (Lacy & Rutqvist, 2015). For instance, Spotify, Google Play, Dropbox, One Drive, and Ebay are all sharing platforms available via the internet. On the other hand, sharing platforms for physical assets are becoming increasingly popular around the world and are capable of reducing environmental footprints. Examples include: Uber, Airbnb, and OFO (bike sharing service). The majority of these services are business- to-consumer (B2C) while the business-to-business (B2B) market is yet to be fully explored (Stott, Stone, & Fae, 2016). Since the aim of sharing models is to ensure efficient use of materials, it can be applied in the CE (Naustdalslid, 2014; Ellen MacArthur Foundation, 2013b). For instance, technologies and infrastructure may be shared among businesses (Balanay & Halog, 2016).

• Product-as-a-Service (PaaS): “refers to the concept of offering the product as a service which challenges the traditional business approach of selling tangible products” (Rizos, Tuokko & Behrens, 2017, p. 14). Similarly, Bocken et al. (2016) described PaaS as a model that discourages the physical ownership of products by providing services or performance of such products to consumers. Lacy & Rutqvist (2016) also further emphasised that customers buy services or performance of a product in PaaS models, rather than the product itself. This results in a system that is resource efficient (Stahel, 2010). Therefore, the focus is a shift from the conventional ownership of products to service-based products (Accenture, 2015) where the liability for products is shifted to manufacturers or providers. The PaaS model can be implemented in different ways, including pay-per-use, leasing, rental, and performance agreements (Rizos et al., 2017). The social characteristics of PaaS creates a form of relationship between consumers and producers and provide feedback, especially on areas where services could be improved. The economic advantage of PaaS is a win-win situation for consumers and producers. Producers make profits from continuous revenue obtained from services offered, while consumers only pay for services when needed. To achieve socio- economic benefits, companies have to devise means of delivering product services that represent value for money while retaining the ownership of the product. This can be achieved by maintaining and improving product value, performance, and quality (Gregson, Crang, Fuller, & Holmes, 2015). Several authors (Geisendorf & Pietrulla, 2018; Pialot, Millet, & Bisiaux, 2017; Pagoropoulos, Pigosso, & McAloone, 2017; Johansson et al., 2016; Bocken et al., 2016; Vasantha, Roy, & Corney, 2016) have identified PaaS as an important model in achieving sustainable business models.

From the foregoing, it is obvious that these business models represent a company’s approaches to minimise waste, extend product lifespan, create value through shared use, and encourage use of renewable sources while closing resource loops. These business models also form part of the Circular Economy Business Models (CE-BMs) development framework, which is described in the next section.

3.3.2.1 Framework for Circular Business Models The Ellen MacArthur Foundation (2015a, 2015b, 2015c) has identified a model comprising six themes in a framework known as ReSOLVE. The ReSOLVE framework (Regenerate, Share, Optimise, Loop, Virtualise, and Exchange), as described in Table 3.5, has been recognised and

replicated as a tool for developing CE-BMs and transitioning to the CE (Ellen MacArthur Foundation, 2015a; Arup, 2016) and is applicable in the construction industry.

Table 3.5: ReSOLVE Framework

Abbreviation Framework Characteristics RE Regenerate • Shift to renewable energy and materials • Reclaim, retain, and restore health of ecosystems • Return recovered biological nutrients to the biosphere S Share • Share assets (e.g. cars, bike, rooms, appliances etc.) • Reuse/second-hand (e.g. clothing, phones, etc.) • Prolong life through maintenance, design for durability, upgradability, refurbishment etc. O Optimise • Increase performance/efficiency of products • Remove waste in production and supply chain • Leverage big data, automation, remote sensing and steering L Loop • Remanufacture products or components • Digest anaerobically • Recycle materials • Extract biochemicals from organic waste V Virtualise • Dematerialise directly (e.g. books, DVDs, CDs, travel etc.) • Dematerialise indirectly (e.g. online shopping) E Exchange • Replace old with advanced non-renewable materials • Apply new technologies (e.g. 3D printing) • Choose new product/service (e.g. multimodal transport) Source: Adapted from Ellen MacArthur Foundation (2015a, 2015b, & 2015c).

Similar to the ReSOLVE framework, Bocken et al. (2016) identified resource cycles as a circular business model.

3.3.3 Enabling Conditions For ease of transition to the CE, some enabling conditions are required. According to Arcadis (2017), some of the conditions include:

• Consumer awareness and education • Eco clustering of businesses or organisations (i.e. group of businesses that are working together to minimise their impacts on the environment despite being in different locations (Dimitrova, Lagioia, & Gallucci, 2007) • Infrastructure such as recycling facilities • Legislation including laws and regulations • Risk management 81

• Financial capabilities

These conditions contribute to the CE, and thereby to SD. For instance, by enhancing consumers’ awareness and education about the need to reuse and recycle materials, the CE can significantly contribute to resource efficiency and waste minimisation. Likewise, if regulatory policies are formulated, the CE can be incorporated into different sectors of the economy.

3.3.4 Reverse Networks Reverse networks deal with the return of products or goods by users and collection by manufacturers. For this to work, manufacturers need to take responsibility for their products and deploy networks for collecting them at the end of their useful lives. Such methods may incorporate incentives (Lewandowski, 2016) or return acceptance obligations (Arcadis, 2017). Likewise, reverse logistics is another example of reverse networks. Some specific skills, including “delivery chain logistics, sorting, warehousing, risk management, power generation and even molecular biology and polymer chemistry” are essential for reverse networks to ensure circularity of materials, as suggested by the Ellen MacArthur Foundation (2013b, p. 75). The foundation has revealed that a decrease in material leakage out of the system is possible by establishing “cost-effective, better-quality collection and treatment systems, and effective segmentation of end-of-life products” (p. 75).

3.3.5 Top-down and Bottom-up Approaches To realise the concept of a CE, an all-inclusive framework combining both top-down and bottom-up approaches, supported by appropriate stakeholders, is required (Lieder & Rashid, 2016). An example of a top-down approach is backcasting, described as “an approach to futures which involve(s) the development of normative scenarios aimed at exploring the feasibility and implications of achieving certain desired end points” (Robinson 2003, p. 841). For companies, backcasting is aimed at changing current practices to more ambitious ones (Broman & Robert, 2015) through strategies and business ideas, while for governments it is aimed at achieving specific targets or goals through policies that provide practical steps for meeting targets. An example is the European Union CE programs (European Commission 2015; WRAP, 2013). On the other hand, the application of backcasting is evident in a variety of industries and sectors, such as the business sector (Broman & Robert, 2015; O’Hare, 2010), agricultural and forestry (Quist & Vergragt, 2001), tourism (Benckendorff et al. 2009), transport (JRC, 2008), energy (Thollander et al. 2013; Giurco et al. 2011; Pokharel 2010;

Anderson et al. 2008), and the built environment (Quist & Vergragt 2006; Green & Vergragt 2002; Quist et al. 2001).

As for bottom-up approaches, a relevant example is eco-design, which aims at minimising waste and environmental footprints through product design that reduces resource consumption and maximises use throughout a product’s lifecycle (Lifset & Graedel 2002). Unlike the top- down approach, the bottom-up approach is adopted at the enterprise or firm level, where product design concepts and service performance are conceived and realised respectively.

3.3.6 Tools and Techniques Life cycle assessment (LCA) is a technique for measuring the environmental impacts of a product throughout its lifetime, including resource consumption, waste generation, and energy use (Muralikrishna & Manickam, 2017; McIntosh & Pontius, 2016). According to ISO 14040, the LCA of a product is conducted in four stages, which are goal and scope, inventory analysis, impact assessment, and interpretation. The results of the assessment inform decisions about material choices, policy directions, product design, and marketing (Muralikrishna & Manickam, 2017). Therefore, manufacturers or organisations are encouraged to take full responsibility for the environmental impacts of their products, while consumers depend on a product’s LCA when they make purchases (McIntosh & Pontius, 2016). This approach would inspire sustainable production and consumption, which aligns with the business models of the CE. Several studies have been conducted on the application of LCA in the CE and SD. For instance, LCA was adopted for a sustainable supply chain management and CE study conducted by Genovese, Acquaye, Figueroa, and Koh (2017), and was found appropriate for calculating resource emissions and waste recovered. Scheepens, Vogtländer, and Brezet (2016) confirmed that LCA is suitable for measuring circularity in a CE system, while Hellweg and Canals (2014) considered it appropriate for studying material waste generation in a CE. This suggests that LCA can contribute to improving product design, and reduce waste, energy, and resource consumption. Having acknowledged its importance, Schepelmann (2009) identified some limitations, including lack of consideration for rebound and other social effects, consideration for potential environmental impacts only, and incomprehensiveness. In addition, Braungart, McDonough, and Bollinger (2007) argued that LCA approaches are intrinsically linear and not circular as claimed. However, its benefits outweigh the limitations and it has been considered the environmental assessment method most used (Ghisellini, Ripa, & Ulgiati, 2018).

Material flow analysis (MFA) is an analytical tool that evaluates the input and output of materials in a production system (Pomponi & Moncaster, 2017). MFA is “a systematic assessment of the flows and stocks of materials within a system defined in space and time” (Brunner & Rechberger, 2004, p.3). According to Gregory (2006), MFA is applied in environmental management and engineering, industrial ecology, resource and waste management, and human metabolism, which are building blocks for the CE. Furthermore, Gregory (2006, slide 7) revealed MFA’s five key goals, which are:

• “Delineate system of material flows and stocks”. • “Reduce system complexity while maintaining basis for decision-making”. • “Assess relevant flows and stocks quantitatively, checking mass balance, sensitivities, and uncertainties”. • “Present system results in [a] reproducible, understandable, transparent fashion”. • “Use results as a basis for managing resources, the environment, and wastes”.

It is evident from these objectives that MFA is a significant tool in sustainable material management as it assists in achieving sustainability, which is the main goal of the CE. Analysis of environmental, economic, and social issues is possible with MFA, as asserted by Fischer- Kowalski and Hüttler (1998). Some studies have identified relationships between MFA and the CE, while others have used MFA to explore the CE. For instance, Wen and Li (2010) explored methods of stimulating the CE using MFA while Allwood et al. (2012) examined flows of emissions, materials, and energy around the world through MFA. In addition, Wen and Meng (2015) used MFA to assess how the CE can be achieved through industrial symbiosis, while Chen (2009) endorsed MFA as a vital tool for understanding the economic dimensions of the CE. Overall, Brunner and Rechberger (2004) observed that MFA contributes to product design to make recycling easy.

3.4 Practical Applications and Implementation of the CE 3.4.1 Implementation The implementation of the CE depends on the drivers (section 3.5.2) and challenges (section 3.5.3) it confronts, as well as the benefits it provides (section 3.5.1). As previously stated (in section 3.3), all stakeholders at all levels need to support the transition and implementation of the CE. It is a “collective consciousness behaviour by a whole society whose culture varies one by one” (Ji, Zhang, & Hao, 2012, p. 726). Several authors (see section 3.5.3) have identified government’s role as being among the challenges in the transition and implementation of the

CE. The CE concept has been implemented in China, while similar concepts or strategies have been implemented in other countries (Japan, Germany, Netherlands, Austria, USA and UK) (Heck, 2006). The CE involves processes and cannot be copied mechanically in every country (Ji et al., 2012). However, a study of the implementation process and concepts/strategies adopted in these countries could serve as a guide for other countries.

3.4.2 Policies, Models and Strategies 3.4.2.1 Policies The role of policies in the implementation of the CE cannot be over-emphasised, having been advocated for and referred to as fundamental (Huamao & Fengqi, 2007). Several authors (Wu, Shi, Xia, & Zhu, 2014; Geng & Cote, 2004; Lowe, 2001) have revealed that a CE can be achieved if appropriate policies are formulated and implemented. Ren (2007) identified two categories of policies for promoting the CE, which are core and enabling policies (see Figure 3.6). The former is directly related to the CE, while the latter provides a platform for the CE to thrive. For instance, the proposed CE roadmap of the European Commission can be seen as an enabling policy, since it is aimed at addressing some of the barriers and challenges hindering the development of the CE (European Commission, 2015). Policies may be worded in different ways, including policy instruments, top-down approaches, and bottom-up approaches (Winans, Kendall, & Deng, 2017). However, their objectives and directions may vary depending on the specific needs to be addressed. For instance, a CE policy may focus on waste minimisation, as suggested by Ren (2007) and Geng et al. (2010). Similarly, it may provide directions on product use and recycling while encouraging industry participation (Leslie et al., 2016). In addition, CE policies may stimulate symbiotic relationships among stakeholders to proffer lasting solutions to CE-related challenges (Boix, Montastruc, Azzaro-Pantel, & Domenech, 2015; Mattiussi, Rosano, & Simeoni, 2014).

Policy Core • Cleaner Production • Eco-Industrial CE Parks Policy • Instruments • Waste Recycling • Top-down • E.g. CE Road Bottom-up Enabling map (EC 2015)

Figure 3.6 : CE policies Source: Adapted from Ren (2007)

Several CE policies have been proposed by organisations, governments, and policymakers. Some have been approved and are yielding results, some are under discussion, whereas others are at the proposal stage. For example, in China, the Dalian municipal government in 2004 established a CE-related regulation that provides guidelines on the use of energy-saving design and solar heating systems and around the same time completed several demonstration green buildings, which are now being considered throughout the municipality and the entire country (Dalian Municipality, 2004; 2007). Other practical policy approaches include tax, laws, economic incentives, and eco designs (Kalmykova, Sadagopan, & Rosado, 2018; Adams, 2016). These have proven to be effective in the places where they have been applied. For instance, Ghisellini et al. (2016) claimed that the use of landfill tax, bans, and regulations contributed to the low landfill rate of 3% in the Netherlands, while Adams (2016) argued that tax breaks could give rise to the use of recycled materials in building construction. It is evident that CE-related policies have been introduced by some governments. Some of these policies may not address the specific objectives and challenges of the organisations because they may be broad (Van Ewijk & Stegemann, 2016). Therefore, there is a need for organisations to introduce CE-related policies that are specific to their activities (Korhonen, Nuur, Feldmann, & Birkie, 2018).

3.4.2.2 Cleaner Production Cleaner production aims to increase economic benefits and minimise the negative environmental impacts of production processes through precautionary strategies (UNIDO, 2014; Li, Bao, Xiu, Zhang & Xu, 2010; Brown & Stone, 2007; Yap, 2005). It has been considered as a strategy for maximising resource use while preventing waste generation during production stages (Su et al., 2013). According to Ghisellini et al. (2016), cleaner production reduces waste and cost of disposal. In support of Ghisellini et al.’s. (2016) claim, Yap (2005) indicated that through resource efficiency, cleaner production would improve an organisation’s economic benefits by decreasing the cost of waste treatment and disposal. In addition, Brown and Stone (2007) observed a shift in perception of the relationship between business and the environmental effects of products and services prompted by the introduction of cleaner production.

Due to the aforementioned benefits of cleaner production, it has been promoted and adopted in China through the promulgation of the Cleaner Production Promotion Law (one of various policies introduced to counter environmental pollution in 2002) (Yap, 2005; Geng et al., 2010; 2012; Su et al., 2013). Several authors (Zhang et al. 2012; Geng et al., 2010; Bonilla, Almeida,

Giannetti, & Huisingh, 2010; Schnitzer & Ulgiati, 2007) have attributed the success of cleaner production, in terms of its effectiveness and efficiency, to the institutional frameworks available, and decision makers’ capability and foresight in encouraging sustainable ways to use resources through appropriate policies. For instance, heavily polluting companies need to reduce their energy and carbon footprints (Hicks & Dietmar, 2007) as mandated by government legislation. Similarly, financial incentives are provided by governments to companies to encourage the adoption of cleaner production (Shi et al., 2006). For companies, cleaner production is practiced through toxic use reduction, pollution prevention and Design for Environment, which are interrelated (Yap, 2005; Van Berkel, Willems, & Lafleur, 1997). In the construction industry, cleaner production is practiced at the design stage via waste prevention designs such as design for environment, design for material reuse or recycling, and design for disassembly to minimise waste sent to landfill (Esa et al., 2017). This suggests that cleaner production is vital in the design of products and services and may be extended to other aspects of construction such as contract, project, and value management. Shi et al. (2006) revealed that cleaner production is essential for controlling pollution. It has also been considered as a significant strategy for implementing the CE concept and SD (Bilitewski, 2012; Li, Bao, Xiu, Zhang & Xu, 2010; Van Berkel, 2000).

3.4.2.3 Eco Design Eco design has been described as an important tool that is commonly used to incorporate environmental considerations into products, especially at the design phase (Su et al., 2013; CIRAIG, 2015). Simply put, “eco design focuses on the integration of environmental considerations into product development” (Karlsson & Luttropp, 2006 in Bovea & Pérez‐Belis, 2012, p. 61). It partners with LCA and sometimes relates to design for environment to reduce environmental impacts throughout the lifecycle of a product (CIRAIG, 2015). Eco design’s central focus is on product design and it has been used interchangeably with design for environment. It has the capacity to improve the eco efficiency of companies (Aoe, 2007) and has been adopted by some enterprises as part of their cleaner production strategies and in some cases as a policy. For instance, the EU adopted eco design directives that provide basic design requirements for energy-based products to optimise their energy performance (European Commission, 2012).

CIRAIG (2015, p. 19) suggested implementing eco design as “an analytical thought process” at the product design stage and not as a “specific method”. It should consider appropriate design and engineering practices when incorporated throughout a product’s lifecycle to achieve the

desired results. Since 80% of environmental impacts may be reduced in the design stage, eco design should be seen as a means to achieve eco-efficiency (Knight & Jenkins, 2009). Therefore, it should be considered to develop a sustainable competitive edge in product design. Eco design tools have been categorised as quantitative, qualitative, and semi-qualitative (Ernzer & Wimmer, 2002; Bovea & Pérez‐Belis, 2012). Likewise, Knight and Jenkins (2009) categorised eco design tools into guidelines, checklists, and analytical tools (see Figure 3.7). These tools encourage heavily polluting manufacturing or processing companies to adopt sustainable and efficient methods for production (Negny, Belaud, Robles, Reyes, & Ferrer, 2012).

Eco Design

Guidelines Checklists Analytical tools

• Broad scope • Specific and detailed • Detailed and systematic • Largely applicable • Narrow analysis • Includes whole life • Selected stages of • Specific stages of

cycle lifecycle lifecycle • Black/grey/white • Eco-indicators, impact checklists assessment, LCA, LCC etc.

Figure 3.7: Eco design categories Source: Adapted from Knight and Jenkins (2009)

With eco design, the interplay between consumers’ needs, production costs, policies, designs, and businesses (Luttropp & Lagerstedt, 2006) may be challenging for companies. As a result, Knight and Jenkins (2009, p. 61) argue that eco design should not be mistaken for sustainable design, as the former “does not incorporate social and ethical aspects” of sustainability. Due to its environmental characteristics, including resource efficiency, reuse, and recycling, it may be considered vital to the CE concept (Zhu, Geng, & Lai, 2010). Likewise, it has the potential to advance the CE model by efficient material and resource use (Prendeville et al., 2014; Sherwin & Evans, 2000).

3.5 Assessment of the CE 3.5.1 Benefits of the Circular Economy The benefits of the CE include social, economic, and environmental advantages and various authors argue that it is a sustainable approach. Geng et al. (2012), have identified its potential social benefits, including improved relationships between local societies and industrial sectors, improved public awareness of environmental issues and health benefits, as well as employment opportunities from recycling businesses. Andrews (2015) has emphasised that the CE creates employment opportunities for design graduates and professionals with related expertise across all industries. He notes that the CE has the potential to reduce unethical practices and corruption in the industry. It is expected to facilitate the selection of ethical suppliers while encouraging others to change (Andrews, 2015). Yuan et al. (2006) has added that it could reform environmental management and create opportunities for collaboration between consumers and producers that will prolong commercial relationships between them. Similarly, Moreno et al. (2015) have supported the claim of Yuan et al. (2006), adding societal benefits to the list of benefits. With the CE, national security will be strengthened owing to increased sustainable energy supplies (Su et al., 2013). Zhijun and Nailing (2007) acknowledge the potential social impacts of the CE to integrate populations, close income gaps, promote social justice and prevent environmental poverty.

According to Ghisellini et al. (2016), Persson (2015), Jun and Xiang (2011), and Zhu et al. (2010), the CE aims to achieve economic growth with fewer resources. It is expected to improve resource productivity, reduce materials cost (Yuan et al., 2006, Moreno et al., 2015), increase revenue from sales of waste (Geng et al., 2012) and allay the demand-driven price volatility of raw materials and supply risks (Crowther & Gilman, 2014). Preston (2012) has asserted that the CE could assist in the industrialisation of developing countries and reduce the vulnerability to resource price shocks in developed countries. Ren (2007, p. 128), however, observed the CE from an economic perspective and concluded that, “it is able to internalise the environment as an endogenic factor in the promotion of economic development”. Moreno et al. (2015) identified the CE as having the potential to make additional profit and create new business models in any industry. Benton, Hazell, and Hill (2014) also posited that the CE is liable to provide businesses with direct cost savings, reduce risk, and provide reputational benefits. Therefore, without placing undue pressure on resources, it could be a market differentiator.

According to Geng et al. (2012, p. 221), the potential environmental benefits of the CE are numerous, and include: “conservation of natural resources (especially non-renewable resources such as water, fossil, fuels and minerals), reduced environment impacts through efficient energy and material and less water discharge, avoidance of toxic materials, extended life cycle of landfill sites, and recovery of local ecosystem”. Andersen (2007) noted that the CE will result in positive environmental outcomes through efficient waste minimisation, resource minimisation, and adoption of cleaner technologies. Similarly, Jun and Xiang (2011) revealed that the CE is expected to conserve resources and provide adequate environmental protection, while Ghisellini et al. (2016) claim that the objective of the CE was to split environmental pressure from a thriving economy. The CE is expected to improve eco-efficiency (Yuan et al., 2006), mitigate environmental pollution, reduce waste and emissions (Wang, 2009), and prevent environmental poverty (Zhijun & Nailing, 2007). Ren’s (2007) ecological perspective of the CE reveals a balanced state where material flow between the socioeconomic system and ecosystem are restructured. The CE model is expected to reduce unsustainable pressure on natural resources, which will reduce environmental challenges (Preston, 2012; Zhu et al., 2010).

3.5.2 Drivers of the CE The successful transition to the CE needs to be driven by the stakeholders identified in Table 3.6. Several authors and organisations have identified the potential drivers of the CE. Bastein, Roelofs, Rietveld, and Hoogendoorn (2013, p. 62) identified some drivers that are important for the success of the CE in the Netherlands. They are categorised into four types: “education (developing and disseminating knowledge), business (entrepreneurial activities, market mechanisms and mobilising resources), policy and rules and regulations (government-related framework activities) and lobbying and framework activities (non-government-related)”. In the same way, Preston (2012) acknowledged several drivers, including standardisation, smart regulation, best practice and knowledge sharing, public awareness, and setting credible bench marks. He also recognised certification of CE products, which he described as an important factor in raising awareness among consumers and producers. Geng et al. (2012) suggest that investment in CE research and development will drive its acceptance and implementation. They emphasise the role of businesses in promoting the CE. The role of society in the adoption of the CE has also been described as highly important (Lehtoranta, Nissinen, Mattila, & Melanen, 2011). Moreno et al. (2015, p. 7) and Govindan and Hasanagic (2018) identified several drivers of the CE, categorised as: policy and economy, health, environmental protection, society, and

90 product development. As shown in Table 3.6, these categories were further classified into internal and external drivers, while corresponding stakeholders were identified.

Table 3.6: Drivers of CE

Category Drivers Classification Stakeholder Policy and Waste management laws and policies External Organisation economy & suppliers Economic growth through the Internal General implementation of a CE for sustainable consumption Profitability impacts Internal General Reduce waste disposal cost Internal General Future price and uncertainty cost for External Organisation materials and policy & supplier Health Public health vulnerable to External Society overconsumption of resources and energy Animal health vulnerable to excessive External Society resources and energy consumption Environmental Because of climate change/global warming, External Government protection the implementation of CE in sustainable consumption is important Modern agriculture increases productivity External Society rapidly, but pays a huge price for excessive consumption of resources and energy Renewable energy demand is increasing External Government and environmental protection is therefore important Future price and cost uncertainty for energy External Organisation & supplier Society The implementation of a CE is important to External Government protect future population growth Rapid urbanisation has adversely affected External Government the environment Potential job creation within the supply Internal Organisation chain & supplier The environmental awareness of consumers External Consumer puts pressure on companies to create a CE in sustainable consumption User demand attitudes External Consumer Product Improve material and energy consumption Internal Organisation development in the supply chain & supplier Increase product value by enhancing Internal Organisation quality Industry pressure points (material scarcity) External Organisation Industry pressure points (disruption of External Organisation material flows) Source: Adapted from Govindan and Hasanagic (2018) and Moreno et al. (2015, p.7)

In China, changes in governance philosophies and onerous economic conditions (which led to expensive resources and environmental degradation) have been acknowledged as drivers of the CE (Liu et al., 2009). Similarly, Ren (2007) recognised the struggle between economic growth, heavy pollution, and scarcity of resources as drivers of the CE in China. He also identified environmental issues, climate change and challenges relating to renewable energy as motivators of the CE in Japan and Germany. According to a report by the UK Chartered Institute of Waste Management (2014, p. 6), “the main drivers for CE are increasing price volatility and supply restrictions on virgin resources, policy drivers such as producer responsibility regulations and a changing consumer culture”. Similarly, Crowther and Gilman (2014) acknowledge spiralling prices and unparalleled volatility as motivators of the CE. Giurco, Littleboy, Boyle, Fyfe, & White (2014) identified the following problems and described them as motivators of the CE. They include increased generation of waste materials, rising costs of waste disposal, and demand for sustainable practices that reduce greenhouse gas emissions and energy consumption.

Although the CE has yet to be adopted in Nigeria, several strategic approaches could serve as drivers of the CE there. According to the Country Report at the Rio+20 Summit tagged “Nigeria’s Path to Sustainable Development through Green Economy” (Federal Government of Nigeria, 2012, p. ixx), the following mechanisms were identified to operationalise SD:

• “Governance” • “Education, public awareness and capacity building” • “Stakeholders’ participation” • “Information and Communication Technology (ICT)” • “Environmental Monitoring and Data Management” • “Science, Technology and Innovation” • “Research for development” • “Financing for sustainability” • “International and Regional collaboration”

In addition to these mechanisms, some economic and social programmes have been developed by the government to achieve SD. These are shown in Table 3.7.

Table 3.7: Economic, Social and Environmental Programmes in Nigeria

S/N Economic, Social, and Environmental Source Programmes 1. One Local Government One Product (OLOP) Small and Medium Enterprises Development Agency (SMEDAN) Act (2003) 2. National Poverty Eradication Programme (NAPEP) Federal Republic of Nigeria 3. Nigerian Extractive Industries Transparency Initiative NEITI Act (2007) (NEITI) 4. Standards Organisation of Nigeria (SON) Laws of Federal Republic of Nigeria, 1971, Cap 412 5. Consumer Protection Council (CPC) Laws of the Federal Republic of Nigeria, 2004, Cap 25 6. National Health Insurance Scheme (NHIS) Laws of Federal Republic of Nigeria, 2004, Cap N42 7. National Emergency Management Agency (NEMA) Laws of Federal Republic of Nigeria, 1999, Chapter N50 8. Environmental Impact Assessment Act of 2004 Laws of Federal Republic of Nigeria, 2004, Chapter E12 9. Harmful Waste Act of 2004 Laws of Federal Republic of Nigeria, 2004, Chapter H1 10. National Environmental Standards and Regulations NESREA Act (2007) Enforcement Agency Act 11. Water Resources Act Laws of Federal Republic of Nigeria, 2004, Chapter W2 12. National Environmental Protection of 1991 Federal Environmental Protection Agency Act, 1991 13. National Environmental (Construction Sector) NESREA Act (2010) Regulations of 2011

These aforementioned programmes, laws, and regulations are drivers of SD concepts, including the CE. They indicate the preparedness of the Nigerian government to achieve SD.

3.5.3 Challenges of the CE There are several challenges to the successful acceptance, adoption, transition, and implementation of the CE. Some are described in the literature as barriers. Andrews (2015) categorised barriers to the CE as practical and perceptual. The former includes the network and supply chain for disassembled components and lack of established recycled materials, while the latter refers to a common belief that recycled or remanufactured products are inferior. Moreno et al. (2015, p. 7) ranked the challenges as high, medium and low based on the perception of participants in a workshop. The highly ranked challenges are “cost restraints, consumer perception and behaviour, [and] producers and consumers locked into the current economic/market system” (p. 7). The medium ranked barriers include: “cultural expectations

93 for new models, closed loop supply chains and reverse loop supply chains [that] could increase cost of logistics, transportation and energy” (p. 7). They identified “cost restraints (lack of operational capital, lack of investment capital to develop and build new facilities), time constraints, lack of knowledge, lack of certification procedures for alternative practices, complex supply chains and complex information flows within the supply flow and unknown take back process” as the low ranked challenges. Likewise, Ghisellini et al. (2016) identified 20 challenges in their CE review, which were categorised based on the CE principles. Other barriers identified in the literature and presented in Table 3.8 revolve around consumers, industry (designers/producers), and the government.

Table 3.8: Barriers of the CE

Category Barriers References Consumers • Lack of awareness, knowledge and Rizos et al., (2015); European understanding of environmental protection Commission, (2014a); Su et al., and benefits of CE (2013); Guohui and Yunfeng (2012); Xinan and Yanfu (2011); Xue et al., (2010) • Lack of enthusiasm Preston, (2012) • Lifestyle and fashion Preston, (2012) Industry • Current products are not designed for Andrews, (2015) (Designers disassembly and • Lack of motivation to reuse or recycle Löfgren and Enocson (2014); Producers) European Commission, (2014a) • Lack of industrial symbiosis Geng et al., (2012); Preston, (2012) • Lack of a reliable system of information European Commission, (2014a); Su et al., (2013) • Scarcity of advanced technology Su et al., (2013); Xue et al, (2010); Liu et al., (2009) • Lack of CE awareness, knowledge and Silva, Rosano, Stocker, and Gorissen understanding (2017); Rizos et al., (2015); Meqdadi, Johnsen, and Joh (2012); Xinan and Yanfu (2011); Wooi and Zailani (2010); Xue et al., (2010); Liu et al., (2009); da Rocha & Sattler (2009) • Innovation challenge Preston, (2012) • Lack of appropriate quantitative tools to Su et al., (2013); Greyson, (2007); design CE Zhu, (2000) • Lack of standardisation for performance Su et al., (2013); Preston, (2012) and structures • Changes in industrial practices and Preston, (2012) consumption patterns • Lack of independent organisation to Preston, (2012) award certification on CE

Category Barriers References • Poor leadership and management Ajayi et al. (2015); Su et al., (2013); • Lack of absolute material or indicators of Geng et al., (2012) energy reduction • Reuse/recycling potential and quality Gangolells, Casals, Forcada, and Macarulla (2014); Oyedele, Ajayi, and Kadiri (2014); Da Rocha and Sattler (2009) Government • Lack of policy coherence Xue et al., (2010) • Lack of financial support Rizos et al., (2015); European Commission, (2014a); Su et al., (2013); Calogirou, Sørensen, Bjørn Larsen, and Alexopoulou (2010); Xue et al., (2010); Liu et al., (2009); Studer, Welford, and Hills (2006) • Lack of legal system on CE Geng et al., (2012) • Political obstacles to appropriate resource Tang et al. (2015); Preston, (2012); use price • High cost of green investment for firms Andrews, (2015); Rizos et al., (2015); Preston, (2012) • Weak economic incentives European Commission, (2014a); Su et al., (2013) • Lack of enforcement of legislation Su et al., (2013); Xue et al., (2010); Liu et al., (2009) • Lack of support and encouragement Calogirou et al., (2010); Struder, Welford, and Hills (2006) • Difficulties in environmental law Guohui and Yunfeng (2012) enforcement • Low taxation and prices of virgin Silva et al. (2017); Dahlbo et al. materials (2015)

As shown in Table 3.8, a lack of awareness, knowledge and understanding of the CE has been widely reported as one of the key barriers to the transition to and implementation of the CE. This applies to both consumers and industry (including producers and designers). It aligns with the survey conducted by Xue et al. (2010), which ranked a lack of awareness (64.29%) as the main barrier, followed by lack of financial support (63.48%), and lack of technology (35.71%). Liu et al. (2009) also reported limited public awareness and understanding of the CE as the main barrier to its implementation. This implies that the successful transition, adoption, and implementation of the CE in the construction industry largely depends on awareness, understanding, and knowledge of the CE among all stakeholders. This forms the basis for this research.

3.5.4 Criticism of the CE In spite of the CE’s benefits (detailed in section 3.5.1), it has been criticised for lack of clarity, definition, implementation, and failure to address one or two principles of SD. Being a new concept for organisations, industries, and governments, confusion may result from different perceptions (Gladek, 2017; Murray et al., 2017; Geissdoerfer et al., 2017; Ghisellini et al., 2016; Sauvé, Bernard, & Sloan, 2016; Lieder & Rashid 2016; Blomsma & Brennan, 2017; Lewandowski, 2016). According to Yuan et al. (2006), the CE has no consensus definition (see section 3.1.2). Lieder and Rashid (2016) noted that the CE can be defined in different ways. Similarly, Kirchherr et al. (2017, p. 229) concluded that the “CE means many different things to different people” and that no single study has provided a comprehensive definition. Therefore, the applications and interpretations of the CE are diverse (Rizos, Tuokko, & Behrens, 2017). In addition, implementation of the CE has been criticised for not transforming existing linear economy and business models (Rizos et al., 2017). Whether it is possible to implement the CE across all sectors of the economy is unclear, since it involves using durable materials and recycling or remanufacturing them at the end of their useful lives. While most materials can be recycled a limited number of times, some materials (e.g. asbestos) cannot be recycled at all. This toxicity makes it difficult to close the material loop (Robèrt et al., 2010).

Another criticism of the CE is its focus on the environmental and economic dimensions of SD and a neglect of the social dimension. Geissdoerfer et al. (2017) and Sauvé et al. (2016, p.54) argued that the CE concentrates on the environmental quality of products, while Lieder and Rashid (2016) claimed that the economic and social impacts of the CE are rarely discussed. This is supported by others (Sauvé et al., 2016; Murray et al., 2017; Moreau, Sahakian, Van Griethuysen, & Vuille, 2017). Key social issues and impacts such as fairer taxation, adaptability, and cultural heritage are not addressed in the CE (Ellen MacArthur Foundation, 2017; Murray et al., 2017; Webster, 2015). Based on these arguments, Kirchherr et al. (2017) questioned the sustainability capacity of the CE. Therefore, knowledge about its relationship with SD is relevant to improve clarity and to reveal its economic, social and environmental impacts.

3.6 CE and SD The CE is an integral part of SD. The manner in which it contributes to SD has been investigated by several authors. For instance, Geissdoerfer et al. (2017) identified the CE as a new paradigm of SD, Sauvé et al. (2016) viewed it as a useful tool for SD, while Murray et al. (2017) and Ghisellini et al. (2016) observed that it encourages organisations to implement SD.

Some authors (Ghisellini et al., 2016; European Environment Agency, 2016; Ellen MacArthur Foundation, 2013b) also refer to SD as the main aim of CE, while others view it as one of many solutions to realising SD (Kirchherr et al., 2017; Ma et al., 2014; Xue et al., 2010). As noted by Geissdoerfer et al. (2017), Sauvé et al. (2016), and Ghisellini et al. (2016), the CE presents an economic prospect to be realised through a move towards SD. China adopted the CE as a framework for economic growth, environmental change (Murray et al., 2017), material and energy efficiency (Su et al., 2013), and as a key principle in achieving SD (Shi et al., 2006). Similarly, some developed countries have also viewed the CE as a potential pathway to SD (Qian and Wang, 2016) since it encompasses economics, resources, society, and the environment (Si-yuan & Yuan, 2012). The role of the CE in achieving some SD goals (section 2.7.1) cannot be overemphasised. For instance, the CE is positioned to achieve sustainable development goal number 12 – responsible consumption and production.

Furthermore, Geissdoerfer et al. (2017, p. 14, 16) revealed the CE as a new sustainability paradigm and identified similarities and differences between CE and sustainability, which are categorised as shown in Table 3.9.

Table 3.9: Similarities between the CE and Sustainability

Category Similarities Differences CE Sustainability Origins of the Global models Different schools of Environmental term thought – C2C, movements, Government agencies – governmental and European Commission, non-governmental Non-governmental agencies organisations - EMF Goals Innovation at the core Closed loop Open-ended of system modification/design Motivation Legislation and rewards Linear to circular Diffuse and diverse as core instruments for (Resource efficiency) implementation Priority Integration in Economic system Triple bottom line development of non- economic aspects Benefit Potential cost Economic players are Environment, opportunities, risk, fundamental and economy, and reinvestment, co- environmental benefits society creation value for the society Institutionalisation Business model Focuses on economic Flexible – can be innovation – key to and environmental modified to suit industrial benefits diverse contexts and transformation aspirations

Category Similarities Differences CE Sustainability Owing to resources and competencies, they are central to private business Agency Collaboration of various Government, companies, Stakeholders stakeholders is needed and NGOs. determine priorities More organisation for Theoretical optimisation Sustains current various and coexisting limits and practical status indefinitely development paths implementation limits Perceptions Technological solutions Private business and Shared but not are crucial but regulators/policy makers defined sometimes create responsibilities problems with implementation Commitments Intra and Less environmental Interest alignment intergenerational pollution, resource between commitments consumption, and huge stakeholders Multi-/interdisciplinary economic advantages for research field companies Source: Adapted from Geissdoerfer et al. (2017, p. 14, 16)

CIRAIG (2015) summarised the relationship between SD and CE, indicating that the former incorporates the economic and environmental approaches of sustainability into the latter while the social dimension is achieved through organisations’ corporate social responsibilities (CSR). Overall, the CE is one of several concepts that organisations involved in manufacturing and production can adopt to achieve SD.

3.6.1 Environmental Impacts of the CE The environmental impacts of the CE are its strength and the potential reason for its consideration, adoption, and implementation by businesses, industries, and governments. According to Persson (2015), the CE is regarded as a novel solution to environmental issues, resulting in positive impacts. The majority of these have been identified and described in literature. For instance, Geng et al. (2012, p. 221) identified five attributes of the CE, which include: “conservation of natural resources (especially non-renewable resources such as water, fossil, fuels and minerals), reduced environmental impacts through efficient energy and material and less water discharge, avoidance of toxic materials, extended life cycle of landfill sites, and recovery of local ecosystems”. The CE can reduce the input-output flow of virgin materials by using renewable energy sources and reduce material waste and emissions (Korhonen, Honkasalo, & Seppälä, 2018). Also investigated were the CE’s potential opportunities to reduce negative environmental impacts resulting from industrial activities. For

example, a study by the Ellen MacArthur Foundation and McKinsey Center for Business and Environment in 2015 estimated a decrease of virgin materials used in industries such as car, construction, and agriculture to be about 32% and 53% by 2030 and 2050 respectively.

Furthermore, an Ellen MacArthur Foundation (2015b) study (using Denmark as a case study) estimated that country’s carbon footprint could be reduced by 3–7%, with consumption of raw materials being as low as 5–50%, by 2035. In addition, a study by Moon and Holton (2011) showed that material waste minimisation and cost savings are potential positive impacts of the CE when adopted in the building construction industry. Other environmental impacts of the CE are presented in Table 3.10. Table 3.10: Environmental impacts of the CE

Environmental Impacts of CE References Waste minimisation Andersen , 2007; European Commission, 2017; European Environmental Bureau, 2014; Moon and Holton, 2011; Lieder and Rashid, 2016; Ghisellini et al., 2016 Resource minimisation/efficiency Andersen, 2007; Korhonen, Honkasalo and Seppälä, 2018; Lieder and Rashid, 2016; Song and Li, 2012; Shi et al., 2006; European Environmental Bureau, 2014; Lawton et al., 2013; Jones and Comfort, 2018; Prieto-Sandoval et al., 2018 Reduce environmental pollution Wang, 2009; Prieto-Sandoval et al., 2018; Jawahir and Bradley 2016 Improve eco-efficiency Yuan et al., 2006 Extend lifecycle of landfill sites Geng et al., 2012 Conserve natural resources Preston, 2012; Zhu et al., 2010; Geng et al., 2012; Reduce emissions e.g. carbon dioxide, Ellen MacArthur Foundation, 2015a; Geng et al., toxins 2012; Jones and Comfort, 2018; Prieto-Sandoval et al., 2018; Lieder and Rashid, 2016; European Commission, 2015 Prevent environmental poverty Zhijun and Nailing, 2007 Energy efficiency Geng et al., 2012; Andersen, 2007; Korhonen, Honkasalo and Seppälä, 2018; Gaspar et al., 2018; Ghisellini et al., 2018; Shi et al., 2006; European Commission, 2017 Reduce lifecycle impacts of buildings Ghisellini et al. (2018) through reuse, recycling and refurbishing principles

3.6.2 Economic Impacts of the CE A study by Kirchherr et al. (2017) revealed that 46% of definitions identified economic wealth as the main aim of the CE, while 53% of professionals mentioned it in their definitions. This

suggests that the economic impacts of the CE are considerable and may be a key stimulant in its adoption and implementation. To achieve this aim is to “reduce the economic production- consumption system’s raw material and energy costs, waste management and emissions control costs, risks from (environmental) legislation/taxation and public image as well as to innovate new product designs and market opportunities for businesses” (Korhonen, Honkasalo and Seppälä, 2018, p. 41). Others note that economic opportunities, including resource productivity, material cost reduction, and increased revenue from waste sales (Yuan et al., 2006; Moreno et al., 2015; Geng et al., 2012), are linked to the CE. It is possible to achieve economic growth without extracting additional resources (Ghisellini et al., 2016; Persson, 2015; Jun & Xiang, 2011; Zhu et al., 2010), allay demand-driven price volatility of raw materials (Crowther &Gilman, 2014), and create new business models, thereby increasing profits (Moreno et al., 2015). Consequently, the CE was recognised as an economic approach to achieving SD (CIRAIG, 2015; Ellen MacArthur Foundation, 2013a) while accomplishing other benefits such as job creation and direct cost savings to businesses, offering reputational advantages and becoming a market differentiator without placing undue pressure on resources (Benton et al., 2014), business model creation, and overall economic gains (Antikainen & Valkokari, 2016).

The Ellen MacArthur Foundation (2013a, 2014) has suggested that a move towards reparability and maintenance of products resulting from the adoption of the CE would create more jobs. In addition, the Ellen MacArthur Foundation (2015a) revealed that with an increase of about 30% in resource productivity, the CE could boost gross domestic capital by 1%, creating an additional two million jobs globally by 2030. In support of this claim, Rizos et al. (2017) observed that if the current rate of development around the CE is steady, 200,000 new jobs per annum could be created by 2030. Wijkman and Skånberg (2015) proved that reducing carbon emissions would accelerate job creation, thereby increasing GDP. The Ellen MacArthur Foundation (2015a) assumed that businesses operating the CE could save $630 billion in material costs by 2025. Similarly, Esposito et al. (2018) claimed that a company recovering and remanufacturing products could reduce material use by 90% while increasing profits by 50%. The CE has the potential to generate economic gains that have been analysed in literature. For example, the European Commission estimated that transitioning to the CE in the manufacturing sector alone could generate economic gains worth €600 billion annually (Ellen MacArthur Foundation, 2013a; CIRAIG, 2015). As revealed by Finland’s Independence Celebration Fund and McKinsey (2014), full implementation of the CE at the global level

100

would lead to annual financial gains valued at 1000 billion USD. An estimate provided by Lacy and Rutqvist (2016) reveals that turning waste to energy would create about $4.5 trillion by 2030, but was silent on the cost of burning waste. In addition, it could drive a country’s biomass resource market, estimated to be $80 billion.

The economic projections resulting from the adoption and implementation of the CE in some countries are considerable. In the UK, it is projected that companies could benefit annually from low cost resource efficiency of up to £23 billion, while the value of the efficient use of resources could reach $3.7 trillion yearly based on the Department for Environment, Food and Rural Affairs’ (DEFRA) calculations. Likewise, ESA (2013) forecast investments worth €12 billion and 50,000 new jobs in the recycling, deconstruction, and waste treatment sectors in the UK. In the Netherlands, the successful transition to the CE, especially in the base metal, electrical, and biotic waste management sectors, is estimated to have created about 54,000 jobs (Bastein et al., 2013). A case study of the economic impacts of the CE on five sectors in Denmark, including construction and real estate, plastic packaging, food and beverages, machinery, and hospitals, revealed an increase of about 3–6% in economic value, 13,000– 17,000 jobs, and estimated that a 0.8–1.4% GDP rise is possible by 2035 (Ellen MacArthur Foundation, 2015b). In Finland, annual economic gains resulting from the adoption of the CE is estimated to be €2.5 billion (Finland's Independence Celebration Fund (FICF) and Mckinsey, 2014), while in the EU about 1.4–2.8 million jobs could be created by 2020 (Ellen MacArthur Foundation, 2013a). With such enormous economic potential, it would be appropriate for developing countries to investigate the CE for later adoption and implementation.

3.6.3 Social Impacts of the CE The CE presents an appropriate model to achieve SD. It has been criticised, however, for failing to mention the social aspects of SD and concentrating on its economic and environmental aspects (Murray et al., 2017). Several authors (Ellen MacArthur Foundation, 2017; Moreau et al., 2017; Murray et al., 2017; Sauvé et al., 2016) have claimed that social equity is ignored in the CE and, as such, social impacts remain unknown, especially as they relate to SD. According to Murray et al. (2017), humankind benefits from resource conservation while the biosphere benefits from the redesign of production and service systems. Nevertheless, “there is no explicit recognition of the social aspects inherent in other conceptualisations of sustainable development” (p. 8). Murray and colleagues questioned how the CE might contribute to social equity and equality. They critiqued the idea of designing durable products, claiming that the

101

design may be compromised and that longevity in products is ecologically inefficient because products consume more energy than entropy during their life span.

The social objectives of the CE, including job creation, educational opportunities, and improved employment conditions (Ellen MacArthur Foundation, 2013b) are intended to benefit society. Through the sharing economy, which encourages social interaction among members of the community, resource efficiency and reducing pollution can be achieved (George et al., 2015; Korhonen, Honkasalo & Seppälä, 2018). The CE is often termed the sharing economy, indicating that it is socially constructed (Pomponi & Moncaster, 2017). It has the potential to meet present and future social needs, thus contributing to SD. Some impacts of the CE highlighted in the literature are closely related to behavioural intentions. For instance, it is believed that the CE can create opportunities for collaboration and cooperation between consumers and producers as well as between different stakeholders (Persson, 2015; Yuan et al., 2006). Similarly, it encourages improved relationships between industrial sectors and local societies while developing the socioeconomic status of a nation (Geng et al., 2012) and networks for reuse and resource sharing (Beavis, 2015; Faraud, 2016). In addition, Su et al. (2013) observed that the CE can strengthen national security by increasing sustainable energy supply. Resource efficiency as an important characteristic of the CE would indirectly improve societal wellbeing (Ness, 2008) while integrating communities, closing income gaps, and promoting social justice (Zhijun & Nailing, 2007). Based on the CE business model, where products are built to last and are used as a service, unethical practices and behaviours would be reduced (Andrews, 2015). Likewise, circular supply chains may contribute to the selection of ethical suppliers and corrupt suppliers may be encouraged to change their behaviours. It is clear that the CE creates an environment in which individual and organisational behavioural changes occur.

3.6.3.1 Behavioural Impacts of the CE The CE has been described as a paradigm shift in societal behaviour impacting the manufacture and consumption of goods and services. It encourages a significant change in how products are sourced, used, and disposed of (RSA, 2013). Hislop and Hill (2011) assert that a change in consumption behaviour is essential for a smooth transition from a linear to a circular model. Ghisellini et al. (2016) posit that the dynamic participation of both consumers and producers in environmental protection through reuse and recycling is vital for the CE. Similarly, Lieder and Rashid (2016) see social awareness as playing a significant part in the transition from a linear to a CE. However, Pomponi and Moncaster (2017) observe that the discussion around 102

behavioural dimensions of the CE is limited, stressing its significance especially in the sustainability of the built environment.

Consumer and producer behaviour has been identified as one of the threats to transitioning to the CE (Corbey, Cullen, Sansom, & Fishwick, 2016). On the other hand, it may be viewed as contributing to mitigating environmental impacts, including carbon and energy reduction (Daly, 2015), attitudes towards material reuse and recycling (Adams, 2016; Owens, 2016; Corbey et al., 2016; Overbury, 2015; Khoo, 2015;), and awareness of low carbon buildings and technologies (Fieldhouse, 2015). This indicates that behaviour, including the awareness, perceptions, and attitudes of consumers and producers, is key to the successful implementation of the CE. Cohen-Rosenthal (2000) observed that consumers’ perceptions of the added value of products would determine the implementation of the CE. Therefore, efforts to raise consumer awareness require a behavioural change and a redirected focus on products’ value and performance rather than ownership (Lieder & Rashid, 2016). For instance, Matus, Xiao, and Zimmerman (2012) observed that consumers in China are becoming increasingly aware of products’ components and properties, which has encouraged environmental consciousness behaviour. This shift in consumers’ behaviour could improve operations of the product-as-a- service and sharing platform of the CE business model. It could also accelerate effective functioning of take-back systems, which may require manufacturers or producers to provide incentives for consumers to return used products (Rizos et al., 2017). Some authors (Webster, 2015; Jackson, 2007) also supported the idea of incentives as well as education and engagement in changing consumers’ behaviour.

In embracing circularity, Pomponi and Moncaster (2017) argued that a change of behaviour is not about technologies but about the people. This further attests to the fact that technologies are a means to an end and not an end in themselves (e.g. technology is a tool to achieve SD). Therefore, the adoption of technologies with appropriate attitudes and perceptions are fundamental parts of the CE and SD. The role of policy in influencing people’s behaviours and lifestyles has emerged in literature (Jackson & Michaelis, 2003). The introduction of legislative policies may stimulate awareness to protect the environment through various sustainable concepts and approaches. This suggests that in realising the CE and SD, policies play a significant role. For instance, China’s CE promotion law was aimed at influencing behaviours at three business levels – micro, meso, and macro (Geng et al. 2009; Yuan et al. 2006). Some other countries (including USA, Australia, and Germany) have implemented similar policies, requiring manufacturers to take full responsibility for the disposal of their products. It is

103

apparent that a shift to closed-loop consumption behavioural patterns supported with appropriate technology and incentives could fast-track the smooth transition and implementation of the CE.

3.6.4 Technological Impacts of the CE Technological initiatives support the social, environmental, and economic characteristics of the CE. They need to be explored as possible solutions to minimising negative environmental effects arising from the production and consumption of products. Several studies have highlighted the importance of technological innovations, information, and infrastructure for the CE and how the CE could trigger advanced technologies. For instance, Andersen (2007) argued that the CE provides opportunities to increase innovation and adopt cleaner technologies to ensure resource efficiency and waste minimisation. Preston (2012) suggested that the CE could assist in industrialisation through industrial symbiosis. Additionally, the Ellen MacArthur Foundation (2015a) revealed that advanced technology allows for efficient knowledge sharing, collaboration, reverse logistics, and material tracking, which are necessary to implement the CE. There are also technological solutions that have been developed, such as advanced materials, nanotechnology, Internet of Things (IoT), big data, mobile internet, and renewable energy. These support the CE by reducing waste and conserving energy (Timmermans, 2015). Other technological innovations, including 3D printing of products such as bricks and cardboard ductworks (Simpson, 2016), design for manufacture and assembly (O’Rourke, 2016), and design for deconstruction or disassembly (Adams, 2016; Tingley & Davison, 2011), are also vital for reducing and stabilising demand for resources while satisfying human needs (Ehrenfeld, 2004). As suggested by Bakker et al. (2014), technological innovations in design can minimise raw materials and energy demand and also increase a product’s lifespan. In addition, Pomponi and Moncaster (2017) observed that technology, as a key aspect of the CE, facilitates data management, demand and supply, and recycling, while Deutz and Gibbs (2008) suggested that innovative technologies should be developed at each stage (macro, meso, and macro) of a business. It is important for businesses to explore technology as a means of transitioning from linear approaches to the CE.

3.7 The CE and the Construction Industry The CE concept is yet to be adopted in the construction industry. However, there are possible ways the CE can be adopted in the construction. One of these is waste minimisation. The following sections identifies the opportunities, practical approaches and steps towards adopting

104

the CE in the construction industry. These explain the relationship between the CE and the construction industry.

3.7.1 Opportunities for Circularity in the Construction Industry The activities of the construction industry contribute greenhouse gas emissions, and generate waste, noise, and dust (Zuo et al., 2012). The CE potentially mitigates against these impacts and, according to Stahel (2016), is a framework that ensures efficient use of materials, minimises waste, extends a product’s life, and reduces carbon emissions. These are opportunities that the construction industry can benefit from to minimise environmental pollution and to achieve SD. The adoption of the CE in the construction industry has been referred to as circular construction (van Sante, 2017). In addition to the construction industry, the real estate industry has been acknowledged as a sector with the “highest potential” in the CE (Ellen MacArthur Foundation, 2015b, p. 111). Liu, Liang, Song and Li (2017) also considered the CE as an appropriate approach for managing construction waste by reusing products. Likewise, previous studies (Huang et al., 2018; Nuñez-Cacho et al., 2018; Esa et al., 2017) have proposed that the CE, via the 3R principles (reduce, reuse, and recycling), can be used to effectively evaluate and address construction and demolition waste.

Through the CE, construction waste can be reused while virgin raw materials can form parts of new components (de Figueirêdo Lopes Lucena et al., 2013). This implies that construction waste may be considered as an asset. Uygunoğlu et al. (2014) observe that the reuse of materials, or their conversion to other products, would cut industrial production processes and, as such, energy inputs would be reduced. Duran, Lenihan, and O’Regan (2006, p. 305) argued that recycling “takes place as long as construction and demolition wastes producers find it cheaper than landfilling and as long as users of construction aggregates find recycled aggregates cheaper and of similar quality than newly quarried aggregates”. This implies that recycling may be adopted to minimise construction waste. Nevertheless, it should not be the main focus of the CE. It should, rather, be an end-of-pipe solution when reuse is uncertain (van Sante, 2017) because it uses energy and does not include energy recovery (Moreno et al., 2015; European Union, 2008). Therefore, the reuse of materials appears to be preferable to applying the CE (Moreno et al., 2015). The Danish city of Kalundborg (where companies reuse each other’s waste products) illustrates how these principles have been applied (Damen, 2012). It has been suggested that construction professionals, including architects, engineers, and contractors, maximise the use and reuse of materials at the design stage and throughout the supply chain (van Sante, 2017) by designing out waste (Govindan & Hasanagic, 2018).

105

Smol et al. (2015) identified change in design as one of the actions required by the construction industry to transition to the CE. As indicated by Murray et al. (2017), products may be repaired and restored by designing suitable systems. Arup and Bam (2017) suggested that circular design should be incorporated into projects at the design stage to leverage opportunities such as the production of durable products that are easy to maintain, repair, refurbish, upgrade, remanufacture, and recycle. This would divert waste from landfill, which could help construction firms save on waste management costs (Arup and Bam, 2017). The need for appropriate policies to support moves to the CE by construction organisations has been advocated by Ghisellini et al. (2016). Such policies are likely to contribute to waste minimisation and encourage behavioural change towards waste generation. For example, the European Commission’s policy for the CE has been effective in closing loops in the built environment (Bourguignon, 2016).

Despite the potential benefits the CE offers the industry, some challenges are impeding the transition process. Challenges relating to construction products, buildings as infrastructure, product recovery, and business concerns have been identified by Thornback and Adams (2016). Adams et al. (2017) acknowledged that the adoption of a CE in the construction industry is hampered by some important challenges. These include a lack of knowledge and clarity of the CE, limited awareness across the supply chain network, absence of market mechanisms for recovered materials, inability to differentiate between reuse and recycling, lack of incentives for designers, and lack of interest. Other challenges include lack of secondary markets for used materials and lack of quality regulatory agencies for recycled products (Construction Products Association, 2016). Likewise, the UK Green Building Council (2018) revealed that many construction professionals are struggling to change the status quo. They find it difficult to adopt the CE business models despite being aware of campaigns and initiatives to inspire circular thinking and design. Jones and Comfort (2018) suggest that, rather than focusing on material waste and recycling, the entire construction supply chain should be involved in making the CE a reality in the industry. In support, the European Construction Industry Federation (2016) has argued that both the demand and supply of materials are to be considered along with the wider acceptance of stakeholders and relevant markets. Overall, adoption of the CE in the construction industry is very challenging (Vladimir & Przemysław, 2017). However, appropriate policies and mechanisms, such as continuous training, education, awareness, incentives, and business models, are preconditions for successful implementation of the CE (Heshmati, 2015; Lieder & Rashid, 2016).

106

3.7.2 Practical Approaches to the CE in the Construction Industry Adoption of the CE in the construction industry is gaining traction. Several approaches are required for its implementation including extending a building’s life span, designing buildings with fewer materials, specifying bio-based construction materials, using buildings as a “building bank” at the end of their life, and “material passports” (van Sante, 2017, p. 17). In addition, Ghisellini et al. (2018) identified factors that facilitate the industry’s implementation of the CE. These include design, building type, selective demolition, building element type, material type, location of building, scale of recycling plants, market availability for salvaged goods, economic setting, and political context. For this study, the CE approaches that are practicable and related to the construction industry have been identified in section 3.3. They include design, construction methods, policies, LCA, business models and the 3R principles. These approaches are interrelated and are explored in the following sections.

3.7.2.1 Design Approaches The overarching aim of CE design approaches in construction is to design out waste. This echoes the importance of material reuse and extending a buildings lifespan via flexible spaces and use of adaptable elements (Allwood, 2016). To achieve this aim, building materials need to be designed for reuse and for recycling (Andrews, 2015), while buildings themselves need to be designed to be deconstructed (Desai & Mital, 2005). The circular design approach requires a change in the status quo but has been resisted by designers and builders (Sanchez & Haas, 2018a). Hunter (2013) observed that designers focus their creative abilities on designing and creating artefacts that are aesthetically pleasing. Most designers do not consider how they could prevent used products from being sent to landfills as this was never called for. Furthermore, Hunter (2013) advocated for an understanding of the CE, claiming that design briefs will soon require circular design for materials. The lifespan of buildings can be extended by designing them to last longer using resilient materials and superlative construction standards, thereby reducing the cost of maintenance in the long run (Rizos et al., 2017). Therefore, a shift to circularity in design is important for a transition to CE. There are certain conditions that need to be considered during design, including material selection, design for easy end-of-life sorting, design for durability, design for ease of manufacturing, use of standardised components, and separation of materials for reuse (Ellen MacArthur Foundation, 2013a). These are necessary to prevent material waste generation (Esa et al., 2017) and to ensure resource efficiency (Esposito et al., 2018).

107

Bakker and Hollander (2013), Esposito et al. (2018), and RSA (2013) identified design strategies that extend a product’s life, create a closed loop economy, and ensure circularity in the construction industry. These are listed below:

• Design for off-site construction: As an effective approach to minimising construction material waste on site, it ensures that building elements are prefabricated, delivered to site and coupled together. • Design for material optimisation: This approach takes into consideration material supply chain logistics, including construction site location, transportation, packaging and delivery. Further, it identifies efficient use and service life expectancy of materials. • Design for waste-efficient procurement: In this approach, probable waste that could be generated from different construction activities is analysed and prevented during procurement. • Design for flexibility and deconstruction: This approach creates a process through a planned system that minimises waste and ensures reuse and recovery of materials. • Design for reuse and recovery: In this approach, different building elements that can be reused, recycled, remanufactured, and returned at their end of life are considered. The elements may include component parts, materials, and packaging. • Design for product attachment and trust: In this approach, products are designed with high safety features and top quality, which makes users personalise and trust them. Such products are designed to be attractive to potential users. • Design for product durability: This approach ensures products are designed to last for as long as possible to improve reliability. • Design for standardisation and compatibility: This approach ensures products are designed to standards and are compatible with other products. • Design for ease of maintenance: As an effective approach to enhance products’ durability, it ensures products can be easily repaired or maintained. • Design for upgradability and adaptability: This approach ensures that the current functions of products can be adjusted to suit future needs, thereby making such products flexible and minimising demand for new products • Design for disassembly and reassembly: This approach takes into consideration the end of life option of products by ensuring that they can be easily disassembled and reassembled.

108

Designing for circularity in construction is complex (Hunter, 2013) because a product’s life span and end of life are considered at the start of the design cycle (Circle Economy, 2012). This is closely related to design for sustainability but extends beyond product recycling (Circle Economy, 2012).

While there are several design approaches, there are limited examples of where they have been applied (Thornback & Adams, 2016). This may be due to numerous reasons, including a lack of knowledge about design for circularity, a lack of awareness about waste efficient designs, lack of experience, training deficiencies, resistance to change in practice, and lack of technical know-how (Ajayi, 2017). Therefore, it is important that design techniques for minimising material waste adopted by building designers are explored to better understand the problem.

3.7.2.2 Reuse and Recycle Approach Reuse and recycle are principles of the CE that have been adopted in the construction industry, which suggests they are important for the transition to a CE. In a study conducted by Ng and Chau (2015), they found that recycling, reuse, and incineration of building materials could save about 54%, 6.22%, and 0.44% embodied energy respectively and, as such, they concluded that recycling has the most potential to save energy for materials with a high concentration of concrete. In addition, steel and concrete can also be recycled (Van Erp and Rogers, 2008; Tam, 2008b; Yellishetty, Mudd, Ranjith, & Tharumarajah, 2011). On the other hand, Ng and Chau (2015) revealed that for doors and windows, reuse is a better option than recycling, while for other materials, such as roof structures and walls, both recycling and reuse are suitable.

Reuse of materials has been considered a key strategy in closing the material waste loop (Stahel, 2016; Brown & Buranakarn, 2003; Allwood et al., 2012), and of higher energy efficiency than recycling (Allwood et al., 2011). From an economic point of view, Diyamandoglu and Fortuna (2015) observed that materials salvaged from deconstruction processes have more value in terms of cost than new materials, when such materials are diverted from being recycled. For instance, leftover gas pipelines were used for the construction of the 2012 London Olympic stadium, which saved about 2500 tonnes of new structural steel (Rizos et al. 2017). Materials that are old or broken may be restored or repaired. According to Vilches et al. (2017), restoration is not only applicable for old materials but could be applied to complete buildings. Repair involves fixing broken parts of a material or an entire building. Similarly, some authors (Gaspar & Santos, 2015; Ferreira et al., 2015) have shown that, from

109

an economic and environmental perspective, the refurbishment of buildings is a better option than building new ones. Reuse of disassembled materials has also been identified as a major step towards the CE (Aye, Ngo, Crawford, Gammampila & Mendis, 2012). In addition, Al- Obaidi, Wei, Ismail and Kam (2017) observed that it is possible to reuse a whole building which, in turn, reduces demolition and the volume of materials sent to landfill. Despite the benefits of recovering materials and reducing energy and waste, recycling is subject to some barriers, including those that are economic, information-related, managerial, and legislative. These prevent the effective management and use of recycled products (Esa et al., 2017; Silva et al., 2017; Gangolells et al., 2014; Lu & Yuan, 2010). It is crucial to mitigate these barriers in order to effectively actualise the CE in the construction industry.

3.7.2.3 Construction Methods There are different approaches to minimising construction material waste and ensuring circularity in the industry. The lean production method is one such approach. It can be applied through building information modelling (BIM) and has demonstrated efficiency in waste reduction (Sacks, Radosavljevic, & Barak, 2010). In an ideal BIM world, detailed information about each building element, the relationship between elements and the entire building is provided while the location of material components within the building can be tracked (Ashcraft, 2008; Catalli & Williams, 2001) from procurement to installation (Wu, Xu, Mao, & Li, 2017) with a view to providing a reliable basis for decision making. Another approach is green supply chain management, which seeks to reduce pollution by considering the environmental and economic performance of materials before they are procured (Ying & Li- jun, 2012). With this approach, long-lasting components can be disassembled at their end of life and redirected back to the supply chain (Wheaton, 2017). Conversely, they can be remanufactured but may require standardisation and the elimination of toxins (Rizos et al., 2017). According to Arge (2005), building adaptability is driven by the use of standardised materials. These materials can be sold for use within the industry or in other industries (WRAP, 2009c).

Prefabrication of the components or elements of a building structure are considered important in closing the materials loop. Since production takes place in one location off site, there is an appropriate inventory of all materials supplied (Minunno et al., 2018). This approach, and the use of light steel frames, has been recommended for new construction projects (Haas, Krausmann, Wiedenhofer, & Heinz, 2015) based on their significant roles in contributing to a flexible structural system (Sanchez & Haas, 2018b). Prefabricated construction is not novel

110

and there are diverse examples around the world. Since elements are constructed off site and assembled on site, prefabrication encourages deconstruction of elements and components at their end of life. A practical example is the construction of the 2012 London Olympic park, which was deconstructed after the games (Rizos et al., 2017). Although these aforementioned approaches can increase circularity in the construction industry, reduce waste, and close material loops, they are mostly applied in theory and not in real-life cases (Galle, de Temmerman, & de Meyer, 2017). The transfer of knowledge to real-life scenarios, lack of awareness, lack of experience, limited technology, and other factors that are industry- or country-specific may be responsible (Xiahou, Yuan, Liu, Tang, & Li, 2018; Xue, Zhang, Su, & Wu, 2017). Therefore, there is a need to identify these obstacles and study the current construction approaches to achieving the CE in the construction industry.

3.7.2.4 Business Model Approach As discussed in section 3.3.2, the sharing platform and PaaS business models of the CE alongside others (circular supply chain, building products to last, and recovery and recycling) are applicable to the construction industry. Application of the sharing platform and PaaS models have been discussed in the literature. For instance, a study by Jones and Comfort (2018) reveals that Salvo, a company that trades in Europe, offers a take-back scheme for architectural antiques including doors, windows, stained glass, fireplaces, ironwork, radiators, and lighting. Likewise, sharing, repurposing, and mixed-use of building spaces have been encouraged by the Ellen MacArthur Foundation (2015a, 2016) to ensure efficient use of floor spaces. According to Zuidema (2015), open building is a design approach that considers the possibility of changing a building structure in future and, as such, is described as the basis for CE buildings, which differentiates convertible and flexible building structures from long lasting ones. Zuidema further explained that through PaaS and diverse ownership models, such as leasing and renting, replaceable parts of the built environment can be provided. From an economic perspective, adopting any of the CE business models could save costs for construction firms. A study conducted in China by Liu and Wang (2013) compared the cost of construction waste disposal, material recycling, and recycling for reuse purposes. The study found that the cost of recycling for reuse was the lowest and, as a result, ARUP (2016) recommended that organisations should anticipate reusing and re-purposing buildings. This suggests that reuse in the form of material exchanges (sharing economy) would encourage development of materials that are long lasting.

111

3.7.2.5 Waste and Energy Measurement Tools The volume of construction materials that enters and remains in the building stock is alarming (Ness & Atkinson 2001; Kennedy, Cuddihy and Engel-Yan, 2007). To assess and evaluate the input and output of waste and energy resulting from these materials, various tools have been established. According to Ghisellini et al. (2018) the life-cycle assessment (LCA) model can be used to evaluate and improve CE implementation in the building sector using the Cradle to Cradle processes. Pomponi and Moncaster (2016) described an analytical framework that evaluates environmental sustainability at the micro, meso and macro levels, which deals with building materials, buildings, and urban fabric respectively. In addition, several authors (Kohler & Yang, 2007; Huang & Hsu, 2003) have identified material flow analysis (MFA) as a tool for managing building stock efficiently by measuring “net additions to stocks” (new materials added to building stock) (OECD, 2008, p. 11). ARUP (2016) also suggested that digital technologies, including the Internet of Things (IoT), can be used to assess the performance of fittings and fixtures such as LED light bulbs for buildings. Similarly, Minunno et al. (2018) observed that prefabricated buildings can be enhanced to create a closed-loop supply chain by integrating radio frequency identification (RFID) systems into them. These tools could form part of the CE for assessing and evaluating waste and energy within the construction industry.

3.7.2.6 Policies The influence of policies in adopting the CE in the construction industry is significant. Some of the CE policies that have been introduced in the manufacturing industry may apply to the construction industry. Some specific policies relate directly to the construction industry. For example, the polluter pays principle is aimed at encouraging producers and users to reduce waste generation and cost of disposal by taking full responsibility for disposal (Duran, Lenihan, & O’Regan, 2006). Some waste management and recycling policies as introduced by construction firms may contribute to the CE (Vinci, n.d.).

3.7.3 Practical Steps towards the CE Several factors are required for the widespread acceptance of the CE and to support the changes required at the production level (Crowther & Gilman, 2014) or construction phase. Five enablers were identified by the Ellen MacArthur Foundation (2013a), which are:

i. Cross cycle and cross value chain collaboration (i.e. two or more companies working together to deliver value)

112

ii. Incentives alignment (i.e. sharing the risks, costs, and rewards equally among all stakeholders) iii. Provision of suitable sets of international environment rules iv. Access to financing and risk management tools v. Leading by example and accelerating the spread of circular setups

These factors apply to the construction industry. Incentives may be provided for designers to design buildings with less waste (Ajayi, 2017). Contractors may be rewarded for effectively utilising materials that reduce waste (Tam, 2008b, Tam & Tam, 2008). Crowther and Gilman (2014) identified other enabling factors, including regulation, infrastructure development and education. The latter is to increase clients’ awareness and “to create the skill base to drive circular innovation” (p. 18). This should not be for clients alone but for all construction stakeholders as they are expected to apply their expertise to projects and educate their clients. Webster (2015) emphasised that education is a fundamental element of the transition to the CE and for it to be successful, the full support of users/consumers, educational institutions, and policy makers is required (Ellen MacArthur Foundation, 2013b). Hunter (2013) identified a range of stakeholders needed to transition to the CE, as presented in Table 3.11.

Table 3.11: The CE network

Category Key stakeholders Design System Thinkers Design Engineers Product & Industrial Architects & Interior Transport Communications & Digital Fashion & Textile Service Makers & Fixers Consumers and Users Consumers Marketers Anthropologists Advertising Agencies Brands/Companies Retailers Consumers facing manufacturers Construction companies Consumers facing brands Manufacturers B2B Component Manufacturers Brand licenses Material Manufacturers Material Experts Raw materials

113

Category Key stakeholders Material Scientists Chemists Material Technologists Resource Management Repair, Refurb, & Remanufacture Landfill Managers Recycling Facilities Material Recovery Policy Makers Local Authorities Standard Regulators Policy Writers Public Procurement Government Think Tanks Campaigners Press & Media Investors Business Investors Venture Capitalists Entrepreneurs PLC Leaders Academics and Education Research Councils Academics & Researchers HE & FE Course Leaders Apprenticeship Leaders Source: Adapted from RSA (2013)

3.8 Theoretical Perspective of the CE There are several theories that support and inform an understanding of the transition to the CE. The diffusion of innovations (DOI) theory has been found appropriate for this study because it relates to behaviour that is important in transitioning to the CE. In addition, the DOI is applicable to many disciplines and fields of study (Dearing, 2009). It has been employed for construction management related studies by researchers such as Kale and Arditi (2005, 2006, 2010), Taylor and Levitt (2004, 2007), Larsen and Ballal (2005), Widen and Hansson (2007), and Peansupap and Walker (2006).

3.8.1 Diffusion of Innovations Theory Among the numerous theories and models that inform the adoption of technological innovations, the DOI theory developed by Everett Rogers is popular and influential. The theory has been considered in different fields, such as political science, communications, history, public health, technology, construction, and education (Stuart, 2000; Dooley, 1999). Rogers (2003, p. 177) described adoption as “full use of an innovation as the best course of action available” while diffusion implies “the process in which an innovation is communicated

114 through certain channels over time among members of a social system” (p. 5). The acceptance or rejection of an innovation is based on choice and each individual’s decision. According to Rogers (2003) the key components in the DOI are communication channels, time, social system, and innovation.

Innovation, as defined by Rogers (2003, p. 12), is “an idea, practice, or project that is perceived as new by an individual or other unit of adoption”. Rogers categorised innovation as tangible and intangible, the former being physical objects (e.g. fire alarm systems, heat extractor) while the latter includes non-physical objects such as new construction methods, techniques, or designs. According to Rogers’ definition, an innovation perceived as new in one geographic area could be considered obsolete in a different region. However, the diffusion and adoption of an innovation depends on the “consequence,” which Rogers (2003, p. 436) described as “the changes that occur in an individual or a social system as a result of the adoption or rejection of an innovation” which could be anticipated or not. The consequences of an innovation are important and every individual or social system needs to be aware of them, hence the need for communication.

Communication channels are modes through which innovation information is disseminated. In the words of Rogers (2003, p. 5), communication is “a process in which participants create and share information with one another in order to reach a mutual understanding”. It therefore requires a source, a medium, and a receiver(s), where the source is the originator of the message while the medium is what conveys the message to the receiver. For communication to be effective, there must be feedback (Figure 3.8). Diffusion as a social process can be communicated through interpersonal relationships (Rogers, 2003) developed over time. As a result, time becomes an important factor. It is often ignored in most behavioural research but its inclusion in diffusion research shows its importance as the innovation-diffusion process is executed over time (Rogers, 2003). Therefore, a considerable amount of time may be required to impact a social system.

Rogers (2003, p. 23) described a social system as “a set of interrelated units engaged in joint problem solving to accomplish a common goal”. As shown in Figure 3.8, it can be deduced that DOI is subjective to social systems. However, an individual’s innovativeness is affected by the nature of a social system (Rogers, 2003). The process of innovation-decision is to consider accepting or rejecting an innovation, which Rogers (2003, p. 172) described as “an information-seeking and information-processing activity, where an individual is motivated to

115 reduce uncertainty about the advantages and disadvantages of an innovation”. Rogers identified five stages (Figure 3.8) involved in innovation-decision making processes: knowledge, persuasion, decision, implementation and confirmation. This process follows the stated sequence.

As presented in Figure 3.8, knowledge is the first stage of the process of innovation-decision. An individual seeks details, including an innovation’s advantages and disadvantages. In this stage, questions like ‘what’, ‘why’ and ‘how’ are prominent (Sahin, 2006). Rogers (2003) indicated that these questions are the basic types of knowledge – awareness-knowledge, how- to-knowledge, and knowledge-principles. The knowledge of an innovation by an individual or society is influenced by social system variables and receivers’ variables (Figure 3.8).

Figure 3.8: Diffusion of Innovation model Source: Rogers (1995) The next stage, persuasion, is where an individual develops interest in an innovation. According to Rogers (2003), an individual’s attitudes play a significant role in this stage. Rogers, however, suggested that “the formation of a favourable or unfavourable attitude towards an innovation does not always lead directly or indirectly to an adoption or rejection” (p. 176). Rogers further emphasised that this stage is affective (having to do with one’s feeling), while the knowledge stage is cognitive (knowing about something), but opinions and beliefs

116

about an innovation may be affected by perceived characteristics of innovations (Figure 3.8), uncertainty about innovation and social reinforcement from others (Rogers, 2003).

The persuasion stage is closely followed by the decision stage, which deals with acceptance (adoption) or refusal of an innovation. Rejection is the opposite of adoption and simply means “not to adopt an innovation” (Rogers, 2003, p. 177). There are two types of adoption: continued adoption and discontinuance. The former refers to further use of an innovation after adoption while the latter implies rejection of an innovation after its initial adoption (Rogers, 2003). Likewise, rejection is of two types - later adoption and continued rejection. The former infers future adoption of an innovation that was initially rejected, while the latter refers to persistent rejection (Rogers, 2003). Rogers also acknowledged active and passive rejection and described active rejection as a situation in which an individual has been thinking for a while about an innovation but later decides not to accept it. In passive rejection, an individual neither thinks of the innovation nor adopts it. This study suggests a fresh start from knowledge or awareness for any rejected innovation (Figure 3.9). Rejection could mean that the innovation needs to be refined by identifying ambiguities or complications and resolving them. This will improve such innovation and make it more valuable and effective.

KNOWLEDGE/ PERSUASION DECISION IMPLEMENTATION CONFIRMATION AWARENESS

Rejection

Adoption/ Acceptance

Figure 3.9: Modified innovation-decision process Source: Modified from Rogers (1995)

The decision to adopt an innovation will lead to the stage (implementation) where it will be used. At this stage, innovations will be used, tested, and checked for their effectiveness. However, Rogers (2003) revealed that uncertainty on the part of the users or societies could hinder successful implementation. Therefore, to reduce the degree of uncertainty, technical assistance may be required from innovation experts and others (Sahin, 2006). This leads to the confirmation stage, where individuals confirm their stance on an innovation. Rogers (2003, p. 189) asserted that decisions at this stage could be reversed if an individual is “exposed to conflicting messages about the innovation”. This suggests that more supportive messages are required from experts and others. However, Sahin (2006) stated that individual attitudes are

117

fundamental at this stage because they determine later adoption or discontinuance of the innovation.

The diffusion of innovation theory could be applied in any field and to any innovation, be it tangible or intangible. This theory applies to the development, implementation, and transition to a CE in the construction industry. Being a non-physical innovation, the innovation decision process could be followed in its adoption and, where necessary, additional stages may be added. This research builds on the DOI theory using the innovation decision process as a foundation for the development of a CE waste minimisation framework.

3.9 Summary The objective of this chapter was to establish the concept of the CE and its application as a possible approach to waste minimisation in the construction industry. The chapter began with a description of the origin of the CE concept to clearly articulate the chronological order and nomenclature of the CE. The common themes in the definitions of a CE are resource efficiency, waste and energy reduction. A review of the CE literature revealed several core principles – reduce, reuse, and recycle. The literature also provided insights into the characteristics of the CE. Its characteristics included designing out waste, building resilience through diversity, relying on energy from renewables, systems thinking, and thinking in cascades. Furthermore, the review revealed different schools of thoughts about the CE including C2C, biomimicry, industrial ecology, reverse logistics, and material passports. Many of these are sustainability concepts believed to be the roots of the CE. The reviewed approaches to the CE, which are product design, business models, enabling conditions, reverse networks, top-down and bottom- up approaches, and the tools and techniques, provide the impetus to transition to the CE. The review highlighted valuable insights into the practical application and appropriate policies and strategies for smooth transition and CE adoption across various economic sectors.

The CE was assessed to identify its benefits, drivers, challenges, and criticisms. The potential benefits of the CE cut across economic development, environmental reformation, and social advantages, while the drivers were categorised into policy and economic, health, environment, society, and product development. Similarly, the challenges were categorised as consumer related barriers, industry barriers (including those created by designers and producers) and government barriers. It was concluded that the main criticism of the CE is its partial exclusion of the social dimension of SD. A review of the environmental impacts of the CE identified the following: waste minimisation, resource efficiency, pollution reduction, improved eco-

118

efficiency, extension of lifecycle of landfill site, emissions reduction, energy efficiency, and reduced environmental poverty. The economic impacts identified include: job opportunities, material savings, economic gains, and cost savings to businesses, while the social impacts related to the sharing economy, collaboration and cooperation between consumers and producers, improved relationships between industrial sectors and local societies and networks for reuse and resource sharing.

The opportunities for the CE in the construction industry as reviewed in this chapter include product reuse, savings on waste management costs, and reduced energy input in producing new materials by applying the 3R principle. The approaches to implementing the CE in the construction industry were grouped in six categories: design, reuse and recycle, construction methods, business model, tools, and policies. In conclusion, the DOI theory was found appropriate to inform the development of a CE waste minimisation framework.

Having described the CE concept and its use in the construction industry, the next chapter details the process and procedure for data collection and analyses the development of a CE waste minimisation framework. The chapter outlines the paradigm, approach, methods, design and validity of the research, including reliability and generalisability.

119

CHAPTER FOUR RESEARCH METHODOLOGY 4.0 Overview Chapter one discussed the research problem, gaps, aim, objectives, scope and limitations. Chapter two reviewed the construction literature and SD concepts, including waste management, leading to the exploration of the CE concept as a waste minimisation method in chapter three. In addition, chapter three explored the CE’s principles, characteristics, and practical application in the construction industry, which suggest the type of data needed to accomplish the purpose of the study.

Chapter four provides detailed procedures for achieving the research objectives. The methodology is divided into four parts. Phase one covers the pragmatism paradigm, which is the philosophical assumption underpinning the study. A combination of research approaches – inductive and deductive, which aligns with the pragmatic paradigm, are described. To explore the minimisation of construction material waste, appropriate quantitative and qualitative methods were mixed. A concurrent triangulation design was adopted to integrate the quantitative and qualitative methods.

The second phase describes the quantitative method adopted. A cross-sectional survey was conducted to assess the types, causes, and effects of construction material waste, as well as waste minimisation techniques, strategies, and behaviour of building construction professionals. A validated questionnaire was used to elicit information from building construction professionals, including architects, builders, engineers, foremen, main contractors, project managers, quantity surveyors, and sub-contractors. Information collected included their awareness and attitudes to, and perceptions of, waste minimisation, as well as their approaches to waste minimisation and implementation methods. This was used to assess appropriate design, procurement, and construction approaches to waste minimisation and to identify the effective strategies.

Phase three describes the qualitative method, which employs field research including direct observation and semi-structured face-to-face interviews with architects, engineers, builders, project managers, quantity surveyors, foremen, main contractors and sub-contractors on ongoing construction project sites identified through purposive sampling. The interview collected information related to the causes, types, and effects of construction material waste while additional information on the type of waste were collected through direct observation.

120

Information on the awareness, attitudes, and perceptions of construction professionals, as well as waste minimisation strategies, were elicited. This information was analysed by identifying patterns that overtly answer each research questions.

The fourth phase describes the measure of consistency and accuracy of the instruments and data, which are known as reliability and validity. A research framework describing the procedure for reporting the results and data merging is presented. Figure 4.1 shows how the contents of this chapter relate and interact with each other, while Figure 4.2 highlights the sequence from the research problem to recommendations and conclusion. A full description of the four phases is detailed in subsequent sections.

Joint display Approach

Figure 4.1: Summary of the research design

121

Figure 4.2: Research sequence

Phase One

4.1 Research Paradigm Research paradigms include postpositivism, constructivism, participatory and pragmatism (Creswell and Plano Clark, 2017; 2011). For this investigation, the pragmatism paradigm is adopted, as it permits the researcher to explore different ways of investigating the phenomenon of construction waste minimisation. As the aim of this research is to develop a circular- economy-based construction waste minimisation framework for the Nigerian building construction industry, the pragmatism paradigm allows for practical solutions for the problem addressed in this project. Furthermore, since pragmatic approaches do not determine the choice of a paradigm, it is relevant to elicit information on the types and causes of material waste. Pragmatism has been argued as an appropriate paradigm for conducting research about behaviour (Brierley, 2017), hence its adoption in this study. As stated by Easterby-Smith, Thorpe and Jackson (2012), it enables awareness and attitudes to be quantified numerically. A pragmatic paradigm also accounts for the disparity between constructivism and postpositivism, proving robust results by combining insights and procedures from these two approaches (Johnson & Onwuegbuzie, 2004). According to Grbich (2012, p. 9) it emphasises “empirical knowledge, action, triangulation, and the changing interaction between the organism and its environments”.

122

The paradigm allows sourcing of appropriate data collection and analysis methods (Johnson & Onwuegbuzie, 2004; Creswell, 2003; Tashakkori & Teddlie, 1998;) to provide insights into the phenomenon under investigation. As a result, data collection methods and analyses adopted for this study have been decided without any philosophical constraints or loyalty to any alternative paradigm (Mackenzie & Knipe, 2006). They link the purpose and nature of the research questions, as suggested by Creswell (2003). In addition, the pragmatism paradigm is a well- established approach commonly used for mixed methods research (Creswell & Poth, 2017; Teddlie & Tashakkori, 2009; Hall, 2013; Creswell & Plano Clark, 2007) focusing on the research problem and its consequences (Creswell & Plano Clark, 2007; Miller, 2006; Tashakkori & Teddlie, 1998). It has been described as the “best paradigm” for mixed method research (Teddlie & Tashakkori, 2009, p. 99). Also, pragmatism does not assume the nature of knowledge, rather, it proffers solutions to problems (Yvonne Feilzer, 2010) by recognising the nature of reality as a measure to differentiate research approaches (Morgan, 2014). To achieve the research aim, appropriate research methods that answer the research questions were chosen, as suggested by Creswell and Plano Clark (2011) and Teddlie and Tashakkori (2009). The mixed methods combine both quantitative and qualitative methods in a single enquiry, with the former emphasising a “deductive, objective and generalisable approach” while the latter deals with the “inductive, subjective and context specific” (Brierley, 2017, p. 19).

The research objectives determined by the research questions and sub-questions were developed based on the pragmatic philosophical assumption. As revealed in Table 4.1, pragmatism paradigm influenced the decision to adopt mixed methods and descriptive research design.

Table 4.1: Logical relationship between research paradigm, method and design Positivism Interpretivism Pragmatism Critical realism Research Deductive Inductive Deductive and Deductive or Approach Inductive inductive Ontology Objective Subjective Objective or subjective Subjective- objective Axiology Value-free and etic Value-bond and Value-bond and etic- Value-laden and emic emic etic Epistemology Detached Transitional Detached and Transactional participatory participatory in predetermined sequence Methodology Quantitative Qualitative Qualitative and/or Qualitative or quantitative (Mixed or qualitative multi methods)

123

Positivism Interpretivism Pragmatism Critical realism Research Experimental (True Interactive Descriptive Action research design experimental, quasi (Ethnography, experimental and Phenomenology, Explanatory Ideology critique single subject) Case study, Grounded theory Exploratory Non-experimental and Critical (Descriptive, studies) comparative, Correlational, Survey Non-interactive and Ex-post facto) (Content analysis and historical analysis) Research Causal Descriptive Observational- Causal or question Relational and Observational- descriptive Relational Principle Uncover the universal Describe and Describe, explain and Co-creation of laws that governs explain social understand meanings, knowledge social events phenomena from values and beliefs of participant’s social phenomena from perspective participants and researchers’ perspective End result Universal In-depth In-depth explanation Critique and generalisation explanation transformation of Detailed context-based social structures Explanation Social generalisation reconstruction Social Prediction More than one reconstruction conclusion. Emancipation Social reconstruction Source: Adapted from Wilson (2014), Saunders, Lewis, & Thornhill (2009), Guba and Lincoln (2005)

4.2 Research Approach Aligned with the pragmatism paradigm, both inductive and deductive approaches to the research problem were adopted, as described by Bhattacherjee (2012). The inductive approach collects and analyses information related to the causes, types, and effects of construction material waste as well as information on NCI waste minimisation strategies. The data is collected to formulate a theory to explain and understand construction waste minimisation.

The deductive approach tests theories identified in the literature. These hypotheses and theories are detailed in chapters two and three. Specifically, the deductive approach tests the relationship between a company’s awareness, attitudes, and perceptions to waste minimisation. It also assesses the relationship between a company’s characteristics and approaches to waste minimisation.

124

Literature (Blackstone, 2012; Gray, 2013) shows that a combination of inductive and deductive approaches offers a full understanding of the phenomenon being studied. For this study, deductive and inductive approaches are combined to investigate theories and explain construction waste minimisation, as described by Wallace (1971), to account for strengths and weaknesses so that theory formation and empirical research can occur concurrently (Figure 4.). The purpose is to ensure that where findings from the deductive research are sparse, the inductive research provides supplementary explanations.

Figure 4.3: Logic of inductive and deductive reasoning Source: Bhattacherjee (2012)

4.3 Mixed Methods Mixed methods integrate both quantitative and qualitative data in an enquiry to enhance understanding of research problems and questions (Creswell & Plano Clark, 2011). Further, the mixed method approach ensures that one method complements or compensates for the other (Palinkas et al. 2011). A mixed method is the most suitable approach for this investigation because it aligns with the pragmatism paradigm. Previous studies (Creswell & Poth, 2017; Flick, Garms-Homolova, Herrmann, Kuck, & Röhnsch, 2012; Fielding, 2012) have shown that it produces results that are viable compared to single methods. A single method cannot provide satisfactory answers to the questions because of the complex nature of the research phenomenon, hence a mixed method is appropriate. To elicit rich data to answer research questions, quantitative and qualitative research methods were combined. Quantitatively, information on the causes, types, and effects of construction material waste were collected. Similarly, behaviours such as awareness, attitudes, and perceptions were investigated. In addition, waste minimisation strategies and implementation methods were obtained. The same set of information was collected qualitatively. The combining of both quantitative and qualitative research methods in an investigation is tantamount to theory development (i.e.

125 circular economy waste minimisation framework). This is the main aim of the study. This approach also enhanced triangulation between methods (Figure 4.).

Figure 4.4: Triangulation Source: Yeasmin and Rahman (2012, p. 156)

4.4 Triangulation Design In a mixed research method, integrating quantitative and qualitative research is critical. Methodological triangulation, which combines quantitative and qualitative methods, is adopted to ensure validation and credibility of the two methods. The process was guided by the concurrent triangulation design (Figure 4.) recommended by Creswell et al. (2003). Concurrently, with equal priority, quantitative and qualitative data were collected and analysed. The numerical information obtained via the quantitative method was adequately covered by detailed explanations provided by the qualitative method. Findings from both methods were integrated at the interpretation stage without any due consideration for specific theoretical perspectives. This methodological triangulation, which aligns with pragmatic research paradigms, indicates its appropriateness for this study.

Figure 4.5: Concurrent triangulation design Source: Creswell et al. (2003, p. 181)

126

Phase Two 4.5 Quantitative Phase Empirically, data were collected about construction material waste (types, causes, and disposal), and the attitudes of building construction firms in Lagos, as well as their current minimisation techniques. A survey method was adopted to investigate the relationship between respondents’ awareness, attitudes, and perceptions. Its purpose was to determine the characteristics of building construction firms, including ownership status, age, size, and area of specialisation. The methods adopted were questionnaires and interviews, as they allow for generalisability of opinions provided by a sample population (Creswell, 2014a; de Vaus, 2013). A structured questionnaire consisting of closed-ended questions was developed and administered. Similarly, semi-structured interviews were conducted face-to-face.

4.5.1 Unit of Analysis For this study, the analytical unit is a building construction firm consisting of multiple groups of professionals with common purpose. The organisational level was found appropriate since the study focuses on attributes relating to building construction firms. Owing to the fragmented character of the industry, embedded groups exist within the organisational level unit of analysis. These are the multiple groups that are represented in an organisation. For this study, they include building construction professionals such as architects, builders, engineers, project managers and quantity surveyors and they relate to the organisation as departments or divisions, not just as groups. The data obtained and analysed were from the multiple groups representing each construction firm.

4.5.2 Questionnaire Development A questionnaire survey was adopted as the quantitative research instrument. It consisted of closed-ended questions with answers including rating scale, multiple choice and rank order questions. Closed-ended questions were found appropriate for this study. In addition, they make statistical analysis straightforward since they require predetermined answers (Burns & Bush, 2006). Modes of administering questionnaires include mail, face-to-face, telephone, and internet/online (email and web-based). A mix of these modes has been recommended by Bryman (2015) to improve response rate. Online (email and web-based) and face-to-face approaches were combined due to their numerous advantages. Online approaches are preferred when the anonymity of respondents is important. Similarly, there is minimal interference from the researcher when using online approaches. Although face-to-face interactions are time consuming and expensive, they yield a good response and are useful for complex questions

127

(Frankfort-Nachmias & Nachmias, 1996). A web link generated from an online cloud-based software (www.surveymonkey.com) was emailed to potential respondents (see section 4.5.3) for further details about respondent selection and sampling). According to Ahmed et al. (2016), the online approach is cheap and saves time with data administration. To ensure credibility of the research results, a high response rate is desired. For this study, questionnaires were administered via the online survey (web link and associated email) and paper-based. Respondents were allowed to complete them on their own. For those administered online, two reminders were sent at regular interval to ensure prompt completion as suggested by Bhattacherjee (2012).

The questionnaire (see Appendix F) consisted of four sections. The first section included questions about the respondent’s background, their firm, and the extent of waste generated and disposed of by the firm. The second section explored the firm’s awareness and attitudes to, and perceptions of, the effects of construction waste as identified in literature. The third section requested respondent’s to detail their firm’s waste minimisation approaches and the firm’s 3Rs (reduce, reuse and recycle) approaches to waste minimisation. Variables for this section were adopted from the literature. The last section requested respondents’ opinions on policy and implementation methods for waste minimisation. Validated implementation methods were listed and respondents’ opinions on appropriate methods were requested. In addition, current waste minimisation strategies used globally were identified from literature and listed for respondents to decide on the extent to which they applied to the NCI. A detailed list of indicators and criteria used for the questionnaire is provided in Appendices B, C and D.

Saunders et al. (2007) reiterated that questionnaires need to be carefully designed to facilitate maximum response rates, validity and reliability of data. Precautions were taken to limit the number of variables and focus on the research questions (Black, 2001; Wright, Manigault, & Black, 2004). As stated earlier, closed-ended questions were found appropriate and adopted for the questionnaire. They were used to prevent excessive data generation, which could lead to complications during data reduction and analysis. The design was flexible, layout and format

were carefully considered, and questions were stated in simple language to avoid ambiguity. The questionnaire contained a total of 194 items (see Appendix F).

The variables (Appendix F) were ranked on a Likert scale. This is a form of interval scale with four, five, six or seven-point ratings (Saunders et al., 2007). According to Bernard (2011), the choice of a Likert scale hinges on the items being odd numbers (wherein a neutral midpoint is created) or even numbers (wherein the respondents need to take a stand). A five-point Likert

128

scale was adopted, where 1 = Strongly disagree/Never been used, 2 = Disagree/Rarely used, 3 = Neutral/Used in some projects, 4 = Agree/Used in most projects and 5 = Strongly agree/Used in all projects. Garland (1991) supports the use of a 5-point Likert scale for this type of study because it allows respondents to choose the option that expresses their opinions. It does not force respondents, and is commonly used to measure attitudes (Cohen, Manion, & Morrison, 2000).

4.5.3 Sampling This study was a cross-sectional study in which collection of data was extended for a short time. A simple random sampling of the population (i.e. building construction firms) was found suitable because it entailed analysing a segment of the population and providing information about the entire population (Creswell, 2007; Kumar, 2011). Also, it is commonly adopted when selecting a probability sample. To identify the sample size, a list of building construction firms in Lagos, Nigeria was obtained from Vconnect (an online register of companies in Nigeria – www.vconnect.com) due to the lack of a publicly available directory of construction firms and industry data, as confirmed by the country’s cooperate affairs commission (see Appendix E). In 2016, VConnect had 2684 building construction firms domiciled in Lagos. The formula developed by Cochran (1983, p.75) was used to identify an adequate sample:

2 no = Z pq …………………………………………………. …………………….Equation 1 e2 where,

no = sample size, Z2 = the abscissa of the normal curve that cuts off an area α at the tails (1.96) e = the desired level of precision p = the estimated proportion of an attribute that is present in the population q = 1-p

By using the Equation (1) above, Z = 1.96; e = 0.05 (i.e. confidence interval); p = 0.5 (i.e. 50% expected true proportion), and q = 1 - 0.5. The sample size obtained was 337. To justify this sample size, a statistical power analysis was conducted. Using Cohen’s (1988) criteria, this study adopted effect size of 0.2, which was deemed exceptionally small. The estimated sample size required with this effect size is approximately 263 with an alpha = .05 and power = 0.80.

129

Therefore, using a large sample size would generate higher power. Consequently, the proposed sample size of 337 will be more than adequate for the objectives of the study.

4.5.4 Pre-Testing To examine the clarity and feasibility of the questionnaire, a pilot survey was conducted. A sample of respondents was drawn from the same online register (VConnect) as the main survey. A total of 15 construction firms were contacted and 15 questionnaires were sent out. The required number of respondents for a pilot test remains unclear in the literature, however, a percentage of the total sample population is advised. Fink (2003) claimed that a minimum of 10 respondents is required and this further justified the number included in this study. Although these respondents were not included in the main survey, their responses and suggestions were used to refine the wording of the final questionnaire. Responses received from the pilot questionnaire were screened and inaccuracies relating to spelling errors, numbering mistakes, ambiguous questions, abbreviations, and inconsistency with ranking options were corrected.

4.5.5 Data Collection The sample for this survey was drawn from the online register of building construction firms in Lagos, Nigeria. The sample required for this study was 337 as calculated in section 4.5.3. To achieve that figure, 700 questionnaires were emailed (online survey) to respondents and 30 questionnaires were administered face-to-face (paper based). Overall, a total of 730 questionnaires were administered to building construction firms in Lagos. A consent form and information statement accompanied each questionnaire. As described in section 4.5.2, most of the questions asked respondents to indicate the extent of their agreement with statements or level of usage of strategies on a five-point Likert scale. Some other questions asked respondents to rank a series of alternatives.

To encourage a good response to the online survey, two basic steps were followed. Firstly, an email (see Appendix G) was sent to potential respondents with the web link to the main survey. The second step was a reminder email (see Appendix H) which was sent three weeks after the main survey. The online survey was opened from 10 October 2016 till 28 February 2017.

The face-to-face questionnaires were administered via two basic steps. The first involved hand delivery of the questionnaire to the respondents. The majority requested that the researcher wait for the completed questionnaire while others agreed on a date for collection. The second step involved the collection of completed questionnaires from respondents. With this process,

130 all questionnaires administered face-to-face were returned. They were entered manually into the online database where other responses were stored.

4.5.6 Margin of Error To determine the margin of error, a sample size and a desired confidence level are required. For a small margin of error, a large sample size is required to ensure that the result represents the entire population. According to Sutrisna (2004), any sample size exceeding the 30 (n > 30) threshold may be accepted as a large sample. Statistically, a large sample is also required for inferential statistics to draw inferences about the population.

The sample size of 337 required for this study was considered adequate, particularly for inferential statistics purposes. Based on the number of responses obtained, the margin of error was computed. Using equation 2, an estimate of 3% was obtained at 95% confidence level.

( ) MOE = ……………………………………………………Equation 2 ( ) /( ) �∗��∗ 1−�

� �−1 ∗ � �−� where, MOE = Margin of error z = 1.96 p = sample proportion n = sample size N = population size

The closer to zero the margin of error, the greater the confidence that the result represents the entire population. Therefore, there is a 95% probability that results obtained at 3% margin of error is appropriate for this study.

4.5.7 Quantitative Data Analysis Most questions in the questionnaire (Appendix F) measure the opinion of respondents on a five-point Likert scale. For example, respondents were requested to rate their level of agreement to the causes of material waste on a scale ranging from “Strongly disagree” to “Strongly agree”. This type of measurement scale followed the ordinal and nominal scale. Data distribution was assessed using Q-Q chart and demonstrated that the data were non-parametric. Therefore, non-parametric statistics were used for data analysis. Analysis of data using non- parametric statistics, such as descriptive statistics analysis, relative importance index analysis,

131

Kruskal-Wallis test, Friedman test, Kendall Coefficient of Concordance, Chi Square tests, tests for association, Spearman’s rank correlation, Factor analysis, and statistical significance was found appropriate.

4.5.7.1 Descriptive Statistics Analysis Descriptive statistical analyses adopted in this study are measure of frequency, mean, standard deviation, and percentiles. Measure of frequency was used to identify how often a response was given to a question. For example, it was used to determine the ownership status of building construction firms, age of organisations, size, a firm’s area of specialisation, and waste disposal methods. Mean identifies the average value of responses and was used to provide an overall description of those responses. For example, it was used to rank the types of material waste, and causes of material waste. Standard deviation was used in conjunction with the mean value to describe the level of dispersion of responses obtained. Percentile was used to report scores obtained for responses to questions. It provided the least, medium and most scores and was used for ranking of responses. Similar to the mean, percentile was used to rank the types of material waste, and causes of material waste. The results of data analyses were displayed graphically in the form of tables and bar charts.

4.5.7.2 Relative Importance Index Analysis In order to analyse variables on an ordinal scale, the relative importance index (RII) was employed. RII was used to rank variables in a group by calculating the summative weighting frequency scores of each variable. The formula in equation 3, where ‘w’ is the weight for the rating scale of one to five assigned by respondents, with one (strongly disagree) being the least and five (strongly agree) being the highest. As shown in equation 3, ‘A’ represents the highest weight (five) and ‘N’, the total number of responses.

RII = …………………………………………………………………… Equation 3 � For this ∑study,�∗� RII was used to rank the causes of material waste at design, procurement, and construction phases. In addition, design approaches, procurement approaches, construction approaches, 3R approaches, waste minimisation factors, waste minimisation strategies, and waste minimisation implementation methods were ranked using the RII analysis.

4.5.7.3 Kruskal-Wallis This test is a non-parametric test in which differences between three or more independent samples are determined. The Kruskal-Wallis test was used for this study to analyse statistically

132

significant differences in awareness, perceptions, and attitudes among respondents and company characteristics. It was also used to determine whether a company’s waste minimisation approaches were reliant on their characteristics. The Kruskal-Wallis test was adopted because it is suitable for ordinal data and could be used to compare two or more groups of equal or diverse sample sizes (Kruskal & Wallis, 1952).

4.5.7.3 Friedman Test The Friedman is a non-parametric approach that was conducted to test the significant difference between material waste types and material waste causes. In addition, the Friedman test examined the differences between waste minimisation implementation methods. This test was found appropriate for the study, having met all the required assumptions.

4.5.7.4 Chi-Square Test The chi-square test, a non-parametric test, was conducted to assess whether a relationship exists between two categorical variables. It was used to check for significant relationships between types and causes of material waste. Also, the Chi-square test was employed to identify significant associations among respondents’ awareness, attitudes, and perceptions to material waste and a company’s characteristics, as well as NBCFs’ waste minimisation strategies and a company’s characteristics.

4.5.7.5 Hypothesis Testing The null and alternate hypotheses were stated (see section 1.4), the criterion for decision (reject or accept) was the significance level (p-value ≤ 0.05). The null hypotheses were stated to predict relationships or significant differences between NBCFs’ awareness and a company’s characteristics; NBCFs’ perceptions and a company’s characteristics; and NBCFs’ attitudes and a company’s characteristics. In addition, null hypotheses were postulated to determine the significant difference between the NBCFs’ characteristics and waste minimisation approaches. The alternate hypotheses to evaluate the relationship between awareness and perceptions, awareness and attitudes, and perceptions and attitudes were also stated.

4.5.7.6 Spearman’s Rank Correlation This is a non-parametric test that is employed to assess the association level among two variables. The test was used to determine the relationship between respondents’ awareness and their attitude to waste. Likewise, it was used to test the nature and extent of association between awareness and perceptions as well as the relationship between attitudes to and perceptions of waste. The Spearman rho was also conducted to evaluate the strength of the relationship

133

between variables to determine whether it was statistically significant or not. The coefficient values ranging from -1 to +1 were used to indicate the strength of association, where -1 indicates a perfect negative association, a value of 0 indicates no association, and +1 indicates a positive association between the two variables. Since most data were collected on an ordinal scale, the Spearman rho was found appropriate for this study According to Schober, Boer, and Schwarte (2018), the Spearman rho is the suitable correlation analysis for variables measured on an ordinal scale.

4.5.7.7 Factor Analysis Factor analysis was performed using SPSS Statistics v24 to reduce the substantial number of variables to a smaller set that was easier to understand. For this study, factor analysis was used to re-categorise design approaches. A long list of procurement and construction approaches were also categorised into smaller sets that are self-explanatory. Several assumptions were made before factor analysis was performed to ensure that the p-values and confidence intervals are correct. These include adequate sample size, no multicollinearity between variables, linear relationship between variables, and inclusion of relevant variables into the analysis. The Kaiser-Meyer-Olkin (KMO) measure and Bartlett’s test of sphericity were conducted to ensure that the data met the aforementioned assumptions. Afterwards, principal component analysis (PCA) was employed to extract factors with a high eigenvalue. Varimax rotation, being the most common and default rotation method in SPSS, was used to help interpret the relationship between the observed variables and the latent factors. Exploratory factor analysis (EFA) was carried out to identify and group the design, procurement and construction approaches to material waste minimisation. From the analysis, the number of variables and models exploring the main concepts were generated.

4.5.7.8 Statistical Significance This was used to determine whether the research findings (relationships or differences) were reliable. The level of significance was determined by computing the p-value. For this study, p- value less than 0.05 was considered to be of significance, and vice versa.

Phase Three 4.6 Qualitative Phase Since this study investigates the status quo of waste minimisation by construction firms in Nigeria, field research including semi-structured interview and direct observation are appropriate for exploring the phenomenon. These are common methods for collecting

134

qualitative data (Bhattacherjee, 2012; King, 1994). Semi-structured interviews can be conducted face-to-face (personal interview), via telephone or by video call. For this study, face- to-face (personal) interviews were adopted as they provide opportunities to probe for rich data and to capture verbal and non-verbal input, including emotions and behaviours. With face-to- face interviews, problems commonly associated with telephone and video call interviews were mitigated (Rahman, 2015). The interviewer and interviewees were familiar with the language used and this facilitated easy communication during the interviews. Direct observation collects data through close visual inspection in a natural environment (Holmes, 2013). This method offers contextual data on people, situations, interactions and the surroundings (Drury, 1995). Direct observation can be conducted through field notes detailing behaviours, conversations or setting characteristics; structured protocols including checklist or rating scale; and photographs or video images. Photographs were adopted in this study as they provide visual evidence to support the volume of waste generated on construction sites.

4.6.1 Target Respondents Construction firms that specialise in building were targeted. Although a firm cannot be interviewed, the professionals and non-professionals it employs can be. They include architects, engineers (structural or civil), project managers, quantity surveyors, foremen, main contractors, and sub-contractors (see Table 4.2). These people are involved to some degree in waste generation and its minimisation and management on construction sites because their duties and responsibilities involve the design, procurement, construction, and management of buildings. They also constitute part of the stakeholders in construction. Project owners (i.e. clients) play important roles in waste generation and management because their decisions are vital to a project (Nurul Diyana & Abidin, 2013). However, project owners were not included because the study examines waste minimisation from the perspective of building construction firms. They were also excluded due to their unavailability, privacy issues, and security concerns. The choice of professionals and non-professionals was made to solicit their perceptions of the various approaches employed for waste minimisation from the design stage to the construction stage. In addition, the government agency responsible for waste management forms part of the target for this study because of their involvement with waste. The characteristics and identifiers of the construction professionals and non-professionals interviewed are described in Table 4.2.

135

Table 4.2: Target respondents, their characteristics and codes

Respondent Characteristics Code Architects The professionals concerned with the design, material A specification, and building aesthetics. Engineers The professionals concerned with the structural stability and E strength of buildings. Foremen The workers appointed to supervise other workers. F Main contractors Those responsible for the construction and completion of MC building projects, including the management of sub-contractors. Project managers Those responsible for the day-to-day activities on a building PM project from its inception to completion. Quantity The professionals responsible for cost control, estimation, QS surveyors procurement, and calculation of material costs and work done. Sub-contractors Those responsible for completing part or all of a project as SC allocated to them.

4.6.2 Structure of the Interview The conduct of the interviews was structured by an interview guide. The majority of the questions in the guide were derived from the literature and consist of the themes investigated in this study. As described in section 4.4, the concurrent triangulation design adopted for this research requires the simultaneous collection of both qualitative and quantitative data. Therefore, questions posed in the questionnaire were repeated in the interview. This aligns with validated approaches such the one proposed by Creswell et al. (2003), which states that both methods can be used to collect the same data with concurrent triangulation designs. The difference is that the questionnaire adopted closed-ended questions, while the interview adopted open-ended questions. The questionnaire comprised 28 main questions, which were compressed to 17 for the interview. It is important to note that the interviews also covered all of the questions used to measure the constructs in the questionnaire.

There are two parts to the interview guide (see Appendix I). The first part was the preliminary section consisting of an introduction and an explanation of the interview purpose. The researcher introduced himself, expounded upon the study’s objectives and the benefits its outcome would offer the firm and the industry as a whole. The second part consisted of the main survey questions, which were subdivided into five subsections (see Table 4.). The first subsection requested background information, followed by the second subsection, which sought in-depth information about the causes, types and disposal of material waste. The third subsection questioned interviewees about their perceptions of, and awareness and attitudes to waste, while the fourth explored the minimisation approaches currently adopted by the

136

interviewee’s employer (i.e. construction firm). The last subsection examined the interviewee’s opinions about appropriate implementation and managerial strategies for waste minimisation in Nigeria.

Table 4.3: Structure of the interview guide

Section Subsection Preliminary Introduction Purpose of the study Main Demographic data/Background information Causes, types and effects of material waste Awareness, attitudes and perceptions Material waste minimisation strategies Implementation and managerial strategies

4.6.3 Pilot Survey The pilot survey was aimed at pre-testing the instrument (semi-structured interview). Pre- testing was conducted with three construction professionals in Lagos who did not take part in the main study. These individuals were selected because they possessed all the required attributes for inclusion. There is no consensus as to whether the actual study should include respondents from pilot studies. The purpose of the pre-test was to detect problems or challenges with the instrument. It was conducted via telephone with respondents who were domiciled in Nigeria. There were two parts to the pre-test interviews. The first part included the actual questions while the second was a discussion about the interviewee’s understanding of the questions. This was to check whether or not the respondents has any difficulties in understanding what the questions were asking and whether they found any questions to be ambiguous. A digital audio recorder was used to record the pre-test interviews. The interview transcripts were reviewed and questions were revised by the researcher. Alterations were made to the content, wording, and format based on the suggestions and feedback received to ensure that all questions were unambiguous, unbiased and relevant to all interviewees. This was completed to ensure validity of the method as suggested by La Clara and Gemke (2013).

4.6.4 Sample Size The sample size (Malterud, Siersma, & Guassora, 2016) followed Robinson’s (2014) recommended four-point approach (Table 4.4) to qualitative sampling. To ensure that building construction firms were represented in this study, 10 ongoing building construction projects in Lagos were targeted.

137

Table 4.4: Approaches to qualitative sampling

Approach Description Step 1 Specify a sample universe Set up a sample universe, specifically through a set of criteria for inclusion and /or exclusion. Step 2 Determine the sample size Choose a sample size or range of sample sizes, taking into consideration what is ideal and practical. Step 3 Develop a strategy for sampling To specify categories of person to be included in the sample, select a purposive sampling strategy. Step 4 Source the sample Recruit respondents from the target population. Source: Adapted from Robinson (2014) The first approach was to define a sample universe in which the inclusion or exclusion criteria were determined. For a project to be included in the study, the project needed to be under construction and located in Lagos state, Nigeria. It was necessary for each interviewee to have at least three years’ experience in the construction industry and to work on the building construction project identified for the study. The second approach was to decide on the sample size. Seven respondents from each building construction project were identified (see Table 4.5). This number was considered to be realistic and practical. The ideal number of interviewees in a study remains unclear and may be “influenced by both theoretical and practical considerations” (Robinson, 2014 p. 29). Nevertheless, this issue remains a subject of debate. For example, Guest et al. (2006) quoted Bertaux’s (1981) suggestion of 15 as the smallest acceptable sample size. Crouch and McKenzie (2006) proposed a sample size of less than 20. Similarly, Adler and Adler (1987) suggested a sample size ranging from 12 to 60 while Ragin and Becker (1992) advised a sample size of 20 for Master’s thesis and 50 for a PhD dissertation. Several authors (Nelson, 2017; Saunders & Townsend, 2016; Morse, 2015; O’reilly & Parker, 2013; Walker 2012; Bowen, 2008) agreed that a researcher may stop interviews when no new information is provided by interviewees. The phenomenon is known as the saturation point. Whether the conventional sample size is 12, 15, 30, or 50, the sample size of 70 obtained for this study is deemed as appropriate. The sample size was mainly determined by the composition of construction professionals and non-professionals on building project sites. The recruitment of interviewees (see Table 4.2) on each project site was estimated to provide rich data from divergent views.

Table 4.5: Interview sample size

ID Project name Number of Interviewees

S1 DEM 7 S2 GE 7

138

ID Project name Number of Interviewees

S3 GT 7 S4 JQ 7 S5 OC 7 S6 RCG 7 S7 SE 7 S8 MH 7 S9 OS 7 S10 KT 7 Total 70

The third and fourth approach (Table 4.4) were to devise a sample strategy and source the sample. These approaches are interrelated and are mutually inclusive. The interviewees were recruited using purposive sampling, a non-probability sampling technique. Purposive sampling informs a decision on who can provide appropriate information to accomplish the study’s objectives (Matthews & Ross, 2014; Kumar, 2011). The interviewees were deemed to be suitable to provide detailed firsthand information about their company’s approaches to construction waste minimisation. Random purposive sampling based on the random selection of a sample in a purposefully selected target population (Tashakkori & Teddlie, 2003), was used to ensure the validity of the study.

4.6.5 Protocol for Interview An interview guide (see Table 4.) was developed due to the complex nature of construction waste minimisation. Interview questions were carefully drafted and pre-tested as described in section 4.6.3. The purpose of an interview protocol is to help the interviewer organise information in terms of questions and feedback. Being organised encompasses drafting questions, pilot testing and conducting the interview. The interviews were conducted face-to- face at the interviewee’s preferred venues and times. Most were conducted on construction sites. Overall, 65 interviews out of 70 proposed were conducted, representing a 92.8% response rate. This high rate has been described in the literature as one of the strengths of interview. Those who could not be interviewed were generally engaged with site activities and were unable to assist.

The interviews followed the structure described in Table 4.. In addition, the researcher probed and asked pertinent additional questions where appropriate. This aligns with Berg’s (2009) view of semi-structured interviews. The interviews spanned from 25 minutes to one hour. The variation was due to respondents’ busy schedules, time constraints and, probably, being

139

mindful of what to say. The average interview time was circa 41 minutes. All interviews were recorded via a digital audio recorder and with the signed consent of respondents. The researcher transcribed the recordings and read them for analysis. The method of analysis is described in section 4.6.7. A copy of the interview guide, information statement, and consent forms are presented in Appendix I, J (1&2), and K (1&2) respectively.

4.6.6 Project Characteristics and Response Rate Sections 4.5.1 and 4.6.4 discussed the target population and the required numbers respectively. The respondents were drawn from 10 ongoing building construction projects in seven locations across Lagos State, Nigeria. These projects ranged from residential to religious buildings. For each project, it was proposed that seven construction professionals be interviewed. Their selection was based on their involvement in waste minimisation and management. For ease of identification, a code was assigned to each building project, as shown in Table 4.6. In addition, the project descriptions or project names were abbreviated to ensure anonymity. Table 4.6 provides a summary of the building construction firms, their locations, projects and the number of interviewees who participated in this study.

Table 4.6: Project characteristics

Project characteristics Project Project Project type Project Firm Proposed Number of code name location Sizes Number of interviewees interviewees S1 DEM Religious Ikoyi Medium 7 7 S2 GE Residential Ajah Medium 7 6 S3 GT Commercial Victoria Large 7 6 Island S4 JQ Residential Ikoyi Small 7 7 S5 OC Commercial Lekki Small 7 6 S6 RCG Religious Yaba Medium 7 6 S7 SE Residential Ipaja Small 7 7 S8 MH Recreation/Entertain Ikeja Large 7 7 ment S9 OAS Mixed (Commercial Ikeja Large 7 6 and Recreation) 10 KT Commercial Ikoyi Large 7 7 Total 70 65 (92.8%)

4.6.7 Qualitative Data Analysis As stated in section 4.6, qualitative data were collected via semi-structured face-to-face interviews. Data were collected in audio form, transcribed, and analysed. Thematic analysis

140

was adopted to provide in-depth explanations, understanding and interpretation of construction waste minimisation. This aligns with the purpose of qualitative data analysis described by Flick (2013). Similarly, Moscarola (2002) identifies the purpose of textual data analysis to include analysing the text as a set of words to identify their relationships.

4.6.7.1 Thematic Analysis Using thematic analysis, the qualitative data were analysed. It is a type of analysis that categorises emerging themes (Fereday & Muir-Cochrane, 2006). Based on the characteristics of these data, they were coded and organised into categories. The title ‘thematic’ suggests an association with themes and was used to identify patterns within interview transcripts. Themes formed from the analysis were used to describe and explain construction waste minimisation. The analysis followed the procedure described by Woods (2011) and (Nicholls, 2009b) which is as follows:

i. Transcribing: Being the first stage of the analysis, interview recordings were transcribed verbatim into a word processing file (MS Word). Although the services of a transcribing agent or voice-recognition software may be used, the researcher painstakingly transcribed all the interviews to ensure accuracy given his familiarity with interviewees’ accents. ii. Initial reading: The transcripts were skim read several times to understand the ideas behind the raw data. An elementary coding was conducted with NVivo 11 pro, a computer assisted qualitative data analysis software (CAQDAS) application. NVivo 11 was used because it has the ability to manage large volumes of data (visual, audio, or text). In addition, nodes (i.e. pockets of ideas) were created while skimming the transcripts. iii. In-depth reading: Transcripts were perused thoroughly at this stage. Advanced coding based on the research objectives was initiated and, over time, additional themes relevant to waste minimisation approaches adopted by the firms emerged. These new themes were created as new nodes for each firm. All related nodes were organised into their matching themes. Thereafter, they were linked and explored to identify relationships between them. Tables were also drawn from interviewees’ characteristics to map out their background information. This was to examine the relationships between these characteristics. iv. Analytical Memos: In tandem with the analysis, memos were created. Memos in NVivo 11 pro record notes on issues, and comments and insights that emerged while

141

coding. These memos were used to keep records of the researcher’s reflections, ambiguous sections, analytical choices, inferences, iterative processes, and assumptions. These parameters form part of the notes that were used to articulate concise interpretations of the data. v. Code merger: The nodes created during the initial and in-depth reading were then merged into larger codes or conceptual units. Multiple nodes were created, indicating the richness of the data. These nodes were merged into parent nodes to create the main themes and sub-themes. vi. Integration: For each new category created in stage v, their properties and incidents are compared to integrate them into an organised entity. The integration involves a cross-case comparison of the new themes and an exploration of the relationships between them. As a result, some codes were reorganised into their most appropriate categories. This was achieved by identifying and merging codes explaining similar aspects. vii. Elimination of categories: At this stage, sub and main themes were examined for underlying uniformities. The number of themes was reduced to an adequate representation level by eliminating those with ambiguities. viii. Theory/Hypothesis development: Being the last stage of qualitative data analysis, theory was developed based on the preceding steps. The final themes identified aligned with the objectives of this study. The sub themes helped to provide explanations of the current construction waste minimisation approaches as well as the attitudes, awareness, and perceptions of the representatives of building construction firms in Nigeria. See chapter six for details of the analysis.

Stage Four 4.7 Validity, Reliability and Generalisability As described by Harper, Molenaar, and Cannon (2016), the degree of consistency of the metric results and the level of reproducibility using the same methodology are metric reliability. To ensure reliability and validity of the quantitative research instrument (questionnaire), pilot testing of the questionnaire was conducted (see section 4.5.4). Cronbach alpha is an internal consistency measure which checks similarity of responses to questions. Being the most widely used measure of reliability (Stangor, 1998; Bryman & Bell, 2007; Hair, Black, Grimm, & Yarnold, 2000), it was performed to ensure that the questionnaire items (data) were metrically

142

reliable and valid. Cronbach alpha was interpreted, as described by Hair, Black, Babin, Anderson, and Tatham (2006), as: α ≥ 0.9 = excellent; 0.9 > α ≥ 0.8 = good; 0.8 > α ≥ 0.7 = acceptable; 0.7 > α ≥ 0.6 = questionable; 0.6 > α ≥ 0.5 = poor; and 0.5 > α = unacceptable. The Cronbach alpha test value for this study was α = 0.83, demonstrating that the questionnaire items are consistent, reliable and valid (Ngacho & Das, 2014).

The issue of the validity, reliability and generalisability of qualitative research remains a subject of debate. To ensure validity of the qualitative strand of this study, several steps were taken. First, the research problem, design and interview questions were reviewed before they were used on the field. Further, the interview transcripts were rechecked with the interviewees

and were read six times to ensure they reflected what was actually said by the respondents. Reliability was enhanced by presenting a detailed description of the procedures followed in data collection and analysis to ensure that the findings could be easily traced to the data sources. All interviews were recorded to ensure a permanent record of what was said. This process aligns with Gray’s (2013) assertion that taped conversations present more reliable evidence than notes taken in the field. In addition, questions posed to interviewees were asked by the researcher, who has the same accent as the respondents and which arguably allowed them to express their opinions freely.

According to Lewis and Ritchie (2003), generalisation embodies two main issues, which are accuracy in interpreting a phenomenon and the actual sample representing a population. The quality of field work conducted, the painstaking analysis, interpretation as well as the sample size description in section 4.6.4 show that findings of the thesis are generalisable. Kalof, Dan, and Dietz (2008) suggest clear explanations of the sample selection criteria and clear depiction of a research site as ways to achieve generalisability of research findings. This study has, in section 4.6.4, described the sample selection and in sections 4.6.5 (protocol for interview), 4.6.7 (Qualitative data analysis), and 4.6.6, described the research site.

4.8 Data Merging Merging of data occurs in the interpretation and discussion sections (see chapter six) to investigate whether the quantitative and qualitative results converge or diverge. The ‘joint display’ method identified by Creswell and Plano Clark (2011) was adopted because it allows quantitative and qualitative results to be presented in a table or figure (Creswell & Plano Clark, 2011). The data are arrayed in themes, followed by explanations of the convergence or divergence. Although there is no hard and fast rule about the order of presentation (Creswell

143

& Plano Clark, 2011), quantitative data were presented first, followed by qualitative data. Furthermore, the merged data were then interpreted as described by Creswell and Plano Clark (2011), who suggest that a researcher must interpret collective results (quantitative and qualitative) to evaluate whether the research question has been answered. Figure 4.6 summarises the design that was adopted.

Joint display Approach

Figure 4.6: Convergent parallel design Source: Adapted from (Creswell, Plano Clark, Gutmann, & Hanson, 2003)

Congruent and divergent evidence (Lee & Greene, 2007) as well as consistencies or inconsistencies, conflicts, and contradictions were sought in the interpretation of the merged data (Slonim-Nevo & Nevo, 2009). Similarly, Creswell and Plano Clark (2011, p. 233) state that a mixed method researcher “should look for how the quantitative and qualitative databases tell different stories and to assess whether statistical results and the qualitative themes are more congruent than discrepant”. The majority of the findings in this research are congruent. As suggested by Bryman (2015), the discrepant findings form the basis for future research.

4.9 Ethics Considerations In all phases of field study, it is essential that ethical issues are considered (de Vaus, 2014). Several authors (Bouma, 2000; Guba & Lincoln, 1994; Saunders et al, 2007) also emphasise that caution regarding ethical and moral issues should be exercised in all forms of investigation. In addition, Saunders et al (2009) and Creswell (2013, 2014b) advise that possible ethical and moral issues, including confidentiality, privacy, anonymity, and exploitation of results, are carefully considered prior to data collection. Therefore, all parts of this investigation including the research topic, data collection, data analysis, and results were considered from ethical 144 perspectives. This is necessary to assure the quality of the research. Likewise, it is to protect survey participants and their organisations (Creswell, 2007) from repercussions arising from their statements (Robson & Robson, 2000). Hence, the responses were anonymised. In lieu of this, the research was subjected to The University of Newcastle Human Research Ethics Committee and approval (Ref: H-2016-0295) was obtained in September 2016.

4.10 Bias Bias is described as a type of systematic error that influences a research and manipulates the methodology and processes (Sica, 2006). It is any tendency or departure from the reality that leads to false findings (Simundić, 2013). Though eliminating bias in a research may be difficult, minimising it is essential to ensure clarity and appropriate interpretation and use of data. Bias in research cut across processes and levels including research design, data collection, data analysis and validity and reliability of results as well as participants’ selection process, sample size and interpretation of results (Smith & Noble, 2014). Table 4.7 describes potential biases in this study and the strategies that have been employed to minimise them.

Table 4.7: Potential bias and minimisation strategies

Potential bias Minimisation strategies

Research design To address the study aim, the rationale for and the selection of suitable research design was clearly expressed. Selection/participant Bias was reduced through random selection of participants in the quantitative study while random purposeful sampling was used in the qualitative study. Data collection and A well-designed research protocol was introduced for the quantitative analysis study clearly highlighting data collection and analysis. As for the qualitative study, the methodological approach showed rigour, openness, relevance and congruence. By validating responses, comparing accounts across respondents and triangulation, bias was reduced. A pilot study was conducted to reduce bias. Data interpretation Appropriate statistical tests were employed. The results were properly presented. The data was only interpreted if the perceived relationship was statistically significant.

145

4.11 Summary Table 4.8 provides a brief description of the research tools and procedures adopted in the study. It also justifies the choices made in the research design and process.

Table 4.8: Summary of the research methodology process

Research Selected research tools Reasons for choice Process and procedures

Research Pragmatic Philosophy: It The causes, types, and effects of construction Paradigm emphasises what best suits material wastes, behaviours of construction firms, the research problem and it as well as the status quo of waste minimisation by involves collecting and building construction firms are best understood analysing both quantitative from different theoretical positions, and qualitative data. methodologies, methods and techniques.

Research Deductive and Inductive In this study, both deductive and inductive Approach reasoning: Deductive reasoning were merged to explain and proffer reasoning develops strategies solutions on how construction material wastes can to test a theory while be minimised by the Nigerian building inductive reasoning develops construction industry. a theory from the data collected.

Research Multiple research designs: Multiple research design was employed to explore Design Literature review, survey and literature, obtain general perspectives, and x-ray interviews. issues and provide deeper insights, especially on how to minimise construction material wastes.

Research Mixed research methodology A concurrent triangulation design was employed Methodology to simultaneously collect and analyse both quantitative and qualitative data.

Time Horizon Cross-sectional time horizon The cross-sectional time horizon was adopted because it was deemed appropriate for this type of study.

Research Questionnaire and Semi- The questionnaire uses closed-ended questions to Method/s of structured interviews gather quantitative data from the NBCFs, while Data the interview uses semi-structured open-ended Collection questions to explore respondents’ views. Both questionnaire and interview were adopted in this study for the sake of triangulation and to provide additional details where there were not enough. For example, the interviews explained the reasons for choices made by respondents in the questionnaire.

Unit of Building construction firms This research analysed organisations/firms’ Analysis represented by their behaviours and approaches to construction waste employees minimisation. However, the responses of employees who participated in the research on behalf of their firms were analysed and taken as representative of the organisations’ responses.

146

Research Selected research tools Reasons for choice Process and procedures Sampling Multiple sampling For the quantitative strand of this study, simple Technique techniques: Simple random random sampling was adopted to select the (quantitative) and purposive sample from the population, while purposive sampling (qualitative) sampling was used for the qualitative strand.

Method of Data Statistical techniques and For qualitative data, both descriptive and Analysis thematic analysis inferential statistics such as factor analysis, relative importance index, and Spearman’s rho were applied, while the qualitative investigation was analysed using thematic analysis.

Ethics Human Research Ethics The human research ethics application was Approval Committee (HREC), approved by HREC, University of Newcastle, University of Newcastle before data collection. This was completed to Australia ensure that the study meets the statutory and research integrity obligations of the university (see Appendix M for details).

Source: Adapted from (Ahmed et al., 2016; Olanipekun, 2017) for this study

The next chapter provides details of the quantitative and qualitative data analyses and results obtained. The chapter also describes the sample characteristics, response rate and summary of results.

147

CHAPTER FIVE INTEGRATED DATA ANALYSIS AND FINDINGS 5.0 Overview Within chapter one, the research problem, gaps, aim and objectives were described. In chapters two and three respectively, a review of construction waste management and the concept of circular economy was conducted. Chapter four described the research methodology in which online and face-to-face questionnaires were administered for quantitative data collection. Simultaneously, semi-structured face-to-face interviews were conducted to obtain qualitative data. This aligns with the concurrent triangulation design for data collection described in section 4.4. Chapter five describes the results of the quantitative and qualitative data collected.

The results are presented in two sections. Section 5.1 describes quantitative data results and focuses on sample characteristics, results of the relative importance index analysis, correlation matrix, and factor analyses. It also details the results of Kendall’s coefficient of concordance and a Friedman test used to identify the level of agreement between respondents. The test results of the hypotheses developed to answer some of the research questions are presented. Section 5.1 ends with summaries of the quantitative data results.

Section 5.2 discusses the qualitative data. It starts by defining the sample characteristics, response rate and method of analysis. Furthermore, it uncovers the phenomena relating to the research questions by identifying patterns and classifying them into themes. Key statements and phrases pertaining to relevant facts or opinions in support of or in contrast to the research objectives and questions are provided. The section concludes with summaries of the findings.

Each section presents findings from data analysis, while the research questions guide the presentation of results. Figure 5.1 shows an outline of this chapter. Overall, it serves as a springboard for the discussion section (chapter six) leading to the development of a circular economy waste minimisation framework.

148

Overview

Sample Characteristics

Results/Responses

Summary Figure 5.1: Outline of chapter five

5.1 Quantitative Results The sample characteristics were described based on the number of responses obtained from the survey. This provided descriptive data relating to the respondents’ organisations. The data were analysed to provide a platform for comparing the findings across respondent and organisation data. The former includes current position, level of education, and years of experience while the latter consists of organisational structure, age, area of specialisation, and annual turnover. These responses were analysed using measures of frequency and percentages.

5.1.1 Response Rate Response rate literally means the number of individuals who actually completed and returned the questionnaire (American Association for Public Opinion Research Standards Committee, 2010). Out of the 730 questionnaires distributed online and face-to-face, 464 were returned, which represents 63.6%. However, only 243 out of the 464 returned questionnaires were completed in full. The overall response rate of 33.3% was therefore achieved. Table 5.1 presents a summary of the responses. An overall response rate of 33.3% is adequate compared to previous studies (Fahmy, Hassan, & Bassioni, 2014; Tam, 2008a). Such a response rate was reported as a common occurrence in the construction management domain (Takim, Akintoye, & Kelly, 2004; Dulaimi, Ling, & Bajracharya, 2003; Hong, 2002; Akintoye, 2000; Chinyio & Olomolaiye, 1999).

149

Table 5.1: Main survey response rate

Survey Category No. of Questionnaire Percentage Administered 730 Web-based 700 95.9 Face-to-face 30 4.1 (completed) Response 464 Uncompleted 221 30.3 Completed 243 33.3

5.1.2 Interpretation of Quantitative Results For ease of interpreting the results, Table 5.2 indicates the terms used to describe the percentage ranges of responses obtained where applicable.

Table 5.2: Terms used to describe percentage ranges

Range Meaning 100% All ≥ 80% < 100% Most ≥ 66.7% < 80% Majority > 50% < 66.7% More than half 50% Half > 33.3% < 50% Less than half ≤ 33.3% Minority Source: Adapted from (Emuze, 2011) 5.1.2.1 Respondent Data Table 5.3 shows the characteristics and distribution patterns of respondents in relation to their current position, level of education and years of experience. As illustrated in the table, less than half of the respondents are architects (36.2%), while quantity surveyors (21.4%), project managers (16.4%), engineers (10.3%), chief executive officers (5.8%), builders (4.5%), managers (2.9%), contract or quality managers (0.8%) and technicians (0.8%) are minorities. Other minority positions not listed in the questionnaire are cost managers (0.4%) and urban planners (0.4%). Construction professionals were well represented and provided a wide variety of opinions and views on waste minimisation methods.

In addition, Table 5.3 illustrates that respondents had various educational qualifications. Almost half (49.4%) had completed Masters’ degrees in relevant fields. The minority had completed Bachelor’s degrees (32.1%), Higher National Diplomas (12.3%), and Postgraduate Diplomas (4.1%), while only three respondents held a PhD and two respondents an Ordinary National Diploma, thereby representing 1.2% and 0.8% respectively. The varying educational levels provide an exploration of waste minimisation through different lenses.

150

Respondents’ years of experience are shown in Table 5.3. Less than half (45.7%) have between six and ten years’ of experience. The minority of the population have experience ranging from three to five years, 11 to 15 years, 16 to 20 years, and above 21 years. A minimum of three years’ construction experience was required for participation in this study. However, only 73 out of 243 respondents had three to five years’ experience, which implies that the remaining 170 respondents have more than five years’ construction experience. Therefore, all 243 respondents met the inclusion criteria for this study.

151

Table 5.3: Respondents’ characteristics

Characteristics Urban Chief Manager Project Architect Engineer Contract QS Builder Technician Total Years of planner Ex. Manager /Quality Experience Officer Manager 3-5 years 1 3 1 6 32 8 0 20 3 0 73 6-10 years 0 6 3 19 44 10 1 19 7 1 111 11-15 years 0 2 2 7 11 4 0 9 1 0 36 16-20 years 0 0 1 5 1 2 0 2 0 0 11 Above 21 years 0 3 0 3 0 1 1 3 0 1 12

Total 1 14 7 40 88 25 2 53 11 2 243 Education National 0 0 0 0 1 0 0 0 0 1 2 Diploma (ND) Higher 0 0 0 4 15 4 0 7 0 0 30 National Diploma Postgraduate 0 2 0 1 4 0 0 1 1 1 10 Diploma Bachelor 1 4 1 12 17 10 0 25 8 0 78 Masters 0 8 6 23 49 11 2 19 2 0 120 Doctor of 0 0 0 0 2 0 0 1 0 0 3 Philosophy (PhD) Total 1 14 7 40 88 25 2 53 11 2 243

152

5.1.2.2 Organisational Data First, respondents were asked to indicate their organisation’s ownership status, and the results show that more than half (66.3%) of the organisations surveyed were privately owned or owned by an individual (sole proprietorship), while 15.6% were owned by two or more people (partnership). Public limited companies (PLC) accounted for 10.7%, whereas Government established organisations represented 7.4%. A study conducted in Nigeria by Kolo (2015) revealed a similar situation, whereby 88.5% of the study population were privately owned construction firms.

Second, results about the longevity of construction firms show that 26.3% were above 21 years, 14% were within 16 to 20 years, 16% were within 11 to 15 years, 24% were between six to ten years, while 19.7% were between one to five years. In addition, respondents were asked to indicate the annual turnover of their organisation, and the results show that almost half (47%) of those surveyed were small scale, 24.7% were medium scale firms while 28.3% were large firms (see Table 5.4).

Table 5.4: Organisations’ characteristics

Characteristics Privately Partnership Government- Public Total owned owned Limited company Ownership status 161 38 18 26 243 Age of organisation 1-5 years 36 10 0 2 48 6-10 years 44 10 0 4 58 11-15 years 27 6 1 5 39 16-20 years 21 5 6 2 34 Above 21 years 33 7 11 13 64 Total 161 38 18 26 243 Organisation Turn over (Size) Up to N50million (Small scale) 83 18 5 8 114 N51million – N500million 38 9 5 8 60 (Medium scale) Above N501million (Large 40 11 8 10 69 scale) Total 161 38 18 26 243 Area of project specialisation New build 139 33 15 21 208 Maintenance/repair 12 2 1 2 17 Renovation 8 3 2 1 14 Demolition/deconstruction 2 0 0 2 4 Total 161 38 18 26 243

153

Third, respondents were asked to indicate their organisation’s area of specialisation. The results show that the main activity for most (80.2%) construction firms in Nigeria is new build. Other activities, such as maintenance/repair, renovation and demolition/deconstruction, were responsible for 4.1%, 3.3% and 0.8% respectively. Other types of activity included real estate, consultancy, and a combination of new build, maintenance, and renovation, which represents 11.5%. Responses of the NBCFs to construction material waste minimisation are presented in the following sections.

5.1.3 Quantitative Responses RQ1. What are the types, causes, and disposal methods of material waste in the Nigerian building construction industry?

5.1.3.1 Types of Material Waste The different types of construction material waste identified were ranked into six. Using the rank order of one to six, “most” (= 1) and “least” (= 6), respondents were asked to rank the type of material waste produced in their main construction activity. Table 5.5 shows that the ‘concrete, ceramics and stone’ group was ranked most, while the ‘plastic and rubber’ group was the least. Other types of material and how they were ranked are also shown in Table 5.5. The Friedman test was conducted to examine the differences between groups of materials.

Table 5.5: Types of material waste generated by the NBCFs

Types of material waste Mean Standard Percentiles Rank Deviation 25th 50th (Median) 75th Concrete, ceramics and 2.85 1.70484 1.000 3.000 4.000 1 stone Timber and timber 3.03 1.44848 2.000 3.000 4.000 2 products Bricks and blocks 3.03 1.71013 2.000 3.000 4.000 3 Metal products (e.g. 3.60 1.23996 3.000 4.000 4.000 4 reinforcement bars, aluminium, steel etc.) Glass 4.19 1.83927 3.000 5.000 6.000 5 Plastic and rubber 4.30 1.65478 3.000 5.000 6.000 6

Table 5.6 provides the test results, which shows a statistically significant difference between the different groups of material waste generated, χ2 (5) = 137.215, p ≤ 0.001. To determine where the difference actually occurred, Wilcoxon signed-rank tests with Bonferroni correction were conducted, resulting in p < 0.003. The median for each group is shown in Table 5.5. There was a statistically significant difference in almost all the groups except the ‘concrete, ceramics

154

and stone’ group and ‘timber and timber products’ group (Z = -1.204, p = 0.229); ‘concrete, ceramics and stone’ group and ‘bricks and blocks’ group (Z = -1.409, p = 0.159); ‘plastic and rubber’ group and ‘glass’ (Z = -1.007, p = 0.314); and ‘bricks and blocks’ group and ‘timber and timber products’ group (Z = -0.297, p = 0.767).

Table 5.6: Friedman test statistics for material waste

Concrete, Timber Glass Metal Plastic Bricks Friedman Test Statistics Ceramics products Products and and N χ2 df Asymp. & Stone Rubber Blocks Sig. Mean 2.85 3.03 4.19 3.60 4.30 3.03 243 137.215 5 0.000 Rank

5.1.3.2 Causes of Material Waste To understand the causes of material waste, it is important to investigate the different phases of construction (design, procurement and construction). The causes of waste in these phases were listed in the questionnaire (Appendix F). Respondents rated their level of agreement to the causes on a five-point Likert scale, from ‘strongly disagree’ to ‘strongly agree’. The results, as presented in Tables 5.7, 5.8, and 5.9, show that the most highly ranked design cause of material waste is design changes (RII = 0.844), while the least ranked is errors in contractual documents (RII = 0.664).

Table 5.7: Design causes of material waste Causes at design phase SD D N A SA W RII Rank Design changes 4 4 14 127 92 1022 0.844 1 Poor coordination and 4 15 19 147 57 964 0.797 2 communication between design team members Unclear/unsuitable specification 2 20 37 134 50 939 0.773 3 Lack of attention/knowledge 6 20 24 149 43 929 0.768 4 about dimensional coordination of material Designer’s inexperience in 4 26 32 130 50 922 0.762 5 method and sequence of construction Selection of low-quality 2 28 39 119 54 921 0.761 6 products Designer’s unfamiliarity with 3 20 38 145 36 917 0.757 7 alternative products Complexity of drawing details 10 52 55 99 26 805 0.665 8 Errors in contract documents 10 59 43 103 27 804 0.664 9

155

As for the procurement phase, substandard material is the highest ranked (RII = 0.777), closely followed by manufacturing defects or defective materials (RII = 0.773), while the least ranked was the lack of opportunities to order small quantities of materials (RII = 0.688). Quality of supervision (RII = 0.859), unconcerned attitude of project teams and labourers (RII = 0.835), and lack of on-site waste management plans (RII = 0.828) were ranked 1st, 2nd, and 3rd respectively during the actual construction phase. The least ranked causes were equipment malfunction (RII = 0.746), improper site layout (RII = 0.741), and accidents (RII = 0.734).

Table 5.8: Causes of material waste at the procurement phase

Causes at procurement phase SD D N A SA W RII Rank Substandard materials 4 23 34 116 65 941 0.777 1 Manufacturing defects or defective 1 16 35 153 37 935 0.773 2 materials Non-compliance with specification 4 26 37 135 40 907 0.749 3 Ordering errors (too much or too little) 5 26 43 130 38 896 0.740 4 Supplier’s errors 5 35 38 122 41 882 0.732 5 Bulk delivery (storage of materials 5 32 41 136 28 876 0.724 6 delivered in bulk) Lack of opportunities to order small 6 43 53 120 21 836 0.688 7 quantities

Table 5.9: Causes of material waste at the construction phase

Causes at construction phase SD D N A SA W RII Rank Quality of supervision 0 2 19 126 94 1035 0.859 1 Unconcerned attitude of project team 0 8 20 137 78 1014 0.835 2 and labourers Lack of on-site waste management 2 8 20 136 77 1007 0.828 3 plans Off-cuts from materials 2 7 27 136 71 996 0.819 4 Errors by tradespersons or labourers 2 13 19 146 63 984 0.809 5 Poor material storage 1 5 35 135 64 976 0.807 6 Waste from application processes (e.g. 1 11 19 151 57 969 0.811 7 plastering) On-site material controls 0 9 33 156 44 961 0.794 8 Ineffective communication 1 16 29 149 48 956 0.786 9 Required quantity differs from quantity 5 13 39 133 52 940 0.776 10 needed Use of incorrect material, thus 1 23 25 149 43 933 0.774 11 requiring replacement Equipment malfunction 3 16 51 146 27 907 0.746 12 Improper site layout 3 28 43 133 36 900 0.741 13 Accidents 1 17 65 136 22 884 0.734 14

156

To determine the phase generating the most waste, the average RII of each phase was calculated. The results show that the construction phase generated the most (RII = 0.794) waste, followed by the design phase (RII = 0.754), while the procurement phase generated the least (RII = 0.740). With all the causes of material waste collated, the quality of supervision was the highest ranked (1st), while errors in contract documentation was the least ranked (30th) (see Appendix N).

5.1.3.3 Method of Material Waste Disposal This study further examined methods adopted by the NBCFs for waste disposal. Disposal methods identified from the literature included open dumping, recycling, landfilling, composting, incineration, onsite dig and bury, reuse as backfill, and burning. Respondents were asked to identify the predominant method that applied to them. Descriptive statistics showing the resulting frequencies are presented in Table 5.10. A total of 23.5% of respondents identified ‘landfilling’ as their main method of waste disposal. Other disposal methods include ‘recycling’ (21.8%), ‘reuse as backfill’ (22.2%) and ‘open dumping’ (17.7%). While none of the respondents indicated ‘composting’, 2.9% specified ‘burning’ as their waste disposal method.

Table 5.10: Method of material waste disposal

Disposal Methods Frequency Open dumping 43 Recycling 53 Landfilling 57 Composting 0 Incineration 18 Reuse as backfill 54 Onsite dig and bury 11 Burning 7 Total 243

157

RQ2. What are the attitudes, awareness, and perceptions about construction waste minimisation by Nigerian building construction firms? 5.1.3.4 Awareness of the Effects of Material Wastages Table 5.11 indicates respondents’ awareness of the effects of material wastage. Respondents were requested to state their agreement level to a set of statements describing their awareness. This was assessed on a five-point Likert scale rating of ‘strongly disagree’ to ‘strongly agree’. Noticeably, respondents in general were aware of the effects of construction material waste. The results presented in Table 5.11 suggest that 28.4% strongly agreed that ‘construction waste is harmful to human health and environment’; while 2.5% disagreed. Interestingly, 19.8% of respondents strongly agreed that ‘waste of materials is avoidable’ while 28.4% disagreed. Notably, the results confirm the low rate of construction waste recycling. This was attested to by 47.7% and 37.9% of the respondents who agreed and strongly agreed respectively to the statement – ‘recycling rate of construction waste is low’.

The RII value of respondents’ awareness that ‘organised construction waste sorting will increase materials re-use’ was 0.868 and ranked 1st, while their awareness that ‘waste of material is avoidable’ (RII = 0.657) was ranked last.

Table 5.11: Relative importance index of NBCFs’ awareness

Awareness SD D N A SA W RII Rank An organised construction waste 5 4 3 121 109 1051 0.868 1 sorting method will increase materials re-use Recycling rate of construction waste is 7 12 14 116 92 997 0.827 2 low Construction waste is harmful to 6 17 40 111 69 949 0.781 3 human health and the environment Reusable containers/bags reduce 2 13 38 139 46 928 0.779 4 materials packaging waste Waste of materials is avoidable 19 69 26 80 48 795 0.657 5

5.1.3.5 Attitude of the NBCFs to Material Waste Minimisation Respondents were asked to respond to a list of statements about their attitudes to material waste minimisation. These were assessed on a five-point Likert scale, from ‘strongly disagree’ to ‘strongly agree’. As shown in Table 5.12, the respondents had a positive attitude to waste minimisation approaches. The findings reveal that 25.1% of respondents strongly agreed that they found it hard to change existing work practices, while 38.3% disagreed. Similarly, 40.3% disagreed that the cost of waste does not have much effect on the project, while 11.9% agreed.

158

On the other hand, 60.1% showed a positive attitude to material waste minimisation by interacting closely with their construction team. More than half (61.3%) of the respondents also advised their clients about the potential for waste reduction.

Overall, ranking respondents’ attitudes to material waste minimisation was assessed using the RII analysis. The statement, ‘I think cost of construction waste does not have much effect on the project’ was the least (RII 0.407), while ‘I see construction waste minimisation as important as other functions of construction management’ was rated first, with RII = 0.864 (see Table 5.12)

Table 5.12: Relative importance index of NBCFs’ attitude

Attitude SD D N A SA W RII Rank I see construction waste minimisation 2 4 12 121 104 1050 0.864 1 as important as other functions of construction management I interact closely with my construction 1 8 26 146 62 989 0.814 2 team to avoid material waste I advise clients where there is potential 0 9 28 149 57 983 0.809 3 for waste reduction I find it hard to change existing work 16 93 65 61 8 681 0.560 4 practices I think cost of waste does not have 87 98 20 29 6 489 0.407 5 much effect on the project

5.1.3.6 Perceptions of the NBCFs on Material Waste The study further examined the perception of the NBCFs on material waste based on a list of statements. The results shown in Table 5.13 reveal that 36.6% of respondents agreed that they perceived ‘the value of recycled or re-used construction materials is minimal,’ while 30% disagreed. Further, 54.3% of respondents agreed that ‘waste is an inevitable by-product on construction projects,’ whereas only 7.8% disagreed. More than half (51.0%) of respondents agreed with the perception that ‘waste generation is often the result of bad planning and management,’ while 3.7% disagreed.

The result of the RII indicate that the respondents’ perception that ‘through waste management, construction site employees can contribute significantly to protecting the environment’ was ranked first (RII = 0.845). Conversely, the perception that ‘the benefits of recycling construction waste are not worth the time required to sort waste materials for recycling’ was ranked least (RII = 0.488).

159

Table 5.13: Relative importance index of NBCFs’ perception

Perception SD D N A SA W RII Rank Through waste management, 1 9 5 147 81 1027 0.845 1 construction site employees can contribute significantly to protecting the environment Waste is an inevitable by- 7 19 28 132 57 942 0.775 2 product on construction projects Waste generation is often the 14 29 21 124 54 901 0.745 3 result of bad planning and management The value of recycled or re- 20 73 52 89 9 723 0.595 4 used construction materials is minimal The benefits of recycling 44 96 62 34 7 593 0.488 5 construction waste are not worth the time required to sort waste materials for recycling

5.1.3.7 Hypothesis Testing – Company Characteristics, Awareness, Perceptions, and Attitudes The awareness, perceptions and attitudes of the NBCFs were tested using the Kruskal-Wallis test. This was to ascertain the significant differences between the NBCFs’ awareness, perceptions, attitudes and organisational characteristics. The postulated null hypotheses were tested and the results are presented below.

5.1.3.7.1 NBCFs’ awareness and company size

Null Hypothesis H01 – “There is no statistically significant difference in the NBCFs’ awareness of material wastes based on company’s size”.

A Kruskal-Wallis H test showed that there was no statistically significant difference between NBCFs’ awareness of material wastes and company’s size, χ2 (2) = 1.848, p = 0.397. The mean rank was 128.48, 119.40, and 116.16 for small, medium and large scale companies respectively.

5.1.3.7.2 NBCFs’ awareness and company ownership status

Null Hypothesis H02 – “There is no significant difference in the NBCFs’ awareness of material wastes based on company’s ownership status”.

160

The result of the Kruskal-Wallis H test, χ2 (3) = 6.282, p = 0.099, with a mean rank of 127.90, 106.05, 134.64, and 100.04 for privately owned, partnership, government-owned, and public limited companies, respectively, indicates that there is no significant difference between NBCFs’ awareness of material wastes and a company’s ownership status.

5.1.3.7.3 NBCFs’ awareness and company’s main construction activity

Null Hypothesis H03 – “There is no significant difference in the NBCFs’ awareness of material wastes based on company’s main construction activity”.

The result of the Kruskal-Wallis H test suggests no statistically significant difference between NBCFs’ awareness of material wastes and a company’s main construction activity, χ2 (3) = 5.942, p = 0.114, with a mean rank company’s main construction activity of 119.72 for new build, 154.09 for maintenance/repair, 130.75 for renovation and 73.63 for construction/deconstruction.

5.1.3.7.4 NBCFs’ attitude and company size

Null Hypothesis H04 – “There is no statistically significant difference in the NBCFs’ attitude to material wastes based on company’s size”.

A Kruskal-Wallis test result, χ2 (2) = 2.247, p = 0.325, with a mean rank of 129.06, 116.72, and 114.93 for small, large, and medium scale companies, respectively, indicates no significant difference between the NBCFs’ attitudes to material waste and company size.

5.1.3.7.5 NBCFs’ attitude and company ownership status

Null Hypothesis H05 – “There is no significant difference in the NBCFs’ attitude to material wastes based on company’s ownership status”.

A Kruskal-Wallis H test indicated no significant difference between NBCFs’ attitudes to material wastes and company ownership status, χ2 (3) = 6.101, p = 0.107. The mean rank was 125.05, 111.62, 147.61, and 100.58 for privately owned, partnership, government-owned, and public limited companies, respectively.

5.1.3.7.6 NBCFs’ attitude and company’s main construction activity

Null Hypothesis H06 – “There is no significant difference in the NBCFs’ attitude to material wastes based on a company’s main construction activity”.

161

The result of the Kruskal-Wallis H test, χ2 (3) = 1.591, p = 0.661, with a mean rank of 124.23, 111.76, 107.39, and 100.50 for new build, maintenance/repair, renovation, and demolition/deconstruction activities, respectively, shows no significant difference between the NBCFs’ attitudes to material waste and the company’s main construction activity.

5.1.3.7.7 NBCFs’ perception and company size

Null Hypothesis H07 – “There is no statistically significant difference in the NBCFs’ perception of material wastes based on company’s size”.

A Kruskal-Wallis H test showed that there was no statistically significant difference between the NBCFs’ perception of material wastes and a company’s size, χ2 (2) = 4.801, p = 0.091. The mean rank was 132.18, 109.90, and 115.70 for small, medium, and large scale companies respectively.

5.1.3.7.8 NBCFs’ perceptions and company ownership status

Null Hypothesis H08 – “There is no significant difference in the NBCFs’ perceptions of material wastes based on a company’s ownership status”.

The null hypothesis was accepted based on the Kruskal-Wallis H test, χ2 (3) = 2.082, p = 0.556. The mean rank for company ownership status was 125.60 for privately owned, 120.75 for partnership, 102.78 for government-owned and 114.85 for public limited companies.

5.1.3.7.9 NBCFs’ perceptions and a company’s main construction activity

Null Hypothesis H09 – “There is no significant difference in the NBCFs’ perceptions of material wastes based on a company’s main construction activity”.

The null hypothesis was accepted based on the Kruskal-Wallis H test result, χ2 (3) = 3.651, p = 0.302. The mean rank was 121.65, 146.29, 107.61, and 87.38 for new build, maintenance/repair, renovation, and demolition/deconstruction activities respectively.

5.1.3.8 Relationship between Awareness, Attitudes and Perceptions

H10: Awareness of material waste is positively related to perceptions To determine the relationship between the NBCFs’ awareness of material waste and their perceptions of waste, a Spearman correlation (Table 5.1) was conducted. Although there was a weak, positive correlation between their awareness and perceptions, it was not statistically significant (r = 0.049, p = 0.452). Therefore, the hypothesis was rejected.

162

H11: Awareness of material waste is positively related to attitudes Based on the value of the test statistics (r = 0.113, p = 0.079), the hypothesis was rejected. The correlation analysis indicates a weak, positive correlation between the NBCFs’ awareness and attitudes to material waste which was not statistically significant.

H12: Attitudes to material waste are positively related to perceptions There is a weak strength relationship between the NBCFs’ attitudes to material waste and their perceptions. The test result (r = 0.204, p 0.001) indicates a positive correlation. Therefore,

H12 was therefore accepted. ≤ Table 5.14: Spearman rho correlation matrix

Correlations Awareness Attitude Perceptions Spearman's Awareness Correlation Coefficient 1.000 rho Sig. (2-tailed) . N 243 Attitude Correlation Coefficient .113 1.000 Sig. (2-tailed) .079 . N 243 243 Perceptions Correlation Coefficient .049 .204** 1.000 Sig. (2-tailed) .452 .001 . N 243 243 243 **. Correlation is significant at the 0.01 level (2-tailed). Correlation Matrix Awareness Attitude Perceptions Spearman's Awareness - rho Attitude .113 - Perceptions .049 .204** - **. Correlation is significant at the 0.01 level (2-tailed).

RQ3. What are the current approaches adopted by the Nigerian building construction firms (NBCFs) to minimise material waste at design, procurement and construction phases? 5.1.3.9 Design Approaches Implemented in Practice by NBCFs Twenty-four design approaches for minimising and managing construction material wastes were identified. Results show that the top five are ‘uniform design’ (RII = 0.686), ‘consider material logistics’ (RII = 0.685), ‘collaborate with others in the supply chain’ (RII = 0.672), ‘consider maintenance, service and replacement requirements for each component’ (RII = 0.672) and ‘consider impact of material on the environment’ (RII = 0.661), respectively, while the least ranked approach (RII = 0.475) was to ‘specify recycled content in design’ (see Table 5.15).

163

Table 5.15: Design approaches to material waste minimisation

Design for reuse and recovery NBU RU USP UMP UAP W RII Rank (DfRR) Reuse building components and 22 66 105 44 5 670 0.554 1 materials Reuse existing buildings and landscapes 20 67 117 34 4 661 0.546 2 Use recycled building components and 39 78 90 33 3 612 0.503 3 materials Design with less variety of materials 18 52 101 31 9 594 0.492 4 Design for off-site construction (DfOC) Use off-site prefabricated pods i.e. 12 31 98 80 19 783 0.652 1 kitchen cabinets, railings, doors etc. Use off-site prefabricated and pre-cut 10 56 100 66 10 736 0.608 2 building elements Use off-site prefabrication of structural 24 66 95 50 8 681 0.560 3 elements Use modular construction 36 63 87 40 15 658 0.546 4 Design for materials optimisation (DfMO) Uniform design, e.g. room sizes, floor 5 31 89 89 28 830 0.686 1 to ceiling heights and material sizes Consider maintenance, service and 2 44 91 77 29 816 0.672 2 replacement requirements of each component Simplify the building form, layout and 8 29 118 66 21 789 0.652 3 elements Use local materials 7 32 122 61 19 776 0.644 4 Specify recycled content in design 47 96 66 27 6 575 0.475 5 Design for waste efficient procurement (DfWEP) Consider material logistics e.g. Just-in- 8 32 87 77 37 826 0.685 1 time deliveries Collaborate with others in the supply 6 41 96 59 41 817 0.672 2 chain Consider impact of material on the 11 52 64 82 33 800 0.661 3 environment Specify responsibly sourced materials 11 45 86 77 23 782 0.646 4 Prepare a site waste management plan 31 59 70 48 32 711 0.593 5 Reduce packaging requirements in 19 70 98 46 10 687 0.565 6 materials procurement Use contractual documents to set waste 33 79 65 49 16 662 0.547 7 performance requirements Design for deconstruction and flexibility (DfDF) Use flexible construction methods to 6 56 95 67 19 766 0.630 1 enable change of use Use precast concrete and/or steel 15 47 116 51 11 716 0.597 2 frames Consider reuse potential once design 21 80 79 43 19 685 0.566 3 life is complete Use lime mortar and/or mortar-less 49 87 57 38 12 606 0.498 4 masonry to facilitate reuse NBU – Never been used, RU – Rarely used, USP – Used in some projects, UMP – Used in most projects, UAP – Used in all projects, W – Weighted average and RII – Relative importance index.

164

All of these approaches are known as ‘Eco-design’, ‘design for environment’ or ‘principles of designing out waste’ and were adopted from the literature (WRAP, 2009a; Zero Waste Scotland, 2016; Osmani, 2012) in five categories, namely: design for reuse and recovery (DfRR), design for off-site construction (DfOC), design for materials optimisation (DfMO), design for waste efficient procurement (DfWEP), and design for deconstruction and flexibility (DfDF). The relative importance of these approaches was measured through the questionnaire survey on a five-point Likert scale ranging from ‘never been used’ to ‘used in all projects’. Respondents were asked how often they adopt each approach on their construction projects. The relative importance of these design approaches and their rankings are presented in Table 5.16. The result shows that DfMO ranked 1st (RII = 0.625), DfWEP 2nd (RII = 0.624), DfOC 3rd (RII = 0.592), DfDF 4th (RII = 0.573), while DfRR ranked 5th (RII = 0.524).

Table 5.16: Categories of design approaches to material waste minimisation

Eco Design/Design for the Environment Average RII Cronbach’s Alpha Rank Design for materials optimisation (DfMO) 0.625 0.705 1 Design for waste efficient procurement 0.624 0.877 2 (DfEWP) Design for off-site construction (DfOC) 0.592 0.751 3 Design for deconstruction and flexibility 0.573 0.827 4 (DfDF) Design for reuse and recovery (DfRR) 0.524 0.755 5

The structure of the interrelationships among the design approaches was investigated to reduce their large number (i.e. 24 design approaches). Results details are outlined in Appendix O. The test statistics for sphericity (Bartlett’s Test of Sphericity) was χ2 (276) = 2388.719; p < 0.001) (see Appendix O1). The Kaiser Meyer Olkin (KMO) statistic yielded a value of 0.902. A potential correlation of design approaches to waste minimisation is presented in Appendix O. For instance, there was a strong, positive correlation (r = 0.609) between ‘use contractual documents to set waste performance requirements’ and ‘prepare a site waste management plan’, which was statistically significant (p < 0.0001). Furthermore, there was a weak, positive correlation (r = 0.190) between ‘simplify the building form, layout and elements’ and ‘prepare a site waste management plan’, which was statistically significant (p = 0.003).

The communalities (amount of variance in each variable) and the sample size’s adequacy (Field, 2005) were first established. The result indicates an average communality value of 0.610 (see Appendix O2), which suggests an adequate sample size. Thereafter, the 24 items for design approaches to construction waste minimisation were subjected to principal component analysis

165

(PCA) using SPSSv24. The PCA analysis (see Appendix O3) indicates five components with eigenvalues greater than 1 were extracted using factor loading of 0.30 as the benchmark. Component 1 explains 35.969% of the variance, while components 2, 3, 4, and 5 explain 8.567%, 6.634%, 5.029%, and 4.836% of the variance respectively. The scree plot (Figure 5.2) indicates a clear break after the 5th component, which prompted the decision to retain five components for further examination. Varimax rotation was performed to understand these five components. Table 5.17 shows that all variables significantly load onto one component, and that explained a total of 61.035% of the variance. The contributions of each component are: component 1 (DfEWP) 17.826; component 2 (DfDF) 13.274%; component 3 (DfOC) 10.135%; component 4 (DfMO) 10.083%; and component 5 (DfRR) 9.716%. The initial categorisation adopted from the literature was retained due to the assessment of the integral relationships between the variables under each component. However, two variables (design with fewer materials and specify recycled content in design) moved from their initial categories (DfRR and DfMO) to new categories (DfOC and DfDF) respectively (see Appendix O4 & O5).

Table 5.17: Rotated Component Matrix

Design Approaches Component 1 2 3 4 5 (DfWEP) (DfDF) (DfOC) (DfMO) (DfRR) Consider materials logistics e.g. .763 Just-in-time deliveries Consider impact of material on the .734 environment Collaborate with others in the .726 supply chain Reduce packaging requirements in .723 materials procurement Prepare a Site Waste Management .701 Plan Specify responsibly sourced .614 materials Use contractual documents to set .591 waste performance requirements Use lime mortar and/or mortar- .770 less masonry to facilitate reuse Use precast concrete and/or steel .689 frames Use flexible construction methods .660 to enable change of use Consider reuse potential once .656 design life is complete Specify recycled content in design .473

166

Design Approaches Component 1 2 3 4 5 (DfWEP) (DfDF) (DfOC) (DfMO) (DfRR) Use off-site prefabricated pods i.e. .800 kitchen cabinets, railings, doors etc. Use off-site prefabricated and pre- .656 cut building elements Use off-site prefabrication of .617 structural elements Design with less variety of .546 materials Use modular construction .524 Simplify the building form, layout .772 and elements Uniform design, e.g. room sizes, .627 floor to ceiling heights and material sizes Consider maintenance, service and .608 replacement requirements of each component Use local materials .535 Reuse building components and .815 demolition materials Use recycled building components .787 and demolition materials Reuse existing buildings and .617 landscapes Cronbach Alpha 0.877 0.827 0.751 0.705 0.755 Extraction Method: Principal Component Analysis. Rotation Method: Varimax with Kaiser Normalization. a. Rotation converged in 7 iterations.

167

Figure 5.2: Scree plot – Design Approaches

5.1.3.10 Procurement Approaches Implemented by NBCFs In any construction project, procurement is vital and, as such, plays a significant role in minimising material waste. This prompted an investigation into the procurement approaches adopted by the NBCFs to minimise wastes. Overall, 13 procurement approaches were identified from the literature and presented to the respondents. They were asked to state the extent to which they applied those procurement approaches on their projects. Using the RII, their responses were analysed. The results in Table 5.18 show that the most practised procurement approach is to ‘purchase durable materials’ (RII = 0.831), while the least is to ‘ask suppliers to commit to waste reduction goals’ (RII = 0.574).

Table 5.18: Procurement approaches to material waste minimisation

Procurement approaches Never Rarely Used in Used in Used in W RII Rank been used some most all used projects projects projects Purchase durable 2 6 35 107 90 997 0.831 1 materials Examine the need for the 7 16 71 82 67 915 0.753 2 material Adopt just-in-time (JIT) 11 36 78 70 48 837 0.689 3 delivery of materials Purchase from local 6 21 101 86 27 830 0.688 4 suppliers

168

Procurement approaches Never Rarely Used in Used in Used in W RII Rank been used some most all used projects projects projects Reduce the hazardous 17 46 63 73 44 810 0.667 5 material content in purchases, including toxicity Consider the end-of-life 16 47 59 80 39 802 0.665 6 options, including the reuse, repair, recycling and disposal options Consider alternatives, such 7 48 87 73 28 796 0.655 7 as reusing, refurbishing or reconditioning existing products or their components to extend their lives Choose materials with the 15 46 81 68 33 787 0.647 8 least environmental and /or social impact Purchase multifunctional 10 49 89 69 26 781 0.643 9 materials Consider the 24 44 71 73 31 772 0.635 10 environmental management practices of suppliers/manufacturers Choose materials with low 17 50 86 61 27 754 0.625 11 environmental impact Verify the social 31 51 75 56 29 727 0.601 12 responsibility and ethical behaviour of manufacturers and suppliers of the product Ask suppliers to commit to 39 65 57 51 30 694 0.574 13 waste reduction goals

The factorability of the 13 procurement approaches was examined. The result (see Appendix P) indicates that all items are significantly correlated with each other, suggesting reasonable factorability. The value of the KMO measure of sampling was 0.913 (Appendix P1), much greater than the recommended value of 0.5 (Kaiser, 1974). Bartlett’s test of sphericity was statistically significant (χ2 (78) = 1435.151, p < 0.001). The communalities with an average value of 0.560 further confirmed the interrelationship between items (Appendix P2). Based on these indicators, factor analysis was considered appropriate for reducing the number of factors into limited entities.

169

Using the PCA analysis with an eigenvalue greater than 1 and factor loading cut off point of 0.3, two factors were extracted (see Table 5.19). These factors explained a total 56.953% of the variance for the entire set of variables. Factor 1 accounted for 46.427% while Factor 2 explained 10.525% (Appendix P3). As shown in Figure 5.3, the scree plot indicated a clear break after the 2nd component. As a result, varimax rotation was employed and a total of 56.953% of the variance was explained by the result. The Cronbach’s alpha for the 13-item scale is 0.901, which indicates good reliability and internal consistency. The first factor was labelled ‘Act Green,’ with an eigenvalue of 6.036 comprising nine variables, while the second factor, labelled ‘Buy Green,’ had an eigenvalue of 1.368 comprising four variables (Table 5.19).

Table 5.19: Rotated Component Matrix – Procurement Approaches

Rotated Component Matrixa Component 1 2 (Act (Buy Green) Green) Consider the environmental management practices of .840 suppliers/manufacturers Verify the social responsibility and ethical behaviour of .810 manufacturers and suppliers of the product Reduce the hazardous material content in purchases, including .788 toxicity Consider the end-of-life options, including the reuse, repair, .784 recycling and disposal options Ask suppliers to commit to waste reduction goals .772 Choose materials with the least environmental and/or social .679 impact Choose materials with low environmental impact .576 Adopt just-in-time (JIT) delivery of materials .574 Consider alternatives, such as reusing, refurbishing or .552 reconditioning existing products or their components to extend their life Purchase from local suppliers .763 Examine the need for the material .696 Purchase durable materials .679 Purchase multi-functional materials .485 Cronbach Alpha 0.905 0.689 Extraction Method: Principal Component Analysis. Rotation Method: Varimax with Kaiser Normalization. a. Rotation converged in 3 iterations.

170

Figure 5.3: Scree plot - Procurement Approaches 5.1.3.11 Sustainable Construction Approaches Implemented by NBCFs The construction approaches implemented by the NBCFs were investigated. Respondents were asked to examine a list of sustainable approaches adopted from the literature. In total, 15 approaches were presented, and responses were given on a five-point Likert scale ranging from ‘never been used’ to ‘used in all projects’. Using the relative importance index analysis, the result (Table 5.20) suggests that ‘stock control measures’ was ranked 1st, while ‘effective teamwork among stakeholders’ and ‘avoid excavating unnecessary soil’ were ranked 2nd and 3rd respectively. Modern trends in the construction industry, such as ‘adopting BIM and ICT tools’ and ‘lean construction’ were ranked 11th and 13th respectively. The least practiced approaches were to ‘appoint a waste management contractor’ which ranked 14th and to ‘use no-dig or trenchless technology’ ranked 15th.

Table 5.20: Sustainable construction approaches to material waste minimisation

Sustainable Never Rarely Used in Used in Used in W RII Rank construction been used some most all approaches used projects projects projects Stock control measures 7 21 61 83 68 904 0.753 1 (e.g. stock taking) Effective teamwork 6 20 77 82 58 895 0.736 2 among stakeholders Avoid excavating 9 28 68 86 52 873 0.718 3 unnecessary soil

171

Sustainable Never Rarely Used in Used in Used in W RII Rank construction been used some most all approaches used projects projects projects Use excavated soil 10 31 64 83 52 856 0.713 4 elsewhere on the same construction site Educate construction 13 27 74 84 45 850 0.699 5 and management teams on waste reduction Conduct 13 42 76 62 50 823 0.677 6 comprehensive feasibility studies Set targets for 10 47 67 80 36 805 0.671 7 allowable waste Identify construction 8 43 80 74 34 800 0.669 8 activities that can reuse materials Make waste reduction 26 49 66 62 40 770 0.634 9 efforts financially beneficial Improved construction 19 47 82 64 29 760 0.631 10 methods e.g. Industrialised building system Adopt building 37 49 56 67 31 726 0.605 11 information modelling (BIM) and ICT tools Provide space on site 21 61 80 52 25 716 0.599 12 for the management of C&D waste Lean construction 35 60 86 47 14 671 0.554 13 Appoint a waste 67 63 56 38 16 593 0.494 14 management contractor Use no-dig or 61 68 67 32 14 596 0.492 15 trenchless technologies

Fifteen questions relating to sustainable construction approaches were cross examined for interrelationships. The results suggest that all items are significantly correlated (see Appendix Q). An examination of the KMO measure of sampling adequacy revealed that the sample was factorable (KMO = 0.915). Similarly, the Bartlett’s test of sphericity (χ2 (105) = 1571.909, p < 0.001) was statistically significant (Appendix Q1) while an average value (0.623) of communalities suggest a positive relationship between the items (Appendix Q2).

A principal component analysis (eigenvalue >1) with a varimax rotation of the 15 sustainable construction approaches was conducted with a Cronbach’s alpha value of 0.911, which implies

172

good reliability and internal consistency. The PCA result is shown in Table 5.21. The analysis returned a three-factor solution when loadings less than 0.30 were excluded. The scree plot (Figure 5.4) also confirms a clear break after the third component. These three factors are responsible for a total of 62.273% of the total variance where factor 1 explained 45.103% of the variance. Factor 2 and 3 explained 10.034% and 7.136% of the variance respectively (Appendix Q3). The first factor, labelled ‘Strategies’ explained 25.653% of the variance, comprising six variables with an eigenvalue of 6.765. The second factor, labelled ‘Techniques,’ had an eigenvalue of 1.505 comprising five variables, which explained 18.421% of the variance, while the third factor, labelled ‘Operations,’ with four variables and an eigenvalue of 1.070, explained 18.199% of the variance.

Table 5.21: Rotated Component Matrix – Sustainable Construction Approaches

Component 1 2 3 Construction Approaches (Strategies) (Techniques) (Operations) Educate construction and management .728 teams on waste reduction Conduct comprehensive feasibility studies .704 Set targets for allowable waste .699 Effective teamwork among stakeholders .678 Improved construction methods e.g. .673 Industrialised building system Make waste reduction efforts financially .571 beneficial Use no-dig or trenchless technologies .861 Appoint a waste management contractor .675 Provide space on site for the management .627 of C&D waste Lean construction .579 Adopt building information modelling .518 (BIM) and ICT tools Avoid excavating unnecessary soil .818 Use excavated soil elsewhere on the same .780 construction site Stock control measures (e.g. stocktaking) .595 Identify construction activities that can .554 reuse materials Cronbach Alpha 0.844 0.826 0.766 Extraction Method: Principal Component Analysis. Rotation Method: Varimax with Kaiser Normalization. a. Rotation converged in 7 iterations.

173

Figure 5.4: Scree plot of sustainable construction approaches 5.1.3.12 Hypotheses Testing (B) To determine the significant differences between the NBCFs’ characteristics (i.e. ownership status, size, age, and main construction activity) and their approaches to waste minimisation, the Kruskal-Wallis test was conducted. Tables 5.22, 5.23, 5.24, and 5.25 shows the results of the null hypothesis postulated.

5.1.3.12.1 NBCFs’ waste minimisation approaches and company ownership status

Null Hypothesis H13 – “There is no statistically significant difference in the NBCFs’ waste minimisation approaches based on company ownership status”.

A Kruskal-Wallis H test shows no statistically significant difference between NBCFs’ procurement approaches (χ2 (3) = 2.440, p = 0.486), construction approaches (χ2 (3) = 0.213, p = 0.975), design approaches (χ2 (3) = 3.353, p = 0.340) and company ownership status (Table 5.22).

174

Table 5.22: Kruskal Wallis Test for waste minimisation approaches and company ownership status Test Statisticsa,b Procurement Approach Construction Approach Design Approach Chi-Square 2.440 .213 3.353 df 3 3 3 Asymp. Sig. .486 .975 .340 a. Kruskal Wallis Test b. Grouping Variable: Company ownership status

5.1.3.12.2 NBCFs’ waste minimisation approaches and company size

Null Hypothesis H14 – “There is no statistically significant difference in the NBCFs’ waste minimisation approaches based on company size”.

The test result (Table 5.23) shows no significant difference between the NBCFs’ procurement approaches (χ2 (2) = 1.946, p = 0.378), design approaches (χ2 (2) = 2.606, p = 0.272) and company size. However, there is a significant difference between the NBCFs’ construction approaches (χ2 (2) = 8.212, p = 0.016) and company size. A post hoc test (Dunn’s test) further revealed that there is a significant difference (p = 0.014) between medium and large scale companies and their construction approaches. Based on this result, the null hypothesis was rejected.

Table 5.23: Kruskal Wallis Test for waste minimisation approaches and company size Test Statisticsa,b Procurement Approach Construction Approach Design Approach Chi-Square 1.946 8.212 2.606 df 2 2 2 Asymp. Sig. .378 .016 .272 a. Kruskal Wallis Test b. Grouping Variable: company size

5.1.3.12.3 NBCFs’ waste minimisation approaches and a company’s age

Null Hypothesis H15 – “There is no statistically significant difference in the NBCFs’ waste minimisation approaches based on the age of a company”.

A Kruskal-Wallis test result shown in Table 5.24 reveals no statistically significance difference between the NBCFs’ procurement approaches (χ2 (4) = 4.016, p = 0.404), construction

175

approaches (χ2 (4) = 3.631, p = 0.458), design approaches (χ2 (4) = 3.988, p = 0.408), and the age categories of companies.

Table 5.24: Kruskal Wallis Test for waste minimisation approaches and company age Test Statisticsa,b Procurement Approach Construction Approach Design Approach Chi-Square 4.016 3.631 3.988 df 4 4 4 Asymp. Sig. .404 .458 .408 a. Kruskal Wallis Test b. Grouping Variable: company age

5.1.3.12.4 NBCFs’ waste minimisation approaches and a company’s main construction activity

Null Hypothesis H16 – “There is no statistically significant difference in the NBCFs’ waste minimisation approaches based on a company’s main construction activity”.

A Kruskal-Wallis test was conducted to evaluate the differences between the procurement, construction, and design approaches and the NBCFs’ main construction activity. Table 5.25 shows no statistically significant difference between construction approaches (χ2 (3) = 7.437, p = 0.408) and a company’s main construction activity. The result also shows that there is a statistically significant difference between procurement approaches (χ2 (3) = 13.796, p = 0.003), design approaches (χ2 (3) = 16.664, p = 0.001) and a company’s main construction activity. A follow-up test (Dunn’s test) was conducted to evaluate the differences among procurement approaches. The result revealed a significant difference (p ≤ 0.001) between ‘new build’ and ‘maintenance/repair’ activities of the companies. Similarly, a Dunn’s test revealed a significant difference (p ≤ 0.001) between ‘new build’ and ‘maintenance/repair’ activities. Furthermore, the test shows a significant difference (p = 0.005) between ‘renovation’ and ‘maintenance/repair’ activities of the companies. Table 5.25: Kruskal Wallis Test for waste minimisation approaches and a company’s main construction activity Test Statisticsa,b Procurement Approach Construction Approach Design Approach Chi-Square 13.796 7.437 16.664 df 3 3 3 Asymp. Sig. .003 .059 .001 a. Kruskal Wallis Test b. Grouping Variable: Company’s main construction activity

176

RQ4. To what extent are the 3R principles being adopted by the Nigerian building construction firms? 5.1.3.13 The 3R Approaches Implemented by NBCFs The current status of the ‘reduce, reuse and recycling’ (3Rs) approaches adopted by the NBCFs was investigated. Ten approaches were adopted from the literature and presented to respondents for ranking on a five-point Likert scale, ranging from ‘never been used’ to ‘used in all projects’. Using the RII, their responses were analysed. The results shown in Table 5.26 disclose that ‘reuse of formwork and scaffolding’ was ranked as the most frequent (RII = 0.788) approach used. The last three approaches relate to recycling of materials and this further confirms that recycling of construction materials is not common in Nigeria. These approaches, as they ranked, are, ‘use recycled materials’ (8th), ‘send waste materials to recycling facilities’ (9th) and ‘recycle waste on site’ (10th).

Table 5.26: The 3R approaches to material waste minimisation

3Rs’ approaches Never Rarely Used in Used in Used in W RII Rank been used some most all used projects projects projects Use reusable formwork 3 10 61 93 76 958 0.788 1 and scaffolding Re-use of materials on- 3 18 90 75 56 889 0.735 2 site On-site sorting and 9 48 83 61 42 808 0.665 3 segregation of material waste Re-use of materials on 10 38 96 62 36 802 0.663 4 different site Evaluate if salvage of 13 57 85 59 26 748 0.623 5 used-products is possible Use systems that favour 19 65 79 52 27 729 0.602 6 segregation into their elements at the end of their useful lives Use skips for segregation 31 73 80 41 17 666 0.550 7 of specific materials Use recycled materials 31 67 88 44 12 665 0.549 8 Send waste materials to 81 58 55 31 18 576 0.474 9 recycling facility Recycle waste on site 87 66 46 27 17 550 0.453 10

The interrelationships between the approaches were examined and the result shows significant correlation of all the items (see Appendix R). The KMO measure of sampling adequacy was

177

conducted and the result indicates the value, 0.842 (Appendix R1), which is well above the minimum requirement of 0.5 (Kaiser, 1974). This suggests that the sample size was adequate (Williams et al., 2012). Also, the Bartlett’s test of sphericity was conducted as part of the criteria for factorability. The result (χ2 (45) = 1188.542, p < 0.001) was statistically significant, suggesting that the sample was factorable. An average communalities value of 0.7492 (Appendix R2) confirms the existence of mutual relationships among the items.

Using the PCA with an eigenvalue of 1 and cut-off point of 0.30, three factors were extracted. A clear break after the third component can be seen on the Scree plot (Figure 5.5). When varimax rotation was employed, the three factors explained a total of 74.919% of the variance (Appendix R3). Factor 1 explained 28.233%, factor 2, 23.663% and factor 3, 23.034%. This indicates good reliability and internal consistency of the analysis based on the Cronbach’s alpha value of 0.865. The factors extracted were labelled after the 3R principle (reduce, reuse, and recycle) based on an assessment of the relationships among the variables, the initial categorisation, ease of description and consistency. The first factor, reduce, had an eigenvalue of 4.579 comprising four variables. The second factor, recycle, had an eigenvalue of 1.751 comprising three variables, while the last factor, reuse, had an eigenvalue of 1.161 comprising three factors (Table 5.27).

Figure 5.5: Scree plot of the 3R approaches

178

Table 5.27: Rotated component matrix of the 3R approaches

Rotated Component Matrixa Component 1 2 3 (Reduce) (Recycle) (Re use) On-site sorting and segregation of material wastes .815 Use systems that favour segregation of materials into .824 their elements at the end of their useful lives Use skips for segregation of specific materials .777 Evaluate if salvage of used-products is possible .777 Use reusable formwork and scaffolding .843 Re-use of materials on-site .883 Re-use of materials on different site .782 Use recycled materials .788 Send waste materials to recycling facility .846 Recycle waste on-site .815 Cronbach Alpha 0.872 0.832 0.816 Extraction Method: Principal Component Analysis. Rotation Method: Varimax with Kaiser Normalization. a. Rotation converged in 6 iterations.

RQ5. What policies or legislative measures are required for effective waste minimisation in the NCI?

5.1.3.14 Waste Minimisation Policies/Legislative Measures The questionnaire asked about 10 established waste minimisation strategies and these were presented to the NBCFs. They were asked to rate the importance of these strategies to their firms on a five-point Likert scale ranging from ‘not important’ to ‘very important’. A brief description of some strategies was provided to aid respondents’ understanding. Using the RII, the ranking of strategies presented in Table 5.28 reveals that ‘site waste management planning’ (RII 0.867); ‘appoint a waste manager’ (RII 0.828); and ‘construction waste charging scheme’ (RII 0.825) were ranked 1st, 2nd, and 3rd respectively. The least ranked strategies are ‘extended producer responsibility’ (8th); ‘contractors’ willingness to pay’ (9th); and ‘landfill ban’ (10th).

179

Table 5.28: Waste minimisation policies/measures

Waste Not Less Neutral Important Very W RII Rank Minimisation important important important Policies/Measures Site waste 0 6 16 110 108 1040 0.867 1 management planning (SWMP) Appoint a waste 1 15 23 112 91 1003 0.828 2 manager Construction waste 1 6 34 122 80 1003 0.825 3 disposal charging scheme Financial incentives 0 9 31 139 62 977 0.811 4 for operatives Stepwise incentive 1 14 35 141 52 958 0.788 5 system (SIS) Use of waste 1 17 30 139 53 946 0.788 6 prediction tools Pay-as-you-throw 3 18 43 125 53 933 0.771 7 (PAYT) Extended producer 2 15 45 134 44 923 0.769 8 responsibility Contractor’s 0 18 41 146 35 918 0.765 9 willingness to pay (WTP) Landfill ban 8 32 58 90 52 866 0.722 10

The correlation (see Appendix S) of all items was significant, suggesting interrelationships between the items. The KMO measure of sampling adequacy (0.858) reveals that the sample was adequate (Appendix S1). Similarly, the Bartlett’s test of sphericity showed a significant level (χ2 (45) = 641.433, p < 0.001), while an average communality value of 0.515 (Appendix S2) confirms the relationship between the items. Therefore, the sample was accepted for factorisation.

The 10-item waste minimisation strategies returned a Cronbach’s alpha value of 0.822, and two factors with an eigenvalue greater than 1 at 0.30 cut-off point were extracted using the PCA with varimax rotation. These factors explained almost 52% of the variability in the original variables. Factor 1 explained 28.806%, while factor 2 explained 24.729% (see Appendix S3). The first factor can be described as “recommended” strategies, which accounted for four underlying variables with an eigenvalue of 3.993, while the second factor, referred to as “required” strategies, comprised six variables with an eigenvalue of 1.160 (see Table 5.29).

180

Table 5.29: Rotated component matrix of waste minimisation policies

Rotated Component Matrixa Component 1 2 Recommended Required Construction waste disposal charging scheme (to encourage .772 the construction workforce to consider 3R principles before disposal) Site waste management plan (SWMP) .732 Extended Producer Responsibility (producers’ .663 responsibilities extend across the life cycle of their products especially when the products are discarded as waste) Step-wise incentive system (an award given to those .659 producing low levels of waste) Pay-as-you-throw (PAYT)/landfill charging scheme .767 (requires construction workforce to pay for the amount of waste that they produce) Landfill ban (outright ban on the disposal of .704 reusable/recyclable construction materials) Financial incentives for operatives (labourers) to sort and .596 segregate waste Appoint a waste manager (new position where someone is .596 appointed to coordinate waste management procedures on site) Use waste prediction tools (to generate waste forecasts) .513 Contractor’s willingness to pay (WTP) for waste .465 management Cronbach Alpha 0.742 0.748 Extraction Method: Principal Component Analysis. Rotation Method: Varimax with Kaiser Normalization. a. Rotation converged in 3 iterations.

5.1.3.15 Waste Minimisation Implementation Methods An investigation of appropriate implementation methods for waste minimisation strategies was conducted. Six proven methods were identified and presented to the NBCFs. They were asked to prioritise those methods using positions from 1st to 6th. Table 5.30 provides a summary of the results. Overall, ‘policy and goal on waste minimisation’ was ranked 1st, while ‘international cooperation’ was ranked 6th. The median for each implementation method is provided in Table 5.30. To test for significant differences between the methods, the Friedman test was conducted. The result (χ2 (5) = 233.808, p < 0.0001) is statistically significant at 5%

181

significance level (Table 5.30). To determine where the difference actually occurs, a Bonferroni correction was performed after post hoc analysis with Wilcoxon signed-rank tests, resulting in p < 0.003. The result reveals statistically significant negative differences in almost all the methods except the ‘policy and goal’ and ‘education and training’ (Z = -2.217, p = 0.027); ‘legislative system’ and ‘cooperation and communication among stakeholders’ (Z = - 1.553, p = 0.120); ‘legislative system’ and ‘promotion of research and technology’ (Z = -2.888, p = 0.004); ‘legislative system’ and ‘education and training’ (Z = -1.688, p = 0.091); and ‘promotion of research and technology’ and ‘cooperation among stakeholders’ (Z = -1.764, p = 0.078).

Table 5.30: Waste minimisation implementation and Friedman test statistics

Implementation Mean Standard Percentiles Rank methods Deviation 25th 50th (Median) 75th Policy and goal 2.53 1.61149 1.000 2.000 4.000 1 Education and training 2.97 1.79623 1.000 3.000 4.000 2 Legislative system 3.28 1.61216 2.000 3.000 5.000 3 Cooperation and 3.53 1.33987 3.000 4.000 5.000 4 communication among stakeholders Promotion of research 3.75 1.37223 3.000 4.000 5.000 5 and technology International cooperation 4.93 1.44573 4.000 6.000 6.000 6 Friedman Test Statistics N χ2 df Asymp. Sig. 243 233.808 5 .000 a. Friedman Test

RQ6. Can a circular-economy-based waste minimisation framework be adapted for minimising construction waste in the Nigerian construction industry?

5.1.3.16 NBCFs’ Waste Minimisation Policy To develop a circular-economy-based waste minimisation framework for the NCI, the existing policies on construction waste minimisation were identified. Respondents were asked the question: “Does your company have a waste minimisation policy?” The result, presented in Figure 5.6, shows that more than half (52.3%) of the companies have a waste minimisation plan, while 38.3% do not.

182

60 52.3 50

40 38.3

9.5 10

0 Yes No I do not know

Figure 5.6: Graphical representation of NBCFs’ waste minimisation policy

5.1.3.17 NBCFs’ Willingness to Adopt New Construction Waste Minimisation Methods The NBCFs were asked to respond to a statement about their willingness to adopt new construction waste minimisation methods. Their responses were rated on a five-point Likert scale ranging from ‘strongly disagree’ to ‘strongly agree’. A summary of the results is presented in Figure 5.7, indicating that almost half (49%) of the respondents agreed that their company is willing to adopt a new construction waste minimisation method, while 40.3% strongly agreed. Only 0.8% strongly disagreed while 1.6% disagreed.

49 50 40.3 40

30 Percentage 20

10 8.2 0.8 1.6 0 Strongly disagree Disagree Neutral Agree Strongly agree Level of agreement

Figure 5.7: Graphical representation of NBCFs’ willingness to adopt new construction waste minimisation method

183

5.1.4 Summary of Quantitative Results Section 5.1 has analysed the quantitative data where the results show that the NBCFs generate concrete, ceramic and stone wastes, while the main design cause of waste is design variations. The main causes of waste at the procurement and construction phases are substandard materials and quality of supervision respectively. The respondents demonstrated a high level of awareness and positive attitudes to material waste; however, their attitudes were positively related to their perception of material wastes. Furthermore, the results revealed that the main disposal method among the NBCFs is landfilling. Their main design approach to waste minimisation is to design for waste efficient procurement, while designing for reuse and recovery is the least considered design option. Similarly, their main procurement approach is to purchase durable materials and the least adopted approach is to ask suppliers to commit to waste reduction goals. Two factors (act green and buy green) were extracted from the procurement approaches identified as examples of good practices. As for the construction approaches, the results identified stock control measures as the main approach, while the least is to use no dig or trenchless technology. A Kruskal-Wallis test followed by a post hoc test (Dunn’s test) revealed a significant difference between medium and large-scale companies and their construction approaches to minimising material waste. Also, there was a significant difference between the new build and maintenance/repair activities of the companies and their procurement approaches, as well as their design approach. Similarly, renovation and maintenance/repair activities and their design approaches were significantly different. For the 3R approaches, the results revealed that the main approach is to use reusable formwork and scaffolding, while the least is to recycle waste on site. Similarly, site waste management planning was considered as the main waste minimisation strategy while the least considered was a landfill ban. With respect to the implementation methods for the strategies identified, the results indicated that policies and goals were ranked first, while international cooperation was ranked last. Finally, most of the firms indicated that they have a waste minimisation policy in place, while more than half are willing to adopt a new waste minimisation method.

5.2 Qualitative Interpretation of Results This section presents the results obtained after analysis of the interview data. A total of 65 semi-structured face-to-face interviews were conducted with building construction professionals working on over 10 building projects in Lagos, Nigeria. A separate interview was held with a representative of the government agency responsible for waste management. The

184

purpose was to explore the interviewees’ understanding, perceptions, and experiences of minimising construction material waste. Their opinions and comments were audio recorded and transcribed by the researcher. Thereafter NVivo 11 QDA software was used to analyse the transcripts. Important segments of the transcripts were coded into themes, with a recurring pattern best suited to provide answers to the research questions. For the purpose of data reduction and conceptualisation, the coded segments were grouped into categories and presented in a narrative form. The research questions have been used to organise the presentation of results in the rest of this section.

5.2.1 Demographics Table 5.31 outlined the demography of interviewees. Construction professionals, including architects, engineers, project managers and quantity surveyors, as well as main contractors, sub-contractors and foremen from 10 building construction projects in Lagos, Nigeria participated in the study (Table 5.31). A summary of the construction sites in terms of project type and location is presented in Table 5.32 and Figure 5.8. Project sites and interviewees are represented by a code (See Table 5.32). In selecting interviewees, age and gender were not considered important whereas years of experience and educational qualifications were. All interviewees met the inclusion criteria of a construction experience of at least three years. The average years of experience of all participant was 13.6 years, while the minimum qualification was an Ordinary National Diploma (OND). Table 5.31: Demography of interviewees

Characteristics Gender Interviewees Male 61 interviewees Female 4 interviewees (SC8, QS10, E10, E6) Years of experience Interviewees Average participant’s 13.6 years experience 3 – 5 years 16 Interviewees 6 – 10 years 18 Interviewees 11 – 15 years 11 Interviewees 16 – 20 years 6 Interviewees 21 – 25 years 6 interviewees 26 – 30 years 4 Interviewees Above 31 years 4 Interviewees Educational level Qualification Minimum Ordinary National Diploma (OND) Maximum Masters (MSc.) Position/role of interviewees Interviewees (codes)

185

Characteristics Architect 9 Interviewees (A1, A3, A4, A5, A6, A7, A8, A9, A10) Engineer 10 Interviewees (E1 – E10) Foreman 9 Interviewees (F1, F2, F3, F4, F5, F7, F8, F9, F10) Main contractor 10 Interviewees (MC1 – MC10) Project manager 9 Interviewees (PM1, PM2, PM4, PM5, PM6, PM7, PM8, PM9, PM10) Quantity surveyor 8 Interviewees (QS1, QS2, QS3, QS4, QS6, QS7, QS8, QS10) Sub-contractor 10 Interviewees (SC1 – SC10)

Table 5.32: Project characteristics

Project characteristics Project code Project type Project location S1 Religious Ikoyi S2 Residential Ajah S3 Commercial Victoria Island S4 Residential Ikoyi S5 Commercial Lekki S6 Religious Yaba S7 Residential Ipaja S8 Recreation/Entertainment Ikeja S9 Mixed (Commercial and Recreation) Ikeja S10 Commercial Ikoyi

Figure 5.8: Map of Lagos showing project location marked in red Source: Adapted from Lagos (n.d.)

186

5.2.2 Process of Data Analysis As per section 5.2, a total of 65 semi-structured face-to-face interviews were conducted using the protocol provided in Appendix I. Interviews were recorded, transcribed, and uploaded to NVivo 11 QDA software for thematic analysis and for data organisation and coding. Themes were developed from the data, while codes were used to identify data that corresponded to each theme. Several sub-themes were also developed to identify trends, meaningful connections, and relationships as highlighted by interviewees. Overall, all codes, categories and themes are described in the analysis section below.

5.2.3 Analysis of Primary Data RQ1. What are the types, causes, and disposal methods of material waste in the Nigerian building construction industry?

5.2.3.1 Types of Material Waste Interviewees were asked to identify specific types of material waste produced on their projects. The following (See Figure 5.9, 5.10, and 5.11) were identified: i. Gypsum plaster (popularly called Plaster of Paris) ii. Cement iii. Timber and wood iv. Formwork v. Excavation (Earth materials) vi. Offcuts of reinforcement bars, ceramic or vitrified tiles and wood vii. Packaging materials such as cartons and plastic bags (popularly called Nylon in Nigeria) viii. Concrete ix. Aggregates (Sand and Granite) x. Dusts

Excerpts from the interviews show that offcuts of tiles and wood are generated in large quantities on most construction sites. One of the interviewees confirmed this, saying: “We are not at the finishing stage where there will be a lot of waste from tiling but even when we did the model room, we generated a lot of waste from offcut of tiles which you can see everywhere on the site” (PM8).

187

The responses of other interviewees highlighted the various types of material waste generated on their sites. Worthy of note among them is ‘dust’ as described by one of the interviewees: “we generate a lot of dust from drilling” (SC5).

Figure 5.9: Picture of wood waste on S7 Source: Author’s field survey (2017)

Figure 5.10: Picture of cement packaging waste on S6 Source: Author’s field survey (2017)

Figure 5.11: Picture of wood waste on S6 Source: Author’s field survey (2017)

188

5.2.3.2 Causes of Material Waste In response to questions about the causes of waste, responses that emerged were categorised as site management, site operation, transportation, procurement, natural hazards, and material handling and usage (see Table 5.33 for the complete list). One third of the interviewees were of the opinion that poor site management contributes to material waste. Site management deals with the organisation of site activities, including supervision (Figure 5.12). One of the interviewees was clear that “the reason for material wastage is poor supervision” (A7). Another reiterated that: “Sometimes the supervision from the engineers or foreman is not adequate. When you don’t supervise these workmen and artisans, you tend to generate a lot of waste” (E4).

Table 5.33: Causes of material waste

Sub topic Themes Sub themes Number of mentions Design Building shape 5 Design error 7 Design changes 9 Specification error 2 Procurement Variation 4 Material surplus 10 Substandard materials 7 Material inadequacy 1 Material packaging 6 Material handling Poor storage 4

and usage Poor material usage 4

age Transportation Bad road network 1 Site management Poor supervision 15 Poor management/planning 6 Site operations Poor construction 7 Construction methodology (e.g. cast- 5 in-situ) Site layout 1 Technology 2 Rework/Abortive works 4 Causes of material wast Human activities Inaccuracy of workers 8 Bad or poor workmanship 7 Level of experience 3 Level of skilled workers 4 Errors in measurement 3 Nonchalant attitude 7 Accident 1 Miscommunication 1 Corruption 1 Professional know-how 1 Natural hazard Hazard 1

189

Hazard Professional know-how Corruption Miscommunication Accident Nonchalant attitude Errors in measurement Level of skilled workers Level of experience Bad or poor workmanship Inaccuracy of workers Rework/Abortive works Technology Site layout Construction methodology (e.g. cast-in-situ) Poor construction Poor management/planning Poor supervision Bad road network

Causes of materialof Causes wastage Poor material usage Poor storage Material packaging Material inadequacy Substandard materials Material surplus Variation Specification error Design changes Design error Building shape 0 2 4 6 8 10 12 14 16 Number of mentions

Figure 5.12: Graphical representation of the causes of waste

A cross section of interviewees (main contractors, foremen, engineers, quantity surveyors and sub-contractors) were of the opinion that “changes in design” generate a lot of waste. Design, in the context of the interviews, refers to the building shape, spatial arrangement, and structural elements. One of the interviewees described how the shape of a structure caused material waste. He said:

“The oval shape brought about some material wastages in terms of tiles at the perimeter. In terms of laying those tiles there, it was difficult and the moment you cut 600X600m tiles, and it breaks, that is the end. The oval shape end generated a lot of material waste” (A10). The response of one of the interviewees about the causes of material waste was succinct. He said “the cause of material wastage come basically from design” (A8). Another interviewee further revealed that “the major causes of material waste could be change in design” (E10). In

190 addition, she suggested that: “…most often, architectural design tends to over emphasise aesthetics above the economy and that generates its own waste” (E10).

Other causes of material waste categorised under procurement include: material surplus, substandard materials, variation, inadequacy of materials, and over-ordered materials (Table 5.33). One of the interviewees reported that they generated waste as a result of suppliers’ negligence. He noted that some materials with defects were included in a large supply, which were only discovered at the point of use. The role of material manufacturers as it concerns the production of substandard materials resulting in waste generation was mentioned by one of the interviewees. He explained that: “The manufacturers or producers of the plywood told us that the plywood can be reused up to 5 times. But on this site, we used them twice and we could not use them again because they have reached their limit. As a result, those plywood became a waste. So, we were unable to use them to their full lifespan” (PM3). Over-ordered materials could lead to an unwanted surplus. Interviewees were of the opinion that excess materials are waste because they have no use for them. For example, one of the interviewees summarised his ordeal while dealing with excess concrete: “The wet concrete I ordered was so much that the leftover became a big problem to deal with on the site. Eventually, we used them to fill pot holes on the roads” (MC3).

Nearly two thirds of the interviewees observed human activities as a major cause of waste. Human activities are actions and inactions of construction professionals and operatives that result in material wastes. As noted by some of the interviewees, these actions include poor workmanship, errors in measurement, and miscommunication. For example, one of the interviewees was clear about how errors in measurement resulted in material waste, saying “…it resulted from inaccuracy of the workers due to some errors in measurements” (A3). Another interviewee observed that“…the quality of the workmen, their level of expertise, their technical know-how and their experience level also affect waste generated” (QS4). Similarly, miscommunication between professionals was flagged as one of the causes of waste. The passivity of personnel on site were identified as nonchalant attitudes, lackadaisical attitudes, and negligence. These are carefree attitudes lacking pro-active measures to save material waste. For example, one of the interviewees emphasised that:

“…the cause of material wastage on this particular site is just from the labourers. The way they handle materials, their lackadaisical attitudes, I don’t care or lack of concentration” (F3).

191

Some interviewees observed that the cause of material waste “is [the] nonchalant attitude of some operatives” (E5). This was supported by one interviewee, who said that “there are some percentages caused by negligence. Most of the waste in the construction industry [is] not accrued to negligence” (PM9). Also of concern was the “lackadaisical attitude of artisans” (QS7) and manual handling by operatives, as indicated by one of the interviewees: “It results from handling by masons in the process of rushing to finish off their tasks for the day” (MC9). Discussions also revolved around construction methodologies and techniques, site layout, and abortive works. Less than one tenth of the interviewees (QS2, QS4 and A6) agreed that the construction methodologies and techniques adopted on their various project sites caused material wastage. One of the interviewees confirmed that: “the major cause for now is that most of the casting we do, [is] done ‘in-situ’” (PM4). Improper site layout was cited by some of the interviewees as one of the causes of waste. Another interviewee described improper site layout as: “…the contractors’ utilisation of site, that is, how the site was organised generated material wastages” (QS1). Other causes of waste categorised as site operations are rework and abortive works. One of the interviewees described how rework caused waste. He said:

“Rework – if someone makes a blunder for example, we do cube test and stability test of the concrete. If one column, for example, fails the test, that column will be demolished. When that is done, an avoidable waste has been generated” (A9). With respect to ‘procurement’, nearly half of the interviewees agreed that material packaging is detrimental to the construction industry because it constitutes a nuisance on project sites. Some of the interviewees decried the effect of material packaging on their project sites. For example, one of them recapped:

“Basically, most of the materials that we bought were packaged with one stuff or the other which generates a lot of waste after we have used the product because we still have to do away with the packaging material” (SC7). According to some interviewees, improper handling and poor usage of materials generated a lot of waste. In this context, improper handling refers to poor control, distribution, and storage of materials. One of the interviewees revealed: “In terms of our handling of materials, we have generated a lot of waste from there…it has to do with our inadequate storage system on site” (QS2). Similarly, another interviewee identified an improper storage system for material on his site. He stated that: “…we do not have proper storage facilities on this site. Some of our materials are kept in the open and, as a result, we have generated so much waste” (PM2).

192

Overall, the main cause of material waste in the Nigerian building construction industry, as shown in Figure 5.12, is poor supervision, based on the number of times it was mentioned by multiple interviewees (Table 5.33).

5.2.3.3 Construction Material Waste Disposal Interviewees were asked about their disposal methods, and their responses highlighted a number of methods (see Table 5.34), ranging from ‘cart away’ to burning. The analysis (see Figure 5.13) revealed that the most adopted method was ‘cart away’ by government agency. This method of disposal involves dumping waste in a designated spot on site for onward collection by a government agency, as revealed during the interviews:

“One of our waste disposal methods is to use the government agency which is owned by Lagos State Government. Each time we have waste that we need to dispose off the site, we normally call them to come over and take them away” (QS2). The interviewees who stated ‘cart away’ were asked if they knew the end point of such waste. It was clear from their responses that most of them did not know but assumed proper handling by the government agency. Here is a comment from one of the interviewees:

“No, I don’t. I assume the Lagos State Government has procedures and processes in disposing waste appropriately. We leave that to the Lagos State Government to deal with. We don’t dispose of them ourselves, we get the agency to dispose of it” (PM2). Table 5.34: Waste disposal methods

Disposal method A E F MC PM QS SC Total Cart away by 3 4 3 5 4 2 4 25 LAWMA Open dumping 2 3 1 4 3 13 Re-sell 1 1 2 1 2 1 1 9 Burn 1 1 3 1 1 1 8 Reuse 1 2 3 1 7 Give out 1 1 1 1 3 7 Unsure 1 1 2 4 A –Architects, E – Engineers, F – Foremen, MC – Main Contractors, PM – Project Managers, QS – Quantity Surveyors, SC – Sub –Contractors, Figures – number of mentions

193

Throw away

Give out

Burn

Reuse

Re-sell Disposal methods Disposal Cart away by LAWMA

Unsure

0 5 10 15 20 25 30 Counts

Figure 5.13: Graphical representation of waste disposal methods Construction waste collected from various sites by the government agency is sent to landfill. Similarly, one of the interviewees also confirmed the non-availability of control tips in Lagos. He said:

“In Lagos state, there is no control tip anywhere. I know this because I was involved in drafting the policy of asbestos for the state government and there is no control layer where you can drop asbestos or anything. There is no control tip” (PM8). From the interviews, it is evident that burning of material waste is still predominant in the NCI (see Figure 5.14). Less than one fifth of the interviewees were brave enough to say that they burn waste, knowing fully well that it is not a safe practice. It causes air pollution, depletes the ozone layer, and above all, there is a state legislation against open air burning. Interestingly, some of the interviewees were aware of the legislation and the environmental effect of burning, but this did not inform their actions. For example, one of them noted: “There are some that we burn even though there is a State legislation against that” (MC1). Another interviewee indicated that: “Sometimes we burn the waste, which is against the law, because we don’t have a choice [other] than to burn them. Although, it causes air pollution” (F5). On the other hand, some of the interviewees are not aware of the effects of open air burning and, as such, they could not see anything wrong with it. They do it as part of their construction activities. For example;

“Most times when we see that the wastes are too much and we can’t get anybody to take them out of site and we know that we need to get them off. Well, good enough, wood or timber for what they are, they can get easily consumed by fire. We just pack them together and stack them somewhere then we burn them off” (MC7).

194

Figure 5.14: Picture showing evidence of burning on S7 Source: Author’s field survey, 2017

Less than one tenth of the interviewees revealed how they reused material waste. It is obvious from their comments that waste was reused on the same or on another site. Sometimes, waste was given to whoever needed it, while some could be used as backfills. Here is a sample of their comments:

“What we do is to get people that need such material to come and take them off the site for it not to be an issue for us on the site. The ones that we know fully well that we don’t need at all and nobody needs it, we will pack them together for disposal. But for others that we know it’s useful to people, we get people that need them to come take them out” (QS7). Some of the interviewees reported making economic gains from material wastes. They sold it to people who needed it for whatever purposes. One of the interviewees revealed:

“Yea, disposal of material waste in this part of the world is very expensive. So, most time what we do is to sell some of the fossil materials that we know we can’t reuse. We sell them or even give them out to people who use them as fossil fuels” (E7). The nonchalant attitude of some project players was evident in their responses when asked about how material wastes are disposed of on their sites. It was clear that they have no idea of waste disposal methods and, as such, they swiftly shifted the responsibility to the main contractor. One of their responses is illustrated in the following extract:

“The main contractor is responsible for the disposal of all wastes even if it is generated by the sub-contractor as long as it is within the control area of the site, the main contractor is responsible for removing it on site on a daily or weekly basis” (PM8).

195

RQ2. What are the attitudes, awareness, and perceptions about construction waste minimisation by Nigerian building construction firms? 5.2.3.4 Awareness of the Effects of Material Waste The interviewees demonstrated a high level of awareness of the effects of material waste on their projects. Their responses were categorised into six themes, namely: cost, time, environment, character, safety, and project effects (see Table 5.35). As shown in Figure 5.15, nearly two thirds of the interviewees revealed that material waste affects the project cost. For example, one of the interviewees noted:

“The effects mostly would be channelled to the monetary aspect of it because that is where everything happens. We all say okay, let’s minimise waste so that we can make profit and not losses. That is just majorly the effect” (E10). Consequently, the effects of material waste on project duration were identified by some of the interviewees. One interviewee said: “…it affects time of delivery of this project” (MC1). Another revealed that: “it extended our delivery time because labour was lost in the process of waste disposal” (E8). One of the interviewees provided a detailed account of how material waste has affected his project. He said:

“It slows down progress in different ways. One, the program is affected due to such delays. Movement on site becomes a problem when there are stacks of waste in different places. For example, it will be difficult for tractors and vehicles to move around. It causes friction and that leads to time delay which is very critical” (A9). Table 5.35: Effects of material waste

Sub Themes Sub themes A E F MC PM QS SC Total topic Cost Cost overrun 6 5 4 7 5 7 3 37 Time Time overrun 1 1 2 2 6

Time delay 1 2 1 2 6 Character Psyche of project players 1 1 2 Psychological effects 1 1 Company’s image 1 1 1 3 Clients’ unwillingness to 1 1 pay Environment Hazard/Release of toxics 2 1 1 1 5 Litters the environment 1 1 1 1 2 6 Safety Injury 1 1 1 1 1 5 Effects of material waste material of Effects Hinders movement 2 2 Project Bad work 1 1 Unkempt/dirty site 1 1 1 1 1 1 6 A –Architects, E – Engineers, F – Foremen, MC – Main Contractors, PM – Project Managers, QS – Quantity Surveyors, SC – Sub –Contractors

196

Unkempt/dirty site Bad work Hinders movement Injury Litters the environment Hazard/Release of toxics Clients’ unwillingness to pay Company’s image Psychological effects Psychic of project players Effects of materialEffects of waste Time delay Time overrun Cost overrun

0 5 10 15 20 25 30 35 40 Number of counts

Figure 5.15: Graphical representation of the effects of material waste Conversely, one of the interviewees revealed that material waste has not really affected the delivery time of his project but has caused cost overrun: “…it caused time overrun on this project. For example, when you generate a lot of waste, like when you do rework, it could cause time overrun. The major one that is impacting on this project now is cost overrun” (QS10). The effects of material wastes on the environment, character, and safety of project players were identified by some of the interviewees. For example, one of them said: “Waste affects the psyche of project players and it diminishes the integrity of the construction company in the sight of the client” (A4). Another interviewee noted that: “…when you generate such wastes and you are not moving them out of site on time, it can lead to hazards such as [a] fire incident, which we encountered [a] few times on this project because of the terrain where we are” (PM7). In addition, another interviewee observed that material waste not only affects the project, but also the construction company. He stated that: “It affects the project players; it affects the cost of the project. It affects the profit of the construction company. It also diminishes the integrity of the construction company in the sight of the client. In addition, it translates to clients not willing to pay professional fees” (A4).

5.2.3.5 Attitude of the NBCFs to Waste Minimisation Attitude is “a relatively enduring organisation of beliefs, feelings, and behavioural tendencies towards socially significant objects, groups, events or symbols” (Hogg & Vaughan, 2005, p 150). In this study, interviewees’ attitudes were assessed based on their responses to the

197

questions posed to them. The analysis of their responses is described as positive, neutral, and negative (see Table 5.36 and Figure 5.16). A positive attitude in this context refers to being proactive and always looking for solutions to challenges. A neutral attitude is interpreted as being neither active nor inactive, while a negative attitude is a carefree attitude and the feeling of not being interested in solutions but rather shifting responsibilities to someone else.

Table 5.36: Perception of the NBCFs on the importance of waste minimisation

Project goals A E F MC PM QS SC Total Cost/Profit 9 8 6 8 8 8 7 54 Quality 1 2 1 1 1 3 9 Safety 1 1 1 1 2 6 Environment 1 1 1 2 5 Health 3 1 4 Time 1 1 1 3 A –Architects, E – Engineers, F – Foremen, MC – Main Contractors, PM – Project Managers, QS – Quantity Surveyors, SC – Sub –Contractors

As shown in Table 5.36, more than four fifths of the interviewees exhibited positive attitudes towards waste minimisation. The majority take actions immediately they see waste on site and where possible, reduce waste before it is generated. One of the interviewees stated that: “Whatever waste we generate, I ensure they are properly disposed as soon as we finish for the day. I tell the guys to pick up the wastes, put them in the bin and take them out” (SC1). Similarly, another interviewee described his actions:

“I take the issue of waste very serious especially cement slurry. There is a standard policy of the company, which is inside organisation standard procedure (OSP). For every project we are in, there are ways we manage our waste and that is where the issue of salvaging some items come in” (QS8). Nearly one fifth of the interviewees displayed negative attitudes to waste minimisation. For example, one of them stated that: “Since we are not the one generating the waste, we don’t particularly have much to do with managing it, except if it becomes a problem on the site” (E1). Similarly, another interviewee stated that he is only interested in reusable waste: “If they are not reusable, there is nothing that I can do about them” (F2). Other interviewees expressed their feelings about decision making on waste minimisation. They feel it is the main contractor’s responsibility and, as such, they do not have interest. As noted by one of them: “It is the sole responsibility of the main contractor” (E3).

Figure 5.16 reveals that nearly all main contractors had a positive attitude towards material waste minimisation, while half of the foremen exhibited a negative attitude. Similarly, three

198 quarter of sub-contractors and engineers displayed positive attitudes while less than two thirds of architects and quantity surveyors, and less than half of project managers were indecisive.

10 9 8 9 7 6 7 5 6 4 5 5 3 4 4 4 2 3 3 1 2 2 2 1 1 1 1 0 1 1 1 0 Architect Engineers Foremen Main Project Quantity Sub contractors contractors managers surveyors

Negative Neutral Positive

Figure 5.16: Graphical representation of interviewees’ attitudes to waste minimisation

5.2.3.6 Perceptions of the NBCFs on Material Waste Minimisation To determine the perceptions of the NBCFs to material waste minimisation, interviewees were asked about the importance of minimising material waste. More than four fifths of the interviewees perceived cost in terms of profits as the most important factor for minimising material wastage. According to some of the interviewees, they ensure maximum profit by not exceeding the budget through minimisation of material wastes. One of the interviewees revealed:

“First and foremost, the importance of material minimisation is about the cost implications. It is very important. We have to make sure we drive down waste generation to the lowest level possible and we don’t want to incur cost in any project beyond what is budgeted for” (SC9).

Another interviewee perceived that poor material waste minimisation is tantamount to profit loss. He stated that his company ensures judicious use of materials to avoid wastages: “On this site, we exercise the regime of zero tolerance for waste because if it goes uncontrolled and without checking, I tell you, it will affect our bottom line. It will affect our profit margin” (PM7).

Similarly, one of the interviewees observed that his company is struggling with material waste minimisation but perceived that effective material waste minimisation would increase the company’s profit. He said:

199

“To minimise material wastage is very important because everything is about money. On every project, we normally allow 5–10% for wastage. By the time we exceed that, we are already spending into our project money. I think it is high time we looked into that so as to make some profit” (E10).

Notably, one of the professionals claimed that he is not an environmentalist, and only engages in construction for monetary gains. He said: “Yea, it is about the profit because I am not an environmentalist. I am here to make profits” (E4).

By way of contrast, less than one fifth of the interviewees perceived the quality of a project to be the most important factor for minimising material waste. One of them revealed that: “We provide quality construction for our clients at a minimal cost. In other words, we get them quality construction with less material waste generated” (PM5). Some other interviewees perceived a number of factors, including health, environment, safety, and time, as important factors for minimising material waste. Figure 5.17 reveals the analysis of their responses. In the order of preference, safety was perceived next to quality and cost while environment was next to safety. The least perceived factor was time. One of the interviewees discussed why he considered the environment as important for minimising material waste. He said: “From the environment aspect, it is important because most of the materials that are been depleted are not renewable.” (A4).

Quality

Time

Safety

Environment Project goals Project Cost/Profit

Health

0 10 20 30 40 50 60 Number of counts

Figure 5.17: Graphical representation of NBCFs’ perception of waste minimisation

RQ3. What are the current approaches adopted by NBCFs to minimise material waste at design, procurement and construction phases? 5.2.3.7 Design Approaches Implemented in Practice by NBCFs Design approaches are measures adopted to minimise material waste at the design phase. A range of views about such design approaches were expressed by the interviewees. For example,

200

it was identified that specifying locally available materials will ensure material waste minimisation:

“One of the decisions I took when I was doing the design was that all materials to be used must be procured locally. Two, I tried to make sure that my material specifications for tiles, ceilings are along the region of what is in the market – 300 X 300mm, 600 X 600mm etc. by so doing, I have reduced waste on site” (A1).

Another interviewee identified collaboration and communication with other design team members. He noted that through effective communication, they were able to decide the most appropriate design strategy in minimising material waste. The following quote illustrates: “We had to minimise the curvature in the design, we worked in conjunction with the structural engineers in terms of the grids, and layout of columns’ positions. In certain situations, when we had to deal with circular columns, the architect, structural engineer and the contractor had a round table discussion on fabricating steel formworks and that worked out” (A6).

Similarly, one of the interviewees emphasised that communication with other design professionals helped reduce material waste. He said:

“I think, on this project, we have achieved 90–95% waste minimisation. We have worked hand in hand with the architect and the consultant on this project. We have been working round the clock to make sure that design is properly done before implementation. Although we have had a couple of issues – but they are minimal and we resolved them easily” (SC9).

Three quarter of the interviewees identified simplification of the building form as an effective design approach to reduce waste. They imply that buildings with complicated forms (e.g. curves, corners, and circles), which are associated with contemporary styles of architecture, would generate waste, but regularly shaped buildings would minimise waste. Here is a sample of their comments: “We eliminated those aspects of the design where we tend to have gurgles that will lead to waste of materials. We do not have roof gutters and curved roofs. Our design is straightforward, easy to understand. So, that has really helped in the ratio of waste generated on this project” (PM7).

Another design approach identified by two thirds of the interviewees was uniformity in design spaces. This implies consistency across room sizes, floor to ceiling height, and material sizes. According to the interviewees, uniformity will encourage off-site prefabrication of materials, which will contribute to waste minimisation. The following quote illustrates one of the interviewees’ opinions:

201

“What we have here is similar floors and all the blocks of building that we have here are prototypes. That is a waste-minimising design on its own, because we can move materials that we have used for a previous floor to the next, just like cut and paste on the computer” (E7). In another response, modular construction was identified, as the following quote shows: “In order for us not to have material wastage, which is from sandcrete material (i.e. block, cement and concrete). We actually made the place to have less … sandcrete block and more … framed structure (beam and column). By the time the construction is done with, we will have less material to dispose. And also, we would encourage the would- be occupants not to use sandcrete materials for partitioning, but frame-based partitioning materials” (M5). Less than one fifth of the interviewees have adopted prefabrication, or off-site manufacturing of building elements, on their sites. They described it as an effective approach to minimising material waste if recommended in the design. One of the interviewees revealed that:

“We prefabricated a couple of things off site based on the design recommendations. We went to the site, took measurement, prefabricate, and then install them. This has reduced a lot of waste on the site” (PM4). Less than one tenth of the interviewees also disclosed that they considered the reuse potential of materials during the design of their buildings. They ensured that reusable construction materials, such as plywood, were specified. One of the interviewees noted that: “Based on the design, the length of reinforcements were done in such a way that even if there are offcuts from column reinforcement, we can use them for lintels. From the structural design, reinforcement bars were designed such that there are places we can reuse them. For the architect, when it comes to the aesthetic part of the project, he has provided ways to reuse some materials e.g. blockworks. The partitioning also allowed for minimum wastage of materials” (F1). Consideration of maintenance of services through design review was identified as a design approach that minimises material waste. As described by the interviewees, it ensures that adequate spaces are provided for building services requiring routine maintenance. This is done through a series of design reviews with the design team. One of the interviewees disclosed: “Lately, when we do our design, we look at it through design review and we are able to identify where waste will be generated. Through design reviews, we have been able to judiciously do our design[s] in such a way that they are compact and no amount of waste [is] generated” (A10).

Yet another interviewee revealed that he considers material logistics during the design. These deal with the management of materials, including transportation, safety, and storage. One of the interviewees revealed that adequate consideration for materials will minimise waste. He said: 202

“We already know where the materials are going before mobilisation. It was quite easy for us to bring all our materials and items to site, and I think it has actually reduced waste” (F3).

In contrast, more than half of the interviewees admitted that material waste minimisation was never considered during the design. Rather the focus was on aesthetics, quality, profit, strength, stability, and functionality. The following is a sample of their responses:

“Waste was not a consideration when we started. We were more concerned or focused on giving the client what he wanted. So, we didn’t focus on waste as a parameter in this design. The design has not been able to reduce waste; probably it has generated waste” (MC4).

Similarly, another interviewee noted in his comments that the traditional method of construction, which encourages casting concrete in-situ, generated a lot of waste. He said:

“I think if the design has inculcated using a prefabrication system, the wastage would have been drastically reduced, but what we are doing here is purely in-situ. If we have opted for a prefab where the components are brought from a yard and coupled together on a portal frame, the waste would have been reduced. Based on that, waste was not part of the planning” (QS8).

5.2.3.8 Procurement Approaches Implemented by NBCFs The key question was whether the procurement approaches adopted were able to reduce material waste. The findings indicated that two thirds of the interviewees agreed that their procurement approaches had a significant impact on reducing waste on their sites. For example, one of the interviewees revealed that he adopted “just-in-time” delivery of materials. This approach ensured that materials were delivered to the site when they were needed to avoid lengthy storage that could result in wastage. He said: “I think we were smart enough to delay things that were not needed initially, or at a particular point in time, to a good time where we procured them. They stay for a very short period on site and we use them. We didn’t store them over a period of time so that temperature changes, or sun or human activities will not affect them, so that they do not become waste. In terms of that, we have done well for procurement to ensure that things don’t get wasted” (MC1). For another interviewee, the ‘just-in-time’ approach was accidental on his site but proved to be effective. He said: “Materials were procured late and, as such, they were not stacked for too long before being used on site. It is just a kind of just-in-time delivery. Unfortunately for this project, just in time was accidental but it has helped in reducing the waste” (A9).

203

Yet, another interviewee noted that the ‘just-in-time’ approach was adopted because they lacked storage facilities for materials. He reiterated: “I think the method or approach we adopted is reasonable because we don’t even have space for storage. The approach is like – we bring at a time what is needed because there is no place to haul any material… The method has been able to reduce waste considerably” (E6). More than half of the interviewees revealed that their procurement approaches involved examining the need for the material before purchase. This implies that materials were procured only when the need became evident and, as such, it minimised waste. The following quote illustrates some of their responses: “We make sure that the materials needed are what [has] to be brought to site. We make sure that we don’t bring materials to site in excess that, at the end, we might not use them… When we are buying ready mixed concrete, we make sure we know the exact cubic metre that we need. We can’t have left over because it cannot be returned” (F8). One third of the interviewees indicated that their procurement approach was to purchase materials from local suppliers, especially those they have had a relationship with over time. They trusted them to supply quality materials. One of the interviewees recalled: “We have registered suppliers that work with us. Whenever we need materials, we will raise material requisition to the office with the quantity we need and they will get them from those suppliers” (E4).

One of the interviewees echoed this, saying that lobbying for contracts by local suppliers could cause a massive wastage of materials. Lobbying is a common practice in the NCI and could be politically motivated. Both experienced and inexperienced suppliers are involved in this act. Material waste could be generated through supply of substandard materials by inexperienced suppliers. One of the interviewees explained: “Procurement in Nigeria is a big challenge because we have what we call “jiggery pokery” – people are not straightforward. Procurement is supposed to be straightforward, but you will find people lobbying for their materials to be used on site. Sometimes they could bring sub-standard materials because the supplier has lobbied to supply materials to be used, and in that case it will always be waste because you are procuring substandard materials” (PM2). On the flip side, another interviewee revealed that his firm buys materials from companies overseas because they trust that these products were made with quality materials and, as such, waste would be reduced. The following extract indicates the interviewee’s comment: “We procure most of our materials from abroad. I believe it is better because we are sure of what we are getting. They are foreign companies and not local companies whose source of materials we don’t know” (QS10).

204

More than half of the interviewees also revealed that their procurement approach was to purchase durable materials. According to them, high quality materials would ensure waste minimisation because they wouldn’t be replaced frequently, unlike poor quality materials: “On procurement, our approach is to go for quality. We buy quality materials because we usually enquire for the most competitive in term of cost and appropriate stock checking” (M6).

Nearly two thirds of the interviewees revealed that they buy in bulk to avoid material wastages. This is done mostly on sites with adequate storage facilities and to avoid desperate procurement of materials during construction, which could result in the supply of substandard materials. The following quote illustrates some of their comments: “We procure materials before the job even starts or before the foundation of the building. We buy, like, 60% of the materials because we have a store room where they are all kept. Each of the materials are well positioned in the store room” (SC4).

One of the interviewees indicated that underestimating the number of materials has helped in reducing material wastage. Underestimation, as adopted on the interviewee’s project, involved the supply of fewer materials than budgeted for. This compelled operatives to manage these materials. According to the interviewee, the approach has been effective in minimising waste: “What we do is that we underestimate instead of the common overestimation. We underestimated a bit so that we do not have surplus materials and that has helped to reduce waste” (MC3).

Conversely, more than one third of the interviewees revealed that their procurement approaches had generated more waste rather than reduced it. Others felt procurement had nothing to do with material waste. Here is a sample of their comments: “I don’t think procurement has anything to do with waste. It is what is needed that will be bought. It is whatever that gets to site that we pay for” (PM6).

5.2.3.9 Construction Approaches Implemented by NBCFs Interviewees were asked about the effectiveness of their construction approaches in minimising material waste. Notably, two third indicated that these did reduce material wastage. One of the approaches involved the use of excavated soil elsewhere on the same site. This is the transfer of earth from a section of the site to another. It could be used as backfilling or for other purposes deemed fit by the project team. One of the interviewees stated: “…where we could have wasted a lot of material on this site was the excavation, because what we excavated from the site was later used for backfilling. That would have been a major waste” (A6).

205

Less than three quarter of the interviewees revealed that they adopted the frame structure approach, which they considered to be effective in minimising material waste. The approach is a common construction technique where beams, columns, and slabs are joined to form a building’s skeleton framework. With the frame structure, formwork materials such as wood and off cuts of reinforcement bars can be reused, as revealed by one of the interviewees: “The method adopted is frame structure. What we did was that once the slabs were erected, we construct the columns. Once each floor is completed, we move on to the block works. It has reduced the amount of waste in the sense that we were able to identify that all the waste [was] rebar and formworks and we reused them” (PM9).

Another construction approach adopted by nearly one third of the interviewees was to identify construction activities that can reuse materials. That is, activities that generate waste were identified and avoided if possible. One of the interviewees explained this as follows:

“From experience, we know that wood formwork could generate a lot of waste. Instead, we decided to use of aluminium formwork which was quite a good method we adopted because it reduced waste” (A9).

Improved construction methods, such as ‘precast’, were identified by more than half of the interviewees as an effective method of reducing material waste. Structural members, especially those made of concrete, such as beams, columns and slabs, were produced on or off site before being placed in position. As such, the mould could be reused, and waste resulting from formwork, wet concrete, and de-propping were reduced, as noted by one of the interviewees: “What we have done here is to precast the elements and it has helped us to minimise cost. Not just cost, it has helped us to minimise waste. For example, if you cast in-situ using timber formwork, wastes may be generated due to the method of casting or human errors” (MC1).

Conversely, one of the interviewees highlighted a situation where prefabrication of material on site generated some waste. He said: “The mechanical, electrical and plumbing (MEP) generated a lot of waste on this site. During the installation of insulation materials into the ducting, which was fabricated on site, a high volume of waste was generated. Some of it [was] packaging materials” (PM8).

Although the majority of the interviewees revealed that they used the common traditional method of construction, there were mixed feelings about its effectiveness. Some argued that it was effective while others disagreed. The following quote highlights their varying opinions: “We did cast in-situ concrete, which is the most common method here. As a result, we generated a lot of waste when we were pouring concrete from foundation to the stage we are now” (QS10).

206

One other approach identified by the interviewees was effective team work. Less than half of the interviewees were of the opinion that teamwork would ensure waste was reduced as much as possible if all project actors played their part. One of the interviewees revealed that teamwork allowed for simulation even before actual construction. He said: “We sit back strategically with other team members to strategise and plan our work. We do something like simulation before we hit the site. The planning basically has helped us a lot to reduce material wastage. We plan our work even before we start anything on site” (E8).

On the flip side, less than one third of the interviewees noted that the construction approach adopted on their individual sites generated waste. They revealed what they could have done to minimise waste. One of the interviewees said: “Our construction method encouraged material wastage. If we had deployed the system whereby we used precast materials, it would have cut down the waste” (A4). Another interviewee noted that: “…if everything we used here [was] prefab off site, the waste would reduce drastically. We used our conventional method and of course with that, generation of waste is inevitable” (PM4).

In the same vein, one of the interviewees revealed that the problem of material waste was nationwide and not peculiar to his site. He said: “The common method of construction in Nigeria is the traditional method of construction. One of the things with Nigeria’s traditional method is that we use sandcrete blocks, and anywhere you use sandcrete block, there will always be waste” (MC5).

According to nearly two thirds of the interviewees, waste minimisation was not considered at the inception of their projects. They had no waste minimisation approach in place and, as a result, high volumes of waste were generated: “I don’t think material waste minimisation was in the big picture. Maybe we just had it at the back of our minds. It is not something that the team sat down to discuss, and that has really caused a lot of wastages” (E10).

Notable among interviewees’ comments was the improper documentation of their construction methodology. As noted by one of the interviewees, the procedures adopted in any construction methodology should be written in clear language to be understood by everyone. This could form part of the standard organisation procedure, which would help reduce material wastes. He said: “The challenge that we had is that some of these construction methodologies are not properly documented. They were spoken verbally. Now, for them to be effective, some

207

of them has to be documented and give to everybody on site to read through, else you will find people doing things the other way” (MC7).

RQ4. To what extent are the 3R principles being adopted by the Nigerian building construction firms? 5.2.3.10 The 3R Approaches Implemented by NBCFs The reuse, reduce, and recycling approaches are CE principles for waste minimisation. Interviewees were asked about the adoption of these principles on their projects. Their responses varied. As indicated by nearly two thirds, reuse of materials on and off site is a common practice by the NBCFs. More than three quarter of the interviewees identified timber products and reinforcement bars as the materials most frequently reused on their sites. One of them said: “…basically reuse is in formwork. We can’t use any other materials except tools. Formwork is the best we can reuse. To be able to break even in formwork, the number of uses we are able to get out of the materials matters. The more we are able to use it, the more it pays off. The other things are salvaged items from demolitions, salvaged items, like I said before, may be if you salvaged good doors, it may be reused on temporary structures like site offices, windows, things like that” (QS4).

Some of the interviewees also confirmed that some waste materials were reused off site, as stated in the following quote: “In terms of reuse, we have other available ongoing projects that those material waste[s] can actually be effective for, so we do take them down there. As you can see, we have some of our form work panels being removed from one project and after completing that project, we would take them to another project for reuse. In case we do not have any other project to take them to, we will take them to the site yard for safe keeping” (QS6).

The final destination for waste materials (timber and reinforcement bars) was probed. The responses of nearly three quarter of the interviewees indicated that waste timber products were used as firewood for cooking while reinforcement bars were sold. Some of the reinforcement bars are melted, reproduced, and sold back into the system by local steel companies. One of the interviewees explained: “What we do is to sell them for those that will reuse them. They reuse them mostly for cooking purpose or whatever” (A7). Other materials that were reused included off cuts of ceramic tiles, sandcrete blocks, and concrete. According to the interviewees, offcut ceramic tiles collected from different sites were reused by the locals on floors. The process is locally known as “Paladina” flooring. This type of floor comprises various sizes, colours, and designs of offcut tiles arranged on the floor in a non-uniform pattern (see Figure 5.18).

208

Figure 5.18: Paladina floor Source: Author’s field survey, 2017

Concrete waste was also reused, as mentioned by the interviewees. It was used to fill pot holes on the roads, and as foundation backfill or hollow fill, as the case may be. One of the interviewees emphatically stated that most waste materials on Nigerian construction sites were reused. He said: “In this country, I don’t think any material is a waste. They are meant for something extra. The moment you take them out of the site, some people are already waiting to take them and reuse them. Even the offcut of tiles are still being used in most domestic buildings. They are useful very well” (A3).

In contrast to the adoption of reuse approaches, less than one third of the interviewees admitted that they have never reused any material on their sites. Some cited organisational policy as the reason for their actions while others indicated that such materials were of less quality. One of the interviewees commented: “That will be a “no–no” because every material we have generated so far on this project as a waste cannot be reused on this site. It is not tolerated; it is not allowed” (A8). Another interviewee, however, provided a summary of an ideal approach to reuse of materials on sites. He said: “…most of the time when we have to reuse materials, there was a deliberate effort from the architect to tell them (labourers) what and where to use them. Ordinarily I believe that if it was a system where everybody has thought about reuse of materials, it becomes a plug and play and we know that if we can’t use this for that, we must have an alternative usage for that material” (A4).

In terms of recycling, all the interviewees except one indicated that there was no form of recycling on their sites and that they did not use recycled materials. The interviewees provided

209

some explanations as to why recycling of materials was yet to be adopted. Notable among them was the absence of organisational and/or governmental policy compelling them to do so. One of the interviewees revealed that: “For recycling on this project, there is no policy to back that and we have not done any form of recycling of material wastes” (F1). Another interviewee indicated that recycling of construction materials was uncommon in Nigeria. He said: “In terms of recycling, that is an area that has not taken its full course. Recycling is still very much nascent in this part of the world” (SC9). Similarly, another interviewee insisted that recycling is the responsibility of the government. He said: “Recycling must be first established by policy. First, government should take the lead in recycling of waste. In [the] construction industry alone, there are tonnes of waste that comes from sites. If the government takes that proactive step, say okay – why don’t we build an industry around construction waste management? If they take the lead, they will formulate policies and put in place laws and enabling conditions for all contractors. For example, if you generate a certain waste from your site (maybe within a tonne range, e.g. say you generate 100 tonnes of waste) take it to the government and you will be paid a certain amount because you have generated raw materials for another product or project. It is like a chain reaction, there should be a government policy around it” (MC1).

The reasons for refusing to recycle materials varied, but chief amongst them was that they were of less quality compared to new materials. The findings from the interviews indicated that the majority of interviewees understood the concept of recycling and its numerous advantages, however, they were yet to adopt it. One of the interviewees revealed: “We don’t recycle materials here. My understanding of recycle is that boards that are no longer fit for construction work, may be processed by converting them to dust for further use. I don’t think that has any impact for us. We have never thought about recycling here” (PM7).

Similarly, another interviewee noted: “I believe that every product can be recycled, no matter how bad it turns out after its use. On this site, we are just following the general standard of the construction industry in Nigeria as a whole, which, to an extent, does not incorporate recycling of materials” (SC6).

As expected, more than four fifths of the interviewees did not know what happened to their waste after disposal, whether it was recycled or landfilled. One of the interviewees revealed that: “We don’t recycle them. We take them to a designated point approved by the main contractor. We don’t know what they do with them thereafter” (SC5). In the same vein, another interviewee noted that: “The recycling process is not something we practice holistically. When we dispose, we are less concerned about what the third party does with the waste” (QS6).

210

In summary, the reuse of material in one form or the other is common among building construction firms in Nigeria. In particular, more than three quarter of the interviewees highlighted that material waste, especially timber products and reinforcement bars, were reused on site. Occasionally, concrete and sandcrete blocks were also reused on site, while other materials were used off site. Furthermore, waste materials were not recycled on site and such materials are not acquired. In one of the sites where recycling of materials was identified, materials were reportedly sent to a government agency for recycling. The end point of material wastes generated on most construction sites was unknown to more than four fifths of the interviewees.

RQ5. What policies or legislative measures are required for effective waste minimisation in the NCI?

5.2.3.11 Policies and Legislative Measures Several interviewees commented on appropriate policies and legislative measures for minimising waste. Their responses were categorised into policies, law and legislation, project players, and projects (see Table 5.37).

Table 5.37: Strategies for waste minimisation

Themes Strategies (sub themes) 1 Policies (Government Strong policies and Company) Adoption of Health Safety & Environment (HSE) policy Buy-in Incentives 2 Laws and legislation Government legislation Government monitoring Penalty or fine Coerciveness Strict laws 3 Project specific Appointment of waste pickers Appointment of waste manager Motivation Quality control Limit access to materials 4 Project players Network system Corporate social responsibility (CSR) Quality supervision 5 Best practices Appropriate decisions on waste Waste sorting 6 Network system Waste exchange

211

According to the interviewees, policies can be categorised into company or organisational policies and government policies. Strong company policies that encourage buy-ins and incentives were advocated by some interviewees. For example, one said that: “The first thing is to capture the mind of the operators, because if we don’t have a buy- in, they wouldn’t have it done. So, the management of the organisations must have the understanding and buy-in” (A1). The need for government policies was emphasised by three quarter of the interviewees. They were of the opinion that government’s involvement through strong policies would help reduce waste. Such policies should be easily understood and adopted by all project players, as the following quote illustrates: “I think it will be good if we have a policy statement on waste. The policy statement should capture all approaches to waste minimisation within the construction industry. The policy should be able to specify the different categories and types of waste, from the organic to inorganic types of waste. It should be able to establish properly what should be done to minimise types of waste and at what point in the construction process or period should waste generated be disposed of. It will be fantastic if we can have policies guiding such and it should be open, like a public document that everybody in the built environment can have access to and we implement properly” (PM7). Nearly one third of the interviewees supported incorporating construction waste management into the current Health, Safety and Environment (HSE) policy of the government. According to the interviewees, the HSE policy has been effective and could assist in minimising material waste. “Honestly, it’s by following the path of HSE policy that we have in Nigeria presently because it has been working seriously in Nigeria. There is no construction site in Nigeria where the HSE is not enforced. The HSE was gazetted by the government and there are departments that enforce it in all local authorities. Same thing should be done for construction wastes” (PM5).

Conversely, one of the interviewees revealed that, as much as new policies are desired to ensure waste minimisation, there is a need for policies to be strong and effective, as the following quote illustrates:

“Policy is something we need as we are growing as a nation because with all the pollution around the world, honestly Nigeria cannot be left behind. For now, our policies are still very weak and gradually we are hoping that in the years to come we will have policies that will be executed and exhibited…” (A1). Two thirds of the interviewees suggested that strict laws and legislation about waste on construction sites would ensure effective material usage, which could, in turn, reduce material waste. Others added that effective monitoring, enforcement, and encouragement where

212 possible would help to minimise material waste. As suggested by some of the interviewees, the introduction of penalties and fines for defaulters could instil discipline in project players and ensure minimisation of waste. One of the interviewees revealed that every project player needs to know the worth of materials and by so doing, they would care about them: “…we need to know the meaning, and the value of the materials we are using because if you don’t respect the value of these materials, we won’t care about them. From my experience, most of the employees don’t care about the material…the government has to put strict laws. That is the only way everyone will abide. So, it is something that needs to be forced upon everyone” (SC10).

As for project-specific strategies, less than half of the interviewees identified appointing waste pickers or a waste manager whose job description would encompass effective management of waste through collection, sorting, and proper disposal. For example, one of the interviewees explained what occurs on his site: “In terms of the waste itself, we have engaged two workers whose duty is to go round and pick up all wastes. I ensure that at the end of every business day, all the wastes are properly stacked somewhere for eventual evacuation” (A1).

One fifth of the interviewees suggested that material waste would be minimised when operatives’ access to materials was limited. This would curb operatives’ lackadaisical attitudes to materials and ensure they worked with the available materials, as noted by one of the interviewees: “It depends on the amount of materials you make accessible to the artisans. When you limit the access they have to material, I think it is the powerful strategy I know of” (F4). Similarly, some of the interviewees reiterated that ensuring quality and material control will guarantee waste minimisation, as indicated in the comment below: “I think we can still do more in terms of quality control and in terms of material count. Regular count of material on site will go a long way to give the project a very good touch at the end of the day. I think we can still do more in the industry in terms of updating our material base and also find applications that can make material count easier for us; thereby, it will always reduce the amount of waste on site in general” (SC6).

More than half of the interviewees identified some strategies that were related to the project players and their organisations. They suggested an efficient network system among project players, quality supervision, and community social responsibility by construction firms as possible ways of reducing material waste on building construction sites. Here is a sample of their comments: “What we do with concrete wastes is that we use them for our community social responsibility duties. We use them to fill up pot holes on the roads. With that, the wastage is effectively managed” (QS8).

213

One of the ways to minimise waste is to ensure that the waste generated was well catered for in terms of decisions and planning. Less than one fifth of the interviewees suggested that appropriate decisions on waste as well as sorting of waste would ensure effective minimisation and management of waste. One of the interviewees said: “I think that part of the strategies that can be implored is to expose people to practices that encourage decision[s] on waste on projects” (A4).

One of the interviewees, however, provided a summary of strategies that could be efficient in minimising material waste. He said: “According to McGregory theory, there are 3 ways of managing human beings. The first is persuasion, the second is motivation and the third is coercion. The second approach relates to financial (reward). The persuasion is – you will gather your workers and persuade them. You will say – please, don’t waste materials, you need to use them. The second one is motivation. You will motivate them by telling them that ‘this is what we have, this is what we want to use and this is what we must use. If you can manage it and make sure that we do not exceed this, we will motivate you and give you XYZ’. If the two systems (persuasion and motivation) fails, then you will use coercion. Coercion is a kind of system that enforces. For example, if you waste this material, you are going to pay for it and you will be liable for it. I think that is the appropriate way to manage them so that material wastes are reduced. In human management theory, [the] human being is the most difficult to manage” (MC6).

5.2.3.12 Waste Minimisation Implementation Methods Interviewees were asked about appropriate implementation methods for waste minimisation. The methods that emanated from their responses were categorised into six: training and education, policies, international cooperation, laws and legislation, organisation, and communication (see Table 5.38). More than three quarter of the interviewees identified training and education, which encompasses orientation, awareness, enlightenment and seminars, as the preferred appropriate method to use to implement waste minimisation. For example, one of the interviewees noted that:

“First of all, you have to train these people, because they are used to the systems that we have imbibed in them, and, for any change to come, there has to be reorientation and retraining for them to have a change of orientation about waste” (A4). According to other interviewees, implementation of waste minimisation strategies starts with the promulgation of laws and legislation by the government.

214

Table 5.38: Implementation methods for waste minimisation strategies

Themes Methods (sub-themes) 1 Training and education Encouragement Motivation Prep talk Toolbox talk Training Education Seminars Awareness Workshops or talk shows 2 Laws and Legislation Forced recycling Forced reuse Government actions Establish department of waste management Establish monitoring agency Effective monitoring 3 Policies (Government and Following the path of HSE Organisation) Penalty or fine 4 International cooperation Import ideas from developed countries 5 Communication Effective communication Visual awareness on site Transferable information 6 Organisation Appoint a waste manager Division of labour Employ qualified or skilled personnel Proper documentation Flexible design Proper planning Prepare framework or guideline Organisation or firm’s action Quality assurance and quality control

To ensure compliance, the interviewees suggested the establishment of a waste management department as well as monitoring agencies. Similarly, less than one quarter of the interviewees suggested that the government should embark on forced reuse and recycling. Here is a sample of their comments:

“…make waste minimisation a law. It has to become a law. An adage says: where there is no law, there is no sin. Once you know that there is a law to that regard, then everybody will abide by that law and by that rule” (SC7). Other implementation methods advocated by the interviewees were organisational and governmental policies. More than half of the interviewees noted that penalties and fines may be imposed by organisations as a deterrent to waste generation and the government may enact policies similar to the HSE. For example, one of the interviewees stated that:

215

“The best way to implement [a] waste minimisation strategy is to have proper documentation in terms of policy. It is either a written document, verbal or oral, having rules and regulations guiding it in case there is non-adherence to the instructions. There has to be a penalty, because if there is no penalty, the down-liners tend to take it with levity” (QS6). However, one interviewee disagreed, stating that policies can be compromised and, as such, they should be properly monitored and enforced. He said:

“Government policy will help, but that alone is not good enough. It has to be monitored, and you know what our enforcement history is like – it can be compromised. So, if you put government policy alone, nobody adheres to it. There is a government policy in Lagos in terms of safety, there is even a yellow book on safety. I doubt if anybody has seen it” (PM8). Similarly, another interviewee supported the idea of enforcing policies, as illustrated in the following quote:

“I think it is all about enforcement. When you get to a situation where you have policies on ground, not just on paper. You have it written. For example, you know HSE (safety policy), you get to site and you see everything written on the board. You have zero tolerance to wastage and you have penalties when you begin to waste material” (MC7). Two thirds of the interviewees commented on effective communication among all project players as an important implementation method in minimising waste. They suggested creating visual communication on site as well as providing transferable information. In addition, a change of orientation, especially in terms of referring to waste materials as resources, was suggested. Here is a sample of their comments:

“You need to put it in information that is transferable. Then comes imparting that information and, also, monitoring. So, if you have a construction management framework or guideline that is taught to everybody across the board, across the chain of the construction ladder, try [to] make it a culture by re-enforcing that on [a] regular basis. Also make sure that it is someone’s responsibility to monitor the effectiveness of that process” (MC4). Likewise, one of the interviewees suggested international cooperation through transfer of ideas from developed countries. He said:

“I know there are efforts by the academia to reduce and to cut down waste. Workers and key players in the construction industry should be exposed to those processes as much as possible. You can import these ideas from [the] developed world. Why not bring in what they do over there, dismantle it and let’s see how to imbibe it into our local content here” (A4).

216

Less than three quarter of the interviewees identified several organisational methods that they felt would ensure effective material waste minimisation. These include: division of labour, employing qualified and skilled personnel, flexibility in design, proper planning, and adoption of a framework or guideline on waste minimisation. For example, one of the interviewees revealed that:

“The solution is flexible design - take enough time to get your designs, study designs that are friendly to your environment, designs that are easily achievable considering the expertise available, considering the equipment available, and considering the materials available locally. All these have to be played in, then the best hands need to be brought on board” (QS4). In summary, all potential implementation methods are considered necessary and should follow effective guidelines, as suggested by one of the interviewees:

“It’s a combination of enforcement and training. If you train and you don’t enforce, nothing will come out of it. As humans, we can be careless because we are not bound by law. But if we are bounded by law to do certain things, we will surely do. We need to create awareness of whatever law is to put in place. People need to know what the law is meant for and its penalties. When these things are put in place, people will manage waste voluntarily, and those that do not want to comply will be dealt with by the law” (SC5).

5.2.3.13 Training Focus Since more than three quarter of the interviewees observed that the training and education of project players would be effective in minimising material waste, they were asked to indicate specific training that their organisations should provide. Table 5.39 reveals various training topics proposed by the interviewees. These have been categorised into construction process, technology, material, management, project players, and time, cost, and quality.

Table 5.39: Proposed training focus for construction firms

Themes Training (sub themes) 1 Construction process Lean construction Construction techniques How not to do construction Masonry Standard operating procedures Wood construction Steel construction 2 Technology Measurement Use of modern technology and equipment Available technology

217

Themes Training (sub themes) 3 Material Precision on material usage Reuse Recycling Prudence in material usage Consumable materials 4 Cost, time and quality Cost management Delivery Time management Quality control Effective ways to achieve good quality with minimal cost Procurement Scope and budget 5 Management Environmental management Site management Project planning Waste management Marketing Coordination Health safety and environment 6 Project players Reorientation Skill upgrade Professionalism Responsibility Sense of belonging Multi-tasking Supervision Manual handling Personal attitude Upgrading technical know-how Standard practice

As for the construction process category, more than two thirds of the interviewees suggested training on construction techniques, wood construction, steel construction, lean construction, masonry and standard operating practices. These focus on the appropriate way to achieve construction with minimal waste, as suggested by one of the interviewees:

“…you need to teach them construction process. The basic construction process, in other words; let everybody have the knowledge of what another person does and, by so doing, they will have better understanding. Even for an architect, he or she needs to know how to put things together, how to arrange, so that he/she can see what his/her product will look like at the end of the day. Also, construction management must teach issue of marketing, cost, management and what have you” (A1). Training on the use of available technology, modern technology, equipment, and measurement are important in building construction. Lack of technical know-how or inexperience with a particular item of equipment could result in waste. Therefore, training and re-training are

218 needed to avoid wastage, as suggested by one of the interviewees: “…every company to provide technical training for their workers, because new products and technology are available in the market daily” (SC10). Similarly, training on material handling, reuse of materials, recycling, and appropriate use of materials was proposed by some interviewees. For example, one of them noted: “Honestly, it’s the precision in material usage. If there is precision in material usage, there won’t be [a] need to factor in percentage waste of any material” (PM5). Another interviewee felt that, with adequate training, recycling of materials will be embraced. He said: “…maybe there are some things that we are not recycling here that are meant to be recycled. When we go for the training, we will have more knowledge about it” (SC8). Furthermore, one of the interviewees emphasised that training about recycling would not only benefit individuals, but organisations and societies as well. He said:

“I will rather talk about how we can recycle, because we need to think of how to transform our waste to wealth. If we can make money out of waste, then it’s another way to generate employment and wealth” (SC5). Nearly four fifths of the interviewees provided some suggestions for management training. Their responses cut across project management, planning, HSE, site management, environmental management, marketing, and waste management. For example, one described the importance of management as follows: “Management is the most important. It is about managing [a] resource. Human resources, material resource and everything now boils down to the financial part of the business” (A5). Another interviewee expressed his feelings about getting the value of materials used through effective waste management. He said:

“This aspect of waste management definitely has to be part of the training. This is very key in the construction industry. We want to make sure that we don’t just use materials and not get the real value for what we budgeted for” (SC9). Similarly, one of the interviewees revealed that he considered training on effective construction planning as the fulcrum of all construction activities. He said:

“I will consider majorly construction planning because for construction management, as I know well, planning is key. For you to be able to effectively deliver any construction project, you have to plan it effectively” (QS7). Training on effective management of time and cost as well as quality control were identified by more than half ofof the interviewees. One of them highlighted the type of training required for professionals and operatives. He said:

219

“For the workers/professionals, it will be about time management, quality control. For the artisans, waste management will come in, and time management too. Time management is actually very key” (PM4). More than one third of the interviewees emphasised effective cost control and time management by operatives. The need to achieve quality with minimal cost and waste was outlined by one of the interviewees, who said:

“…these days, we are looking for effective ways to achieve good results with minimal cost. I think that is why the whole world is talking about cleaner energy and the rest of them. So, our focus will be on how to achieve quality with minimal cost” (E3). Three quarter of the interviewees identified several training foci for project players. These include manual handling, supervision, skill upgrade, professionalism, reorientation, standard practice, and upgrading technical know-how, including the use of software such as BIM and building management system. Here is a sample of their comments:

“I want the company to really focus on waste management, proficiency of the artisans, because if your artisans are proficient, they will be effective and your waste will be reduced both in terms of time and human. I also want the company to implant more sense of belonging into the heart of the artisans. I will like that sense of belonging to come first, followed by waste management and proficiency of artisans last. Why I put sense of belong first is that, if there is sense of belonging, you will yearn to be proficient” (MC6). RQ6. Can a circular-economy-based waste minimisation framework be adapted for minimising construction waste in the Nigerian construction industry? 5.2.3.14 NBCFs’ Waste Minimisation Policy Interviewees were asked if their firms have any written policy or plan on waste minimisation. Figure 5.19 shows their responses for all categories of interviewees, which reveals that less than two thirds of building construction firms do not have a written plan or policy. For example, one of the interviewees noted:

“Hmmm…that is a good one. I can’t say precisely that there is something written but I know one way or the other when we generate waste, we find a way of disposing of them, but for written policy, I am not aware of that” (MC7). In the same vein, another interviewee revealed that: “As far as I am concerned, we don’t have any written document that guides our approach towards waste minimisation” (PM7). Yet, another interviewee revealed that: “Most of our policies are geared towards hazardous waste, but for construction waste minimisation, there is no clear-cut policy” (MC4).

220

6 6 6 5 5 5 4 4 4 4 4 3 3 3 3 3 3 2 2 2 1 1 1 1 1 0 0 0 Architects Engineers Foremen Main Project Quantity Sub contractors contractors managers surveyors

No Unsure Yes

Figure 5.19: Graphical representation of the availability of written plan or policy on construction waste minimisation On the other hand, more than one third of the interviewees claimed that their firms had a written plan or policy that guided their activities. One of them reveals:

“Sure, there are plans in place. My company has a waste management department that handles all the waste being generated from different sites. We are registered with some companies that dispose waste, which is being done on [a] weekly basis or monthly basis depending on the agreement or terms of contract with the company” (F2). Another interviewee, however, revealed that the policy on waste minimisation is a basic requirement for all contractors and a major requirement for project execution. He said:

“The policy is written before every contractor submits [a] work statement, and part of their work policy is how to minimise waste on site. It is written but comes majorly from contractors that we engage on any project. It is mandatory for them in the contract management for any contract” (A8). Similarly, one of the interviewees indicated that his firm had a written policy on construction waste minimisation and that he encouraged their contractors to adopt it. He also revealed that a section of the Nigerian building code discusses waste minimisation:

“Yea, we do have. That is why, probably, prior to this interview, I have shown how I try to get my contractors to have an HSE policy. Apart from that, I am also aware of it through the new building codes which is yet to be passed into law. Some of us who are senior practitioners are trying to introduce it to the industry by telling our contractors

221

that they should start to adopt some of the policy directions that are contained in that building codes” (A1). Less than one tenth of the interviewees were unsure of their firm’s written plan or policy on waste minimisation. For example, one of them said: “I might not be able to say yes or no to any written policy document. I can’t say what I don’t know” (E6).

The interviewees were asked if their organisations would adopt a new waste minimisation approach. The finding indicates that all of them are willing to adopt it only if it is effective.

5.2.4 Summary of Qualitative Interpretation of Results This section has provided a summary of the qualitative data analysis. Many of the findings were consistent with the quantitative data analysis. They revealed that the dominant type of waste emanates from offcuts of tiles, while other waste materials identified include packaging of materials, gypsum plaster, cement, timber and wood. The interviewees identified a wide range of causes, chief amongst them being poor supervision. The main disposal method was through the government agency, while some of the interviewees noted that they burn materials, resell them, and discard them. There is a high level of awareness of the effects of material waste, especially as it affects project costs. Similarly, interviewees showed positive attitudes towards waste. Furthermore, the findings showed that the NBCFs practiced a wide variety of design approaches to minimise material waste, including specifying locally available materials, prefabrication, design review, simplification of the building form, and collaboration with other design team members. Similarly, procurement approaches include just in time delivery, buying in bulk, underestimating, purchasing durable materials, and purchasing from local suppliers. As for construction approaches, these include adoption of framed structure, identifying activities that reuse materials, prefabrication, traditional methods of construction, and effective teamwork. However, some interviewees did not consider material wastes during construction.

The findings also revealed that timber products and reinforcement bars are mostly reused by the NBCFs. Some are sold to locals who will reuse them, while the majority of the interviewees do not know the final destination of their waste. Most of the interviewees demonstrated a good understanding of the concept of recycling but did not adopt it. Policies or legislative measures for minimising waste were identified to include organisational and government policies, laws and legislation, project players and best practices. In the same vein, implementation strategies were classified into training and education, laws and legislation, international cooperation, communication, and organisation. Training and education of project players and operatives was emphasised by most interviewees, who identified various training foci that were categorised

222

into construction process, technology, material, cost, time and quality, management, and project players. Lastly, more than half of the interviewees confirmed that their companies did not have a written policy or plans for construction waste minimisation. However, all interviewees observed that their firms would be willing to adopt new waste minimisation measures.

The following chapter synthesises the quantitative and qualitative data findings. The results are compared while identifying discrepant and congruent findings, which forms the basis for discussion. In addition, the circular economy waste minimisation framework is developed, based on key issues identified in the study, such as waste minimisation, behavioural factors, policy decisions, and enforcement/compliance.

223

CHAPTER SIX DISCUSSION 6.0 Overview The previous chapters (one to five) have discussed relevant aspects of the study leading to the discussion in chapter six. The research problems, gaps in literature, aims, objectives, and scope of the study were addressed in chapter one, while key concepts of sustainable development, including construction waste management, were reviewed in chapter two. Chapter three reviewed the circular economy concept and its potential for the construction industry, while chapter four provided a detailed methodology for the study. The outcomes of the investigation were presented in chapter five. This chapter (chapter six) discusses the study’s findings in light of the objectives presented in chapter one. It also synthesises findings from quantitative and qualitative data to inform the development of a circular economy waste minimisation framework for Nigeria. Construction material waste generation at the design, procurement, and construction phases, as well as the types of waste and waste disposal methods, are identified. Thereafter, the attitudes, awareness, and perceptions of waste minimisation based on company characteristics, including size, ownership status, and main construction activity, were discussed. The relationship between awareness, attitudes, and perceptions of the NBCFs forms part of the discussion. The chapter then reflects on the current waste minimisation approaches adopted by the NBCFs at the design, procurement, and construction phases, alongside the differences between NBCFs’ characteristics and related waste minimisation approaches. Subsequently, the extent of adoption of the 3R approaches by the NBCFs, and appropriate waste minimisation strategies and implementation methods specific to the NBCFs, are discussed. This is followed by a description of the existing waste minimisation policies and legislation in Nigeria and willingness of the NBCFs to adopt new construction waste minimisation methods. Then, a circular economy waste minimisation framework is developed. The structure of the framework is described, as well as the relevance and implications of the framework for the NCI. This chapter ends with an overview of key findings. For ease of reference, this chapter is organised as per the research objectives (see Section 1.5). The discussion under each objective provides a summary of the results and interpretations of the findings. A comparison between the findings and the relevant literature is then provided prior to a description of the relevance of the study to policy, industry, practice, and culture.

224

6.1 Objective 1: To Identify the Types, Causes, and Disposal of Material Waste in the Nigerian Construction Industry 6.1.1 Types of Material Waste Concrete, ceramic and stones, off cuts of tiles, and timber products are the commonest types of material waste in the NCI, as shown in Tables 5.5 and 6.1, These products are the most commonly used in most construction projects (Napier, 2012; Gihan, Ahmed, & Adel, 2010; Thongkamsuk, Sudasna, & Tondee, 2017; Bakchan & Faust, 2019; Tam, Shen, & Tam, 2007); therefore, the high amount of waste related to these products is unsurprising.

Table 6.1: Synthesis of types of material waste

Quantitative Results Qualitative Results Concrete, ceramic, and stone Types Interviewees’ responses Mean = 2.85 Off-cut of tiles “We are not at the finishing stage where St. Dev. = 1.70 there will be a lot of waste from tiling, but Rank = 1st even when we did the model room, we generated a lot of waste from offcut[s] of tiles which you can see everywhere on the site” (PM8). Wood “…the other material wastes that I see is being generated on site is the wood used for formwork” (A6). Concrete “Sometimes when you mix concrete and [it] is more than what you need, it becomes a waste, which brings cost to the project” (A5).

These materials are frequently used for building in the NCI because of their ability to inhibit thermal discomfort (Alausa, Adekoya, Aderibigbe, & Nwaokocha, 2013; Akpabio, George, Akpan, & Obot, 2010), since Nigeria is a tropical country. These findings are supported by previous work that reported that waste is generated from materials that often get used (Angulo et al., 2009; John et al., 2004; Angulo et al., 2003). The use of some other materials also generates significant amount of wastes. For instance, materials such as lime, PVC water pipes, and plastic, have been shown to generate more waste (Bekr, 2014; Al-Hajj & Hamani, 2011). The differences between these studies may be due to the type of construction, technical know- how, and availability of materials. The implications of this finding for practice include the need to adopt substitutes that produce less waste and are biodegradable. Concrete materials such as AshCrete (a material that uses fly ash instead of cement), mycelium (a natural material composed of fungi and mushroom), HempCrete (a material made from inner fibres of hemp), strawbales, and rammed earth have been shown to produce less waste (Xing, Brewer, El-

225

Gharabawy, Griffith, & Jones, 2018; Peckenham, 2016; Gregor, 2014). These are green materials that contribute to water and material efficiency, waste minimisation, and indoor air quality (Sheth, 2016). Their adoption would contribute to reducing waste, greenhouse gas emissions, and improve sustainable construction in Nigeria. In addition, the fact that some of the common types of waste are non-renewable may supress the prevalent culture of materialism and consumerism in Nigerian society, which could lead to a significant drop in demand. This finding should influence government policies on the extraction of finite materials in relation to their usage, management, and possible reuse to slow down the rate of extraction. From this study, it is clear that concrete, ceramic and stones, off-cuts of tiles, and wood contribute most waste in the NCI.

6.1.2 Causes of Material Waste The quantitative results (see Table 5.7 & 6.2) show that the most prevalent causes of waste at the design phase of a construction development are design variations, lack of coordination and communication between design team members, and unclear client specifications. Additionally, the qualitative results (see Table 5.33) reveal that design changes, design errors, and building shape are also common causes of waste at the design phase. These findings indicate that the causal agents of waste at the design phase are multifactorial. However, changes in design, which are considered as modifications in the scope of work specified in contract documents (Sidwell 1999 cited by Suleiman & Luvara, 2016), are common. Design changes (minor or major), resulting from a variety of causes, can result in a large volume of waste during construction. As explained by the interviewees, the shape or form of a building may be one of the factors responsible for design variations. Other causes include the dearth of design information, miscommunication, and long project durations (Wahab & Lawal, 2011).

Table 6.2: Synthesis of causes of material waste

Quantitative Results Qualitative Results

Design Phase Causes Interviewees’ responses Design (design “The causes of material wastage come basically Design changes (RII = changes) from design” (A8). st 0.844, Rank = 1 ) “…the major causes of material waste could be Procurement Phase change in design” (E1).

…most often, architectural design tends to over emphasise aesthetics above the economy and that generates its own waste” (E10).”

226

Quantitative Results Qualitative Results

Substandard materials Procurement “There are so many causes: indecision, design (substandard changes…and substandard materials” (F4). (RII = 0.777 materials) st “The manufacturers or producers of the plywood Rank = 1 ) told us that the plywood can be re-used up to 5 Construction Phase times… we used them twice and we could not use them again because they have reached their Quality of supervision limit” (PM3). (RII = 0.859 Construction “…the reason for material wastage is poor st (Poor supervision” (A7). Rank = 1 ) supervision) “Sometimes the supervision from the engineers

or foremen is not adequate. When you don’t supervise these workmen and artisans, you tend to generate a lot of waste” (E4).

These findings align with previous studies (Polat, Damci, Turkoglu, & Gurgun, 2017; Bekr, 2014; Suleiman & Luvara, 2016; Yana, Rusdhi, & Wibowo, 2015) that identified variations in design as the main cause of waste. In contrast, Polat and Ballard (2004) identified lack of information about materials on design drawings, while Garba, Olaleye, and Jibrin (2016) revealed specification of low quality materials as the main cause of design-related waste. These studies affirmed that the design stage is crucial to construction projects’ success. At the design phase, material waste can be significantly minimised (Osmani et al., 2008). The implication of this finding for practice is for the design team to explore dynamic approaches to minimising design-related causes of waste. For example, they may use contractual agreements, design standardisation, education programmes for clients and design team members, prefabrication, and efficient framing techniques as potential approaches to waste reduction in the design phase (Osmani et al., 2008). It is equally crucial that the project design is agreed through effective communication with all stakeholders prior to the commencement of construction. This finding suggests that there are various design-related causes of waste, but frequent design changes are the main design factor responsible for waste generation in the NCI. A change management system may be developed to overcome this challenge.

The findings also reveal the causes of waste at the procurement phase. In the context of this study, procurement phase challenges cut across sourcing, negotiation, and actual purchasing of products. From the quantitative analysis, the most significant causes of waste at this stage are

227

substandard materials, manufacturing defects, and non-compliance with specifications (Table 5.8). In addition, the qualitative results (Table 5.33) reveal surplus material, substandard material, and material packaging as the causes of waste at the procurement phase. Interviewees confirmed the influx of substandard materials into the market, which they agreed contributed to waste resulting from the need to rework. They also revealed that some materials are procured with defects that are often discovered at the point of use. Another waste source was noted to be excessive packaging. Over-ordered materials, as indicated by the interviewees, are common on projects. This implies that there is a marked tendency to order more materials than required on most projects. Such a practice will contribute to the waste of materials and money. In addition, non-compliant materials are disproportionately prevalent in large batches of materials, as revealed during the interviews. These findings provide a different perspective to other studies. For example, in Turkey, it was shown that difficulties in ordering small quantities of material resulted in over-ordering, which contributed to waste (Polat et al. 2017). In Malaysia, purchasing materials of different specifications was identified as the main cause of waste (Ikau, Joseph, & Tawie, 2016). In addition, ordering errors such as under, as well as over, ordering were identified as responsible for waste generation at the procurement phase (Nagapan, Ismail, & Ade, 2011). These findings suggest that the causes of waste at the procurement phase vary considerably. However, substandard materials, manufacturing defects, non-compliance with specifications, over-ordered materials, and material packaging are significant causal factors contributing to material waste in the NCI.

At the construction phase, both quantitative and qualitative results revealed several causes of waste: the quality of supervision, uninterested attitudes of project team members and operatives, lack of waste management plans on site, haphazard cutting of materials, poor storage systems, inaccurate working, rework, or abortive works (see Tables 5.9 & 5.33). This finding indicates that the causes of waste during the construction phase are associated with the management of construction projects. Therefore, it is necessary to ensure proper management of construction processes, operations, and operatives to minimise waste. These causes are related to the activities of operatives and their supervisors. According to the interviewees, operatives need to be closely monitored to ensure minimal waste of materials. This finding aligns with current literature. For example, Wang, Kang, and Tam (2008) identified lack of management skill and poor supervision as the main factors responsible for waste in China. Lu, Yuan, Li, Hao, Mi, and Ding (2011) stated that a lack of management is responsible for high volumes of waste. In addition, a study by Nagapan et al. (2012) in Malaysia revealed that waste

228 is generated due to a lack of site supervision and management. In Nigeria, Oladiran (2008), Ameh and Itodo (2015), and Dania et al. (2007) also revealed that the main cause of waste in the construction phase was a lack of supervision. These studies suggest that the problem is not country specific, but cuts across all the construction industry sectors. The finding highlights the need for improved supervision and management of construction projects as a whole. With adequate supervision, waste could be minimised. Since supervision encompasses planning, work allocation, decision making, project monitoring, enforcement, and compliance to building codes and approval (Hardison, Behm, Hallowell, & Fonooni, 2014), competent individuals are required. Supervision of both skilled and unskilled labourers is key to any construction project’s success. To facilitate high quality work and at the same time reduce waste, supervisors should be encouraged. The finding reveals that poor supervision accounts for most of the waste produced during construction processes and operations.

From these findings, it can be seen that the causes of construction wastes cut across the design, procurement and construction phases of project delivery. Actual waste is generated at the procurement and construction phases, while decisions taken during the design phase also contribute to waste. The causes of waste during the procurement and construction phases are activity-based, while at the design phase they are decision-based, which is consistent with previous studies (Yana et al., 2015; Nagapan et al., 2012; Al-Hajj & Hamani, 2011; Osmani et al., 2008). Both client and design team are directly involved at the design stage and their decisions significantly impact on the success of a project including waste minimisation. Therefore, there is a need for effective communication and agreement between the client and the design team to ensure waste mitigation strategies are put in place before a project commences. Furthermore, this study suggests the need for operatives and construction professionals to be conscious and mindful of waste causes during procurement and construction activities. The majority of interviewees suggested training and educating all stakeholders to identify waste sources and to employ minimisation measures. It is an open question whether the implementation of the strategies suggested by the interviewees will be effective in reducing waste in the NCI. This should be explored in future studies.

6.1.3 Method of Material Waste Disposal The quantitative results (Tables 5.10 & 6.3) indicate that landfilling, reuse as backfill, and recycling are the most common methods of waste disposal. Table 5.34 also shows the common disposal methods to include cart away by a government agency, landfilling, open dumping, re-

229

selling, and burning. An authority from the government agency responsible for waste management in Lagos state confirmed that waste collected from construction sites is landfilled. This suggests that as waste generation grows, landfill sites, especially those in Lagos will inevitably reach capacity (Olorunfemi, 2011). The lack of relevant policies and regulations may be responsible for the large streams of waste as reported by some interviewees. In addition, the availability of landfill sites and the perception that it is a cheaper option were also highlighted as potential causes.

Table 6.3: Synthesis of methods of material waste disposal

Quantitative Results Qualitative Results

Landfilling – 23.5% Disposal Interviewees’ responses methods Reuse as backfill – Government “Those we cannot dispose – when the 22.2% Agency/ (government agency) come on Friday, they take Landfilling/ them to their landfill. How they dispose is not our Recycling – 21.8% throw away concern but we pay the agency every month to cart them away” (QS8).

“…there is a government agency we partner. They normally come with their trucks and cart away the waste” (E10).

We throw them in the dump where local people come regularly to pick them, as many as they need” (MC2). Re-sell “The wooden materials are sold out to people who used them to cook, while aluminium materials are sold out to those who go and recycle them” (A4).

“We sell them as scraps most times while some we reused them, like, for example, reinforcement bars” (QS10). Burn “Well, good enough wood or timber for what they are, they can get easily consumed by fire. We just pack them together and stack them somewhere then we burn them off” (MC7).

“Sometimes they are burned, which is not really allowed. Sometimes we don’t have a choice [other] than to burn them, although it causes air pollution” (F4)

This finding agrees with the studies of Ola-Adisa, Sati, and Ojonugwa (2015) and Dania et al. (2007), who found landfilling to be the main disposal method for construction waste in Nigeria. Different ways of significantly reducing the large streams of waste going to landfills need to

230 be explored. Waste may be exploited to develop new and innovative materials, such as glass foam and high impact polystyrene (Dachowski and Kostrzewa, 2016). The household waste disposal charging scheme in Nigeria could be adopted for construction waste. The cost of disposal may be reviewed to deter construction firms from sending waste to landfill. Likewise, the Pay-As-You-Throw (PAYT) strategy practiced in some developed countries may be adapted to reduce waste to landfill. The perception of landfilling as a cheap option for waste disposal needs to change to encourage other sustainable disposal options, like reuse and recycling. Equally, the high volume of waste generated indicates that there is potential for future growth in the reuse and recycling industry. The implication of this finding for the industry is that there are potential opportunities for partnerships and CE business models (see section 3.3.2). Recovery and recycling firms may exchange their waste products. Likewise, firms willing to diversify may include waste recycling on and/or off site. This study has provided insights into the methods of waste disposal in the NCI and shows that landfilling is the NBCFs’ main disposal method.

6.2 Objective 2: To Investigate the Awareness, Attitudes, and Perceptions of the NBCFs to Material Waste Minimisation 6.2.1 Awareness of the Effects of Material Wastages The quantitative data revealed construction professionals’ high awareness that an organised construction waste sorting method will increase material reuse and that the recycling rate of waste is low in the NCI. However, a low awareness that material waste is avoidable was observed (see Table 6.4). Company characteristics, including ownership status, main construction activity, and size were not associated with professionals’ awareness.

Table 6.4: Synthesis of the effects of material wastage

Quantitative Results Qualitative Results

An organised construction Awareness Interviewees’ responses waste sorting method will High “…it can lead to hazards such as [a] fire increase materials reuse (RII = incident, which we encountered may be few 0.868) times on this project because of the terrain where we are” (PM7). Waste of materials is avoidable (RII = 0.657) “…. It affects the profit of the construction company. It also diminishes the integrity of H1: Awareness and company the construction company in the sight of the size (χ2 (2) = 1.848, p = 0.397) client. In addition, it translates to clients not willing to pay professional fees” (A4).

231

Quantitative Results Qualitative Results

H2: Awareness and company ownership status (χ2 (3) = Low “Waste is an inevitable thing that we can’t 6.282, p = 0.099) do without, especially in construction, if you work in a kind of environment where we are H3: Awareness and company’s now” (E3). main construction activity (χ2 (3) = 5.942, p = 0.114) “Waste cannot be totally eliminated but how do we make sure we bring it to [the] barest minimum is what I understand by waste management” (MC5).

The qualitative data provided further evidence that most construction professionals are aware of the effects of wastage (such as cost overrun, time overrun, injury, hazard, unkempt site, company’s profit and integrity) (see Tables 5.11 & 6.4). The implication of these findings suggests the NBCFs are suitably positioned to minimise waste. Although awareness does not necessarily translate to changes in attitude, it may influence decisions about waste minimisation.

There was a low awareness of the psychological effects of waste among the NBCFs (see Table 5.11). This aligns with previous studies (Dania, 2016; Dania et al. 2007), which reported that many Nigerian construction professionals have low levels of awareness of sustainable construction, including waste management. Lack of awareness and knowledge of waste minimisation measures is a major constraint to effective waste management (Hassan, Ahzahar, Fauzi, & Eman, 2012) and a factor responsible for waste generation (Papargyropoulou et al., 2011; Al-Hajj & Hamani, 2011).

It can be concluded that construction professionals are not translating their knowledge into practice. This may contribute to the high volume of waste and low recycling rate in the NCI. The relevance of this finding to practice is for professionals to translate their high level of awareness to practice through interactive communication, dynamic processes, integration of multidisciplinary approaches and knowledge brokering to design, procurement, and construction methods. These can be achieved through training, being the first step in ensuring environmental practices by construction professionals and companies (Häkkinen & Belloni, 2011). Therefore, training programmes, workshops, and seminars may be provided at regular intervals to keep professionals up to date. In summary, the data shows a high level of waste awareness and its impact. Whether this level of awareness influences the NBCFs’ attitudes to waste minimisation is yet unknown.

232

6.2.2 Attitudes of NBCFs towards Material Waste Minimisation The quantitative data (Table 6.5) revealed that construction professionals generally exhibit positive attitudes to material waste minimisation. They regard construction waste minimisation as being as important as other construction management functions and they interact closely with team members to avoid waste. The analysis also showed no relationship between a firm’s size, ownership status, main construction activity, and personnel’s attitudes to waste minimisation. The qualitative data provided supplementary evidence that professionals (based on their roles) exhibited both positive and negative attitudes, while some are neutral (see Figure 5.16). These findings imply that a majority of construction professionals exhibited positive attitude towards waste minimisation, albeit, some of them did not prioritise it.

Table 6.5: Synthesis of attitudes towards waste minimisation

Quantitative Results Qualitative Results

I see construction waste Attitudes Interviewees’ responses minimisation as important as Positive “…I don’t overlook them. What I do when I other functions of construction see material waste is to decide that they are management (RII = 0.864) disposed of” (A5).

I find it hard to change existing “I take the issue of waste very serious[ly], work practices (RII = 0.560) especially cement slurry. There is a standard policy of the company which is inside OSP. H4: Attitudes and company size For every project we are in, there are ways (χ2 (2) = 2.247, p = 0.325) we manage our waste and that is where the issue of salvaging some items comes in” H5: Attitudes and company (QS8). ownership status (χ2 (3) = Negative “Since I am not the one generating the 6.101, p = 0.107) waste, I don’t have much to do with managing it, except if it becomes a problem H6: Attitudes and company’s on the site” (E1) main construction activity (χ2 (3) = 1.591, p = 0.661) “I am not involved in the waste on site. All I do is that I monitor it because it has something to do with my own cost control” (QS10).

Neutral “I can’t decide on what to do with waste” (A4).

“I don’t know how waste[s] are disposed on this site’ (PM2)

233

As reiterated during the interviews, some construction professionals and operatives exhibited carefree and nonchalant attitudes to waste. Conversely, some professionals are beginning to relate waste minimisation to their job specifications. They are faced with the challenge of changing existing work practices and misconceptions about the duration of learning new techniques. While recognising that there is a problem with the large volume of waste, only a few construction professionals actively sought ways to reduce it. This may explain the apparent mismatch between their attitudes and their actions toward waste.

The findings of this study align with previous work. For example, a study in Malaysia found that developers are aware of the effects of sustainable practices but are reluctant to apply such measures due to fear of cost overruns (Abidin, 2010). In China, a study by Chang et al. (2018) observed that large construction firms exhibit positive attitudes towards sustainability but do not consider it as important. In addition, Osmani et al. (2006) observed that architects exhibit negative attitudes to construction waste by assuming that decisions made during the design phase rarely generate waste. The findings suggest that professionals need to try new methods or techniques for minimising waste. Since attitudes can change over time, it is important that they maintain a positive approach throughout a project’s lifecycle. A positive attitude would ensure sustainable construction (Pitt et al., 2009; Du Plessis, 2007). The current study shows a wide variation in the attitudes of NBCFs to waste minimisation. To change this, all stakeholders, including operatives, need to take responsibility and be proactive with respect to waste minimisation.

6.2.3 Perceptions of NBCFs on Material Waste Minimisation This study also demonstrates differences in the perceptions of construction professionals to waste minimisation (Table 6.6). The environment was perceived by some professionals to be among the stimulating factors for minimising waste and the need for proper planning and management. Conversely, others hold the view that construction waste is inevitable on projects and that recycling waste benefits are not worth the time it takes to sort them. These findings suggest that construction professionals exhibited both positive and negative perceptions to waste minimisation. The quantitative analysis also showed no relationship between perception and a company’s characteristics (size, ownership status, and main construction activity).

234

Table 6.6: Synthesis of perceptions on material waste minimisation

Quantitative Results Qualitative Results

Through waste management, Perceptions Interviewees’ responses construction site employees Positive “It is important that we do not contribute to can contribute significantly to environmental pollution through waste” protecting the environment (E7). (RII = 0.845) From the environment aspect, it is important The benefits of recycling because these are materials that are being construction waste are not depleted and they are not renewable. It is worth the time required to sort unfortunate that at this age and time, you waste materials for recycling still find wooden formwork on my sites (RII = 0.488) where I could have used plastics, steel and items that I can reuse for many years, but H7: Perception and company then, the truth is that, because maybe the size (χ2 (2) = 4.801, p = 0.091) effect of it on the environment, nobody really cares” (A4). H8: Perceptions and company Negative “…it is inevitable! Wastes are predominant ownership status (χ2 (3) = everywhere. In a construction like this, there 2.082, p = 0.556) is no way you can’t do with a volume of waste” (A3). H9: Perceptions and company’s main construction “…definitely, waste will be generated. activity (χ2 (3) = 3.651, p = There is no way we can avoid waste in the 0.302) construction environment” (PM7).

These findings indicate that positive perceptions of waste minimisation can contribute to efforts aimed at diverting waste from landfills and reducing pollution. Conversely, negative perceptions could imply little or no consideration for waste minimisation. These findings are supported by previous studies (Sichali & Banda, 2017; Kulatunga, Amaratunga, Haigh & Rameezdeen, 2006), which suggest that construction professionals exhibit positive perceptions to green building practices including construction waste, but at different levels. In addition, Zuo, Rameezdeen, Hagger, Zhou, and Ding (2017), Teo and Loosemore (2001), and Adams (1997) indicated that perceptions about construction waste vary among professionals. Construction professionals’ perceptions about environmental protection may be linked to their positive attitudes towards waste, which could influence their decision making (Arif et al., 2013). Lack of training, environmental consciousness, and misconceptions about waste minimisation may be responsible for the variations in perceptions of waste minimisation as revealed by the interviewees. Therefore, the relevance of this finding to practice is for professionals to unlearn old assumptions and perceptions about waste and adopt new philosophical ideas (e.g. zero waste and waste as a resource) and technological advances (e.g.

235

waste prediction apps/software) in minimising waste. Consequently, through the recruitment of environmentally conscious personnel, most firms would contribute positively to minimising waste, thereby reducing pollution.

6.2.4 Relationship between Awareness, Attitudes, and Perceptions The test results of the relationship between professionals’ awareness, attitudes, and perception (see Table 5.14) showed that professionals with a better perception of waste minimisation have positive attitudes (r = 0.204, p ≤ 0.001). According to Ajzen (1991), a relationship between perception and attitude determines the behaviour and decisions of a person. Thus, professionals’ perceptions of waste minimisation will influence their attitudes, and vice versa (see Figure 6.1). This relationship will lead to positive behaviour and appropriate decision making about waste minimisation.

Figure 6.1: Relationship between NBCFs’ awareness, attitudes and perceptions

Based on this finding, professionals’ perception of waste (being an inevitable by-product on construction sites) is responsible for their negative attitude towards material waste minimisation and management. Since attitudes are influenced by perceptions, it is reasonable to say that professionals’ perceptions that the value of recycled or re-used construction materials is minimal (see Table 5.13) may be responsible for their lack of motivation to use recycled materials. This finding agrees with the theory of planned behaviour (Ajzen, 1991), which suggests that behaviour can be predicted through attitudes, subjective norms, and perceived behavioural control. It also supports the findings of Fabrigar (2004) that behavioural decisions are frequently based upon attitudes. In addition, it confirms the findings of Yin, Laing, Leon, and Mabon (2018) that awareness may not translate to behaviour. This study, however, contrasts with Herremans and Allwright’s (2000) findings, which indicates that awareness and attitudes lead to environmental management actions and performance. Increased knowledge and advances in technology over time may be responsible for such disagreements.

236

It is clear from the findings that the issue of waste minimisation is influenced by behavioural perspectives and the implication for policy makers is to consider targeting attitudes and perceptions rather than behaviours. With positive attitudes and perceptions, behaviour-related compliance should be able to be transformed to minimise waste. Likewise, encouraging project players to perceive construction projects as their own can contribute to creating a sense of belonging that would change their perceptions. The idea of project ownership may lead to positive attitudes to waste minimisation among professionals. The finding suggests that attitudes and perceptions determine behaviour and impact waste minimisation decision making.

6.3 Objective 3: To Investigate Current Approaches Adopted by the NBCFs to Minimise Material Waste at Design, Procurement, and Construction Phases 6.3.1 Design Approaches Implemented in Practice by the NBCFs The RII analysis ranks the design approaches adopted by the NBCFs. The top five approaches were to adopt uniform design, consider material logistics, collaborate with others in the supply chain, consider maintenance, service and replacement requirements for each component, and consider the environmental impact of material, while the least ranked approach was to specify recycled content in design (see Appendix B). In addition, the results based on the categories of these approaches identify design for materials optimisation (DfMO) as the most adopted. In a descending order of importance, other approaches included: design for waste efficient procurement (DfWEP); design for off-site construction (DfOC); design for deconstruction and flexibility (DfDF); and design for reuse and recycling (DfRR) (see Tables 5.16 & 6.7).

Table 6.7: Synthesis of design approaches to waste minimisation

Quantitative Results Qualitative Results

Relative Importance Index Design Interviewees’ responses • DfMO (RII = 0.625) Specifying local “One of the decisions I took when I was • DfWEP (RII = 0.624) materials doing the design is that all materials to • DfOC (RII = 0.592) be used must be procured locally. Two, I • DfDF (RII = 0.573) have a very good knowledge of local • DfRR (RII = 0.524) materials, I know their limitations, my design was able to overcome such, and by so doing, I have saved the client a lot of money. I also saved a lot of waste” (A1). Simplification “…we make sure that it is a simple of building design, straightforward, no complication forms

237

Quantitative Results Qualitative Results

as an open floor, open plan design” (A5). Modular “…I will describe the design approach as coordination modular coordination” (F5)

Furthermore, the results of the qualitative data identify design approaches in support of the quantitative data. These include simplification of building forms, uniformity in design spaces, collaboration and communication with other design team members, specifying local materials, use of modular construction, specifying prefabrication or off-site manufacturing of building elements, consideration for re-use potential of materials, consideration of maintenance services, and consideration for material logistics.

The approaches categorised as DfMO are to adopt uniform design (e.g. room sizes, floor to ceiling heights, and material sizes), consider maintenance, service and replacement requirements for each component, simplify the building form, layout and elements, use local materials, and specify recycled content in design. According to WRAP (2009a), these approaches offer potential opportunities for materials resource efficiency and a reduction of waste without compromising project design. DfMO is widely practiced by the NBCFs because it forms part of the education and training of design professionals. For example, one of an architect’s duties and responsibilities is to develop architectural design using standard dimensions for building structures. As indicated by most interviewees, these approaches are adopted because they are easily understood by all project players and are not difficult to implement. This implies that through simplification and standardisation of materials and components, waste can be minimised. The findings of Garba et al. (2016) and WRAP (2009a) support this approach. Other design approaches categorised as DfWEP, DfOC, and DfDF are listed in Table 5.15. These approaches are capable of diverting waste from landfill (Ajayi & Oyedele, 2018a). Similarly, WRAP (2009a) observed that their application at the design phase will identify areas of potential waste reduction. Garba et al. (2016), and interviewees, confirmed that design approaches to waste minimisation are driven by the need to reduce cost rather than to reduce waste, despite professionals’ awareness of the effects of waste. This confirms previous findings of this study that awareness does not translate to decisions. Conversely, the approaches categorised as DfRR (being the least adopted) are to reuse building components and materials, reuse existing buildings and landscapes, use recycled building components and materials, and design with a restricted range of materials. This implies that

238 buildings are designed without considering uses of salvaged or recycled materials. This is common among the NBCFs. DfRR is sparsely considered due to its heavy dependence on virgin materials. This, in turn, confirms the low recycling rate experienced in the country noted during the interviews. Lack of motivation among professionals (Löfgren & Enocson, 2014; European Commission, 2014a) and the perception that recycled materials are inferior (Andrews, 2015) may be responsible. Overall, the findings indicate that design approaches are important factors to be considered for reducing waste and resource extraction. In line with these findings, WRAP (2009a) identified DfMO, DfWEP, DfOC, DfDF, and DfRR as the principles of designing out waste. It supports Ajayi and Oyedele’s (2018b) findings that DfWEP can contribute to waste minimisation by harnessing the commitment of suppliers, purchase management, planning the delivery of materials, and specification of materials. In addition, previous studies (Goulding, Pour-Rahimian, & Arif, 2012; 2015; Lawson, Ogden, & Goodier, 2014) have identified DfOC as a potential waste minimisation technique, while DfDF was acknowledged by Akinade et al. (2017) and Pulaski, Hewitt, Horman, and Guy (2003) as an effective strategy in diverting waste from landfills.

These findings have implications for practice. They suggest that all design approaches should be considered during project design. A checklist may be created to assist in examining suitable design measures. In addition, these design measures should be encouraged during concept development because they can minimise environmental impacts (Esposito et al., 2018). These findings can be useful in helping governments to decide on policies that will divert material waste from landfill. For instance, a policy that assesses design proposals for possible waste generation may be formulated and enforced as a prerequisite for building development approval to enhance compliance. In addition, site waste management plans (SWMP) and deconstruction plans may be required as part of design documentation for approval, as suggested by Oyedele et al., (2013). These efforts may support waste minimisation efforts at the design stage and end-of-life management of buildings, while useful materials may be salvaged through deconstruction rather than demolition. The findings suggest that design approaches (DfMO, DfWEP, DfDF, DfOC, and DfRR) adopted by the NBCFs can ensure waste is minimised throughout all phases of construction, if implemented.

6.3.2 Procurement Approaches Implemented in Practice by the NBCFs The 13 procurement approaches adopted by the NBCFs are listed in Table 5.18. The top three approaches are to purchase durable materials, examine the need for the materials, and

239

adopt just-in-time (JIT) materials delivery. The lowest ranked was to ask suppliers to commit to waste reduction goals (Table 6.8). The qualitative results (see Table 5.18) agree with the quantitative findings. Interviewees’ opinions were summarised to include bulk buying, underestimating materials, buying from local and foreign companies, and buying what is needed, and at the right time. These approaches can be classified into ‘Act’ and ‘Buy’ green (see Table 5.19).

Table 6.8: Synthesis of procurement approaches to waste minimisation

Quantitative Results Qualitative Results

Relative Importance Index Procurement Interviewees’ responses • Purchase durable materials Just-in-time “The method or approach is like we bring (RII = 0.831, 1st) (JIT) [in] at a time what is needed because there • Examine the need for the procurement is no place to haul any material” (E6). materials (RII = 0.753, 2nd) • Adopt just-in-time (JIT) delivery of materials (RII = 0.689, 3rd) • Ask suppliers to commit to Examine the “...we buy based on the need” (E7). waste reduction goals (RII = need for the 0.574, 13th) material

Factor Analysis (Reliability = Bulk buying “Our procurement method has been 0.901) efficient because we buy cement in bulk

and we have silos for its storage” (PM9). • Act Green (Eigenvalue =

6.036, Cronbach α = 0.905) • Buy Green (Eigenvalue = 1.368, Cronbach α = 0.689)

To ‘act green’ implies behaving either in action or reasoning in a way that will not affect the environment negatively. These actions are to be environmentally guided to minimise waste, which will benefit not just clients and contractors but the environment. As indicated by the interviewees, a key measure to acting green is positive attitude, which is important in minimising waste. To ‘buy green’ means to procure goods and services that protect the environment while reducing carbon footprint. For instance, eco-friendly materials such as bamboo, and services that use modest amount of water, power, and fuel fit this category. As suggested by the interviewees, buying green is possible when all stakeholders, especially clients, design team members, and suppliers commit to it. The advantages of acting and buying green, including financial, environmental and corporate benefits (Green Council, 2010), outweigh its disadvantages. This suggests that both “acting green” and “buying green” are

240

characteristics of green procurement that relate to behaviour. Several studies support green procurement as a way to minimise construction waste. For instance, Ajayi and Oyedele (2018b) identified four key behavioural procurement measures that reduce waste. Similarly, Diabat and Govindan (2011), Wong, San Chan, and Wadu (2016) and Annunziata et al. (2016) revealed that awareness, a positive attitude, mutual commitment, understanding and cooperation among the construction workforce contribute positively to green procurement. Furthermore, this finding agrees with Strandberg (2012), that firms’ policies and management systems play a crucial role in implementing green procurement. It buttresses earlier studies (Oyedele et al., 2013; Osmani et al., 2008; Al-Hajj & Hamani, 2011), suggesting that the commitment of suppliers to green procurement to take back unused materials is a key driver for minimising construction waste (Ajayi et al., 2018b). The findings of this study encourage business models in the circular economy, such as the sharing platform, product-as-a-service, and take-back system (See sections 3.32 and 3.7.2.4), and contribute to waste minimisation (Ellen MacArthur Foundation, 2015c, 2016; Zuidema, 2015). In addition, it is relevant for the development of schemes such as the Green Label Scheme (a list of eco-materials with detailed information about their contents and specifications as practiced in Malaysia and Hong Kong (Rashid, 2009; Mesthrige Jayantha & Sze Man, 2013)). Thus, the procurement measures (act and buy green) may be effective in minimising material waste in the NCI provided there is a positive attitude and commitment from all stakeholders.

6.3.3 Sustainable Construction Approaches Implemented by the NBCFs This study identified 15 construction approaches to waste minimisation adopted by the NBCFs. The ranking of these approaches is shown in Table 5.20. The top three approaches are stock control measures, effective teamwork among stakeholders, and avoiding unnecessary waste. The last two approaches were to appoint a waste management contractor and use of no- dig or trenchless technologies. In addition, the qualitative data showed that framed structures, identifying construction activities that can reuse waste, improved construction methods (prefabrication and precast), traditional construction methods, and effective teamwork were the sustainable construction approaches implemented by the NBCFs. These approaches can be categorised into three factors, namely Strategies, Techniques, and Operations (see Table 5.21 andTable 6.9). The factor ‘strategies’ is responsible for six approaches, while ‘techniques’ and ‘operations’ are made up of five and four approaches respectively.

241

Table 6.9: Synthesis of construction approaches to waste minimisation

Quantitative Results Qualitative Results

Relative Importance Index Construction Interviewees’ responses • Stock control measures (RII Use of “…we have been quite pragmatic in the = 0.753, 1st) mechanical sense that we deployed machines on the • Effective teamwork among equipment site and that saved a lot of trouble of waste stakeholders (RII = 0.736, and also human errors” (A1). 2nd) Frame We used a frame structure, and you know • Avoid excavating structure when you do a frame structure you will unnecessary soil (RII = generate less waste. Most of the materials 0.718, 3rd) we reused” (E4). • Appoint a waste management contractor (RII “It is a framed structure, where we started = 0.494, 14th) with the raft foundation, we then extend it • Use no-dig or trenchless up to the columns. Next, we start putting technologies (RII = 0.492, the slabs, extend the column from one layer 15th) to another and then we’ll start the block works” (SC8). Factor Analysis (Reliability = 0.911) Traditional “…it is the traditional construction method method – formwork, concrete and steel” (E1). • Strategies (Eigenvalue = 6.765, Cronbach α = 0.844) ‘The construction method is the in-situ • Techniques (Eigenvalue = system because of the laxity on the part of 1.505, Cronbach α = 0.826) the workers, because there are some times • Operations (Eigenvalue = maybe they are tired and they don’t have 1.070, Cronbach α = 0.766) an eagle eye watching them” (QS8).

Further analysis showed that the factor, ‘strategies’ is the most frequently adopted by the NBCFs. The specific approaches under this factor are to educate construction and management teams on waste reduction, conduct comprehensive feasibility studies, set targets for allowable waste, effective teamwork among stakeholders, improved construction methods, and making waste reduction efforts financially beneficial. These approaches are related to plans of action aimed at reducing waste. One of the strategies was to adopt improved construction methods, such as an industrialised building system, precast construction, and prefabrication. These were also the methods preferred by a majority of the interviewees. With these strategies, waste resulting from in-situ and finishes would be reduced (Poon et al., 2004). The approaches under ‘techniques’ (see Table 5.21) relate to efficient ways of minimising waste during construction. These approaches are project and site specific, as suggested by most interviewees, and are important for every project. To execute some of the techniques, it is essential that project stakeholders possess requisite knowledge and skills (Oladapo, 2007b). For instance, one of the

242

techniques is the use of no-dig or trenchless technologies, which require technical know-how prior to application. This technique would not only reduce waste, it could ensure a greener environment. Although trenchless technology is commonly used for electrical, mechanical, and civil engineering works, it is becoming increasingly popular but is yet to be fully adopted, especially in the NCI.

Construction ‘operations’ is another factor for minimising waste. The approaches under this factor (see Table 5.21) relate to active processes or activities carried out by project stakeholders, and they are vital to the successful completion of construction projects. All approaches under ‘operations’ are activities that could directly reduce material waste when carried out effectively, as suggested by the interviewees. For instance, waste generated from over ordering can be avoided through effective stock control measures. As commonly practiced on most Nigerian construction sites, excavated soil is reused as backfill on and off site, and this is a waste management measure. With this approach, large volumes of waste would be diverted from landfills (Begum et al., 2009). Stock control measures such as taking stock of materials is another operation to minimise waste. This activity encompasses taking an inventory of materials, supply chain management, and material logistics. With effective and efficient stock control, excessive stocking of materials, one of the causes of waste (del Rio Merino & Astorqui, 2009) can be minimised. The majority of interviewees observed that some approaches, especially those identified as strategies, are applicable prior to construction, while others (techniques and operations) are important during construction.

These findings are consistent with extant literature. For instance, a study by Oyedele et al. (2013) and Zhang, Wu, and Shen (2012) identified the need for construction professionals to improve their technical knowledge to enhance waste minimisation efforts. Del Rio Merino and Astorqui (2009) revealed the importance of identifying activities that can reuse materials, while Muhwezi, Chamuriho, and Lema et al. (2012) emphasised adequate knowledge of the construction sequence and how it can reduce material wastage if planned adequately. Furthermore, the findings align with several other studies (Ajayi, 2017; Lu & Yuan, 2010; Osmani, 2013; Al-Hajj & Hamani, 2011; Yuan, 2013b; Jingkuang & Yousong, 2011) that highlight construction techniques as possible approaches to minimising waste. The findings provide valuable inferences in construction projects for stakeholders to deem waste minimisation as an integrative factor. It suggests that proactive measures in the form of strategies at the planning stage, techniques at planning and procurement stages, and operations at the construction stage could divert wastes from landfill. The findings imply that adopting

243

modern construction methods (such as modular construction, prefabrication, and precast cladding) and disruptive technologies (e.g. 3D printing, augmented reality, and living walls) may be effective in reducing waste in the NCI. It is also valuable to note the significance of regulations and policies in facilitating effective construction material waste minimisation. The findings suggest that construction strategies, techniques, and operations are capable of minimising waste.

6.3.4 Relationship between Waste Minimisation Approaches and Company Characteristics The results showed that the construction approaches adopted by the NBCFs vary (χ2 (2) = 8.212, p = 0.016), particularly between medium and large scale firms (p = 0.014). The differences can be explained in the context of the equipment, methods, technology, financial capacity, and personnel employed by these organisations. For example, some of the interviewees revealed that large scale firms deploy heavy equipment, such as payloaders or cranes for activities, whereas these are not used by medium-sized firms. This suggests that the methodology and technology adopted by large firms may be entirely different from medium- sized firms. Despite the differences in construction approaches, there was no evidence of differences in waste minimisation between these firms. The results further showed a variation in design approaches based on the organisation’s main construction activity and procurement approaches. There was a variation in design approaches to waste minimisation across firms during new construction projects, renovations, and maintenance/repair activities. This variation implies different waste minimisation approaches. Similarly, technicalities and materials involved in construction may be different, and that could mean different waste minimisation strategies. For instance, the design approach for a new build may incorporate off-site construction, while maintenance/repair may not. The interview responses suggest that attitudinal differences towards waste may be responsible for the differences in an organisation’s main construction activities. However, there was no evidence that maintenance/repair generates less waste than new build and renovation.

These findings agree with Tam, Shen, and Tam (2007), who argue that waste levels produced from different types of construction activities varies. As evident in this study, attitudes towards waste differ between large and medium sized firms which supports the findings of Teo and Loosemore (2001). The findings also align with previous studies (Abidin, 2010; Chang et al., 2018) that revealed large sized firms perform better than small and medium as regards sustainable construction including waste management. The implications of these findings are for industry, practice and policy. Sustainable construction activities and methods such as

244

prefabrication, trenchless technology, green procurement, and eco designs are beneficial for construction firms. These approaches can contribute to effective waste minimisation and are therefore recommended for the NCI. Construction professionals may need to explore several ways of performing their tasks differently especially as it concerns maintenance/repair and renovation. For ease of disassembly, glue or bolts and nuts may be used to fasten materials together. The implications for policy are to incentivise successful waste minimisation approaches. The findings indicate that construction approaches to waste minimisation differ between large and medium scale firms. Design and procurement approaches vary based on a company’s main construction activity. However, these approaches can be applied by all sizes of firms to different types of construction activity.

6.4 Objective 4: To Investigate the Extent of Adoption of the 3R Principle by the NBCFs The top three approaches of the 3R (Reduce, Reuse, and Recycle) principle adopted by the NBCFs (Table 6.10) were reuse of formwork and falsework, on site reuse of materials, and on- site sorting and segregation respectively. The least-used approach was to recycle waste on site (see Table 5.2). This finding corroborated the qualitative findings, showing that reuse of materials, particularly timber products and reinforcement bars, was common among the NBCFs. The majority of interviewees admitted that they did not recycle due to lack of facilities and policies which required them to do so. In addition, it was also found that recycled materials were of minimal use as they were perceived to be inferior. The factor, ‘reduce’ comprises four variables while the other two (reuse and recycle) consists of three variables each.

Table 6.10: Synthesis of the 3R principle to waste minimisation

Quantitative results Qualitative Results

Relative Importance Index 3R Principle Interviewees’ response • Use of reusable formwork Reduce “We resolve issues relating to design and and falsework (RII = 0.788, construction methodology before we start 1st) any activity. That has helped in reducing • Re-use of materials on site wastage on site” (QS2). nd (RII = 0.735, 2 ) “…we have a routine that we follow. There • On-site sorting and are some activity that we cannot do before segregation of material the other which has helped in reducing rd waste (RII = 0.665, 3 ) waste” (PM1) • Send waste materials to Reuse “…broken tiles were taken away and recycling facility (RII = turned into PALADINA while paint buckets 0.474, 9th) were resold. Materials were not reused on

245

Quantitative results Qualitative Results

• Recycle waste on site (RII = that site but they were reused off the site” 0.453, 10th) (A10).

“…the only material which we have been able to reuse has been our formwork but Factor Analysis (Reliability = we have not used it to the manufacturer’s 0.865) specification. That is just because if the • Reduce (Eigenvalue = environment we are in” (PM2). 4.579, Cronbach α = 0.872) “Formwork are subject to reuse so we do • Recycle (Eigenvalue = reuse that a lot. Like I said, even waste 1.751, Cronbach α = 0.832) generated from sandcrete, we use them as • Reuse (Eigenvalue = 1.161, infill or for back filling” (MC5). Cronbach α = 0.816) Recycle “There is no form of recycling. We don’t have any recycling method” (E5).

“Well, as for recycling, we don’t have the ability to recycle. So, there is no way to recycle” (PM1).

“No! We haven’t done any form of recycling and we do not buy recycled materials” (PM6).

The specific approaches under the ‘reduce’ factor are on-site sorting and segregation of materials, use skips for segregation, evaluation if salvage of used-products is possible, and systems that favour segregation of materials. These are practical approaches that ensure waste is minimised at the point of generation or diverted from landfills. They offer opportunities for potential reuse, which will contribute to reducing pressure on extraction of raw materials for new products. Waste may be reduced by implementing a custom-made checklist of minimisation measures as suggested by the interviewees. This finding confirms the need to implement waste reduction strategies at the planning stages of any construction project (Esa et al., 2017).

The approaches categorised under ‘reuse’ (Table 5.27) imply reusing materials for the same or different purposes. Reuse of material is a common practice in the NCI. For instance, the majority of the interviewees re-sell waste materials such as wood, which is used for cooking. In addition, waste such as excavated soil and excess concrete is used to fill hollow spaces in sandcrete blocks and pot holes in roads. There are many other creative options for reuse on and off site which are yet to be maximised. Sorting and segregation of waste during its generation can contribute to effective reuse of materials. This action may be referred to as “sort-as-you- go” and could encourage reuse and recycling, which is possible with the provision of waste

246 skips as suggested by Ajayi et al. (2017) and Li and Duan (2006). Reused materials such as wood and galvanised roofing sheets have also been shown to be common in the NCI (Mudashiru, Oyelakin, Oyeleke, & Bakare, 2016).

The ‘recycle’ approaches are: using recycled materials, sending waste materials to recycling facilities, and recycling waste on-site. Although recycling has been criticised for its negative impacts on the environment (Saraiva et al., 2012; Chong & Hermreck, 2011; Benjamin & Meiners 2010), it has been identified to be a better waste management option than landfill. As stated in section 6.2.1, recycling is rarely adopted in the NCI. This finding indicates that the benefits of recycling are known to construction professionals, but they not practice it due to their negative perceptions of recycled materials and constraints relating to the lack of supporting policies and facilities (such as waste processing and market).

Previous studies have also reported that recycling is the least considered waste management measure in Nigeria (Eze et al. 2017; Odusami, Oladiran, & Ibrahim, 2012). The lack of recycling has been attributed to the slow development of markets for recycled materials (Mansikkasalo, Lundmark, & Söderholm, 2014). This emphasises the need for resilient markets through appropriate development and upgrade of existing second hand building material stores. In contrast, recycled materials are perceived to be of low quality (Mefteh et al., 2013; Yang and Kim, 2005; Etxeberria, Vázquez, Marí, & Barra, 2007). This research however aligns with Yang, Du, and Bao (2011) and Thomas, Setién, Polanco, Alaejos, and De Juan (2013) that the quality of recycled materials remain unaffected or if not of better quality than their initial state. Although recycling consumes energy and pollutes the environment (Saraiva et al., 2012; Chong & Hermreck, 2011; Benjamin & Meiners 2010), this study agrees with WRAP (2009c) that recycling reduces pollution.

The findings from the current work underscore the need for professionals to embrace the concept of recycling and use recycled materials. This change could be achieved through training, education and personal development. Equally, the industry has to do more for example by developing quality standards and protocol for salvaged and recycled materials. The lack of regulatory policies on recycling emphasises the need to promote the 3Rs through extending producers’ responsibilities, landfill bans, and pay as you throw schemes. For instance, policies that make reuse and recycling efforts beneficial through incentives and awards should be encouraged while taxes on recycling equipment may be suspended to allow the establishment of construction recycling plants, which are scarce in Nigeria. These findings indicate that

247

though recycling of waste is low in the NCI, adoption of the 3Rs, similar to the CE principles (see sections 3.1.3 and 3.7.2.2) can be effective in waste minimisation and management.

6.5 Objective 5: To Identify Policies and/or Legislative Measures for Waste Minimisation and Implementation Methods that are Appropriate for the Nigerian Construction Industry 6.5.1 Policies and Legislative Measures to Waste Minimisation Quantitatively, the top three policy/legislative measures that are appropriate for the NCI are ‘site waste management planning’ (SWMP), ‘appointment of a waste manager’, and ‘construction waste disposal charging scheme’ (CWDCS) (see Tables 5.28 & 6.11). These measures were categorised as government and organisational policies, project specific, project players, best practices, and network systems (See Table 5.3). They are closely related to those identified by the quantitative data, classified as ‘recommended’ and ‘required’ policies. The former comprises of four policies while the latter consists of six. The specific policies categorised as ‘recommended’ are construction waste disposal charging schemes (CWDCS), site waste management planning (SWMP), extended producer responsibilities (EPR), and stepwise incentive schemes (SIS). The majority of the interviewees agreed that these policies were suitable for the NCI but their adoption and implementation depended on policy makers and the industry. Many studies support the promulgation of these policies as appropriate measures to encourage waste minimisation. For instance, the CWDCS, which places a value on all materials and charges a fee on disposal, was adopted in Hong Kong (Lu and Tam, 2013; Hao et al., 2008; Tam & Tam, 2006; Glazyrina, Glazyrin, & Vinnichenko, 2006). The policy was successful in reducing waste sent to landfill by 65% and as at 2006, 65% of total waste in Hong Kong were reduced (Hao et al. 2008).

Table 6.11: Synthesis of policies/legislative measures for waste minimisation

Quantitative results Qualitative Results

Relative Importance Index Policy/Legislation Interviewees’ response • Site Waste Management Network system “I think we need to build a network Planning (RII = 0.867, 1st) system amongst construction • Appoint a waste manager companies that helps to reuse waste (RII = 0.828, 2nd) from other construction site” (A6). • Construction Waste Government “I will rather say that there should be Disposal Charging Scheme regulations policy that the government put in place (RII = 0.825, 3rd) for the construction industry in terms of management of the waste. It is not just what the construction industry put in

248

Quantitative results Qualitative Results

• Contractor’s willingness to place by themselves. The government pay (RII = 0.765, 9th) has to be involved” (E3). • Landfill ban (RII = 0.722, Employing a “I think we should deploy someone that 10th) waste manager will be in charge of materials usage and wastage…the bulk of the work are with Factor Analysis (Reliability the site manager” (E4). = 0.865) Organisational “…if you don’t have policy then, you • Recommended policies have nothing you are working with. (Eigenvalue = 3.993, When you have policy properly written, Cronbach α = 0.742) that is the only way you can minimise • waste” (MC7). Required (Eigenvalue = 1.160, Cronbach α = “It is through policies. We should have 0.748) policies to that effect. Yes, policy statement” (MC10).

SWMP would ensure appropriate waste sorting, segregation, auditing, and divert materials from landfills (Ajayi, 2017). This study aligns with Oladiran (2009b) that SWMP has a significant impact on minimising material and equipment waste. It disagrees with the finding of Tam (2008a) that SWMP reduces productivity and imposes financial constraints on the industry (Tam, 2008a). For example, the Step-wise Incentive System (SIS) proposed by Tam and Tam (2008) is a reward or award scheme given to those producing low levels of waste. It seeks to motivate construction workers to participate in waste minimisation efforts. An incentive scheme similar to SIS was recommended and supported by majority of the interviewees. They suggested that such schemes may be appropriate to save cost and reduce material wastage in the NBCFs. Incentive programmes including reward and award have previously been reported to be effective in minimising material wastes (McDonald & Smithers, 1998; Coffey, 1999).

Furthermore, the specific policies categorised as ‘required’ are listed in Table 5.29. These were regarded as being indispensable for effective waste minimisation by the Nigerian building construction professionals. For instance, pay-as-you-throw (PAYT), which involves payment per volume of waste generated, was suggested as a possible deterrent to landfilling and a motivator for firms to implement appropriate waste minimisation strategies. This is consistent with previous studies (Dahlén & Lagerkvist, 2010; Brown & Johnstone, 2014; Van Houtven & Morris, 1999), which showed that the practical application of PAYT in Canada, Sweden, UK, and Switzerland was successful in reducing heavy dependence on landfills. Another significant example of ‘required’ policy is landfill ban, which prohibits the disposal of construction waste.

249

As observed by the majority of interviewees, implementing a landfill ban may be challenging as many perceive waste to be inevitable. However, it could be achieved over time with appropriate dialogue and consultation with stakeholders and enforcement from the government. A policy that requires firms to appoint a waste manager was also identified as part of the required policies for the NCI. During the interviews, the idea of a waste manager was suggested to be incorporated into the current Health Safety and Environment (HSE) policy. Deciding on appropriate policies/legislative measures may be overwhelming as they are all important. This aligns with the findings of Braunschweig (2010) that having too many policies can be counterproductive. The two categories of policies (recommended and required) can therefore be merged in the context of this study to foster a stronger Circular Economy Waste Minimisation (CE-WM) policy. These findings have implications for practice: first, it suggests the need for organisations to formulate pro-environment and pro-employees (e.g. buy-ins and financial incentives) policies that encourage all employees to see waste minimisation and management as their responsibilities. Secondly, specific policies relating to construction waste minimisation should be distinguished from general environmental policies and identified accordingly. In summary, combining the recommended and required policies to create a CE- WM policy may be effective in reducing waste to landfills and encourage firms to adopt waste minimisation strategies.

6.5.2 Waste Minimisation Implementation Strategies The top three implementation methods for waste minimisation strategies identified in the study were policy, education and training, and legislative systems (see Table 6.12).

Table 6.12: Waste minimisation implementation strategies

Quantitative results Qualitative Results Mean Strategies Interviewees’ response • Policy (mean = 2.53) Training and “…the best way to implement it is • Education and Training Education through series of seminars, talk shows (mean = 2.97) etc…that will enable people to see the • Legislative system (mean benefits of waste management and the = 3.28) impacts on their lives” (A1). Laws and “It still boils down to the policy makers legislation and government. They make the rules and laws” (E3).

“…through government laws and policies” (F5). Communication “There is need for effective communication between the design team and construction team. With that,

250

Quantitative results Qualitative Results you will be able to implement whatever method and eventually minimise waste” (MC1).

Similarly, qualitative analysis demonstrated that policy (organisation and government), training and education (toolbox talks, preparation talks, seminars, and workshops), and communication were important strategies for waste minimisation (See Table 5.38). This indicates that if organisational and government policies are implemented, waste may be reduced. As revealed during the interviews, most government policies in Nigeria adopt the “top-down” approach, which is a system of command and control where the government sets out and enforce rules.

This finding aligns with the study of Huang, Wang, Kua, Geng, Bleischwitz, and Ren (2018) who suggested the establishment of a top down regulatory system to standardise construction and demolition waste management practices. It also consistent with previous studies (Huang et al., 2018; Wong, Chan, & Wadu, 2016; Ajayi et al., 2015; Li et al., 2015) that found the implications of policies such as awards and incentive programmes to be effective for waste minimisation. Training and education suggested in this thesis include topics such as encouragement, motivation, toolbox talk, seminars, workshops, and practical applications of waste minimisation processes. These activities should impart the skills and knowledge required to effectively minimise waste to construction professionals. Furthermore, education and training of staff, personnel, workforce, and supervisors have been highlighted as an effective implementation method for waste management practices (Greenwood et al., 2003; Adewuyi and Odesola, 2016; Kulatunga et al., 2006). It is therefore important that training and education of the construction workforce focus on long term goals (such as improving job performance) which provide a sound foundation for all stakeholders to adopt waste minimisation strategies (Li et al., 2015; Wang, Li, & Tam, 2014; Gangolells et al., 2014; Lu and Yuan, 2010; Wong & Yip, 2004). This finding is relevant for both practice and policy. For practice, it suggests the need for training with practical and visual contents to enhance understanding. Similarly, it indicates the importance of including waste minimisation training as part of compulsory continuous professional development (CPD) programmes. To ensure compliance to policies, it is for the industry and government to consider effective enforcement strategies when formulating policies. The finding suggests that policy (organisation & government) and

251

training and education can be effective in implementing waste minimisation measures in the NCI.

6.6 Objective 6: To Investigate the Readiness of the Nigerian Construction Industry to Adopt a Circular-Economy-Based Waste Minimisation Framework 6.6.1 Existing Organisational Policies on Waste Minimisation Based on the quantitative results (see Figure 5.6), more than half of the respondents revealed that their organisations have a waste minimisation policy. Conversely, the qualitative data showed that the majority of organisations do not have such written policies. This implies that waste minimisation efforts have been at the discretion of professionals and operatives. The lack of policy may be responsible for the indifferent and carefree attitudes of operatives, which Fapohunda and Stephenson (2011) identified as one of the causes of wastes. This study found that policies can contribute to making waste minimisation a routine. They can be effective in correcting behaviours (Knapp and Ferrante, 2012). In addition, the interviews revealed that firms lacking organisational policies tend to generate high volumes of waste. These findings agree with those of Wahab and Lawal (2011) and Dania et al. (2007) that firms with no waste management plan or policy generate larger amounts waste than firms that do have such policies in place. The implication of these findings is that policy would not only encourage waste minimisation but may change behaviours to waste. Policies could be thought provoking by encouraging professionals to rethink their actions and align them with the guidelines. Therefore, written organisational policies may contribute to behavioural changes that encourage waste minimisation.

6.6.2 Willingness to Adopt New Waste Minimisation Method Interestingly, almost all organisations surveyed were willing to adopt any new waste minimisation technique or strategy, if it was cost effective and environmentally friendly. Although the industry has a long history of slow adoption to methods (Oladapo, 2007b), there is a strong indication that it is open to innovations that could be effective especially in minimising waste. This finding implies that technology and strategies for minimising waste can be adopted, but they have to be culturally appropriate, accessible and applicable in the Nigerian context. Therefore, there is need for careful consideration and assessment of waste minimisation strategies before implementation.

This finding aligns with other studies (Harry, 2013; Adzroe & Ingirige, 2014; Okejiri, 2011) that any new technology or strategy should be compatible with the cultural, environmental, and socio-economic needs of the industry. This study informs both practice, research and

252 development. For practice, it suggests the need to examine existing technologies to ensure their applicability. Some technologies (e.g. surface piping) have been abandoned in the past as a result of their incompatibility. It is an open question whether technology will be effective or not. However, further studies may address this gap. Research and development of tailor-made waste minimisation strategies for the NCI is long overdue. This suggests the need for collaboration between the industry, academia and government. Such collaboration can be achieved through adequate funding and motivation (incentives and awards or recognitions). Although several investigations have been conducted with positive outcomes and recommendations for the industry and government, there has been little or no implementation of the findings. It is important that researches are conducted with rigour and findings are validated and implemented. The finding suggests that the NBCFs are willing to adopt new waste minimisation methods that are applicable and appropriate for the industry culture.

6.7 The CE-Based Construction Waste Minimisation Framework (CE-CWMF) The proposed CE-CWM framework is derived from insights of the causes of waste, behavioural factors, minimisation measures, and regulatory policies about waste minimisation discussed in section 6.5. It further highlights issues about compliance and enforcement. It provides guidance to the NBCFs on appropriate approaches to material waste minimisation to be implemented in the design, procurement, and construction stages. Table 6.13 summarises the benefits of implementing the CE-CWMF and its relevance to policies and practice.

Table 6.13: Proposed CE-CWMF guideline

Key Issues Recommendations Stages CE Approaches Identification • Identify causes of material Stage 1 - • Enabling conditions of waste and waste at the design, Identification of • Business models behavioural procurement, and waste minimisation (Sharing platform & factors construction phases needs Product as a service) • Promote awareness of the effects of material waste • Encourage positive attitudes to material waste minimisation • Encourage positive perceptions of environmental factors • Emphasise sustainable construction Waste • Identify current waste Stage 2 - Assessment • Design approaches minimisation disposal options of waste (DfWEP, DfDF, • Identify current waste minimisation DfOC, DfMO, & minimisation measures methods DfRR)

253

Key Issues Recommendations Stages CE Approaches • Identify appropriate waste • Construction minimisation methods approaches • Assess NBCFs’ readiness to (Strategies, adopt waste minimisation Techniques, and measures Operations) • Procurement approaches (Act green and Buy green) • Assessment Tools (e.g. LCA, MFA, IoT, RFID) • Business models (Circular supply chain, Reuse & recycling, and building products to last) • Utilisation of renewable energy Policy • Identify existing Stage 3 - Policy • Top-down policy decision organisational policies for identification and approach waste minimisation formulation • Bottom-up policy • Identify existing government approach policies for waste • Recommended minimisation policies (CWDCS, • Identify appropriate policies SWMP, EPR, Step- for minimising waste wise incentive scheme) • Required policies (PAYT, Landfill ban, WTP, Waste Manager) Enforcement • Identify appropriate Stage 4 - • Training and and implementation methods Implementation of education compliance • Assess NBCFs’ willingness appropriate policies to comply with policies • Educate and train construction workforce about policies • Enforce new policies • Incentivise and penalise as appropriate Validation • Trial policies Stage 5 - Evaluation Future study • Appraise their effectiveness of the framework

6.7.1 Introduction to the CE-CWMF guideline The guidelines and processes are divided into five sections to achieve efficient waste minimisation. The first section of the CE-CWM framework, which is the identification of waste minimisation needs, aligns with knowledge and awareness, and describes the causes of waste during design, procurement, and construction phases as well as construction professionals’ 254

awareness, attitudes and perceptions of material waste minimisation. The second section, which is the assessment phase, aligns with persuasion. It describes efforts to minimise waste in terms of design, procurement, construction, and the 3Rs approaches thereby promoting awareness among construction firms and encouraging their adoption. The third section aligns with decision, and describes the use of regulatory policy measures to enforce waste minimisation among construction firms. The fourth section identifies appropriate implementation methods for the industry and the application of the CE-CWM framework in the NCI. It also provides sample contents of the proposed CE-WM policy. The fifth section, which is evaluation, aligns with confirmation and assesses the effectiveness of the proposed CE-CWM framework in practice. Overall, the proposed framework is intended to facilitate effective construction waste minimisation for building construction firms and professionals by diverting waste from landfills and facilitate SD. The diffusion of innovation theory (see Section 3.8.1) underpinning the proposed framework, and the details in Table 6.13 and Figure 6.2 align with the processes explained in the modified innovation-decision process (see Figure 3.9). These set a benchmark for policymakers, future research, and other related frameworks.

255

Stage 1 Stage 2 Stage 3 Stage 4 Identification of WM needs Assessment Policy identification Implementation

• Assessment Tools (e.g. LCA,

MFA, RFID, IoT) • CircularMedium supply vs chain Large

• Utilisation of renewable energy

Attitudes Awareness Perceptions Procurement 3Rs Principle Approaches • Reduce

• Recycle • Act green • Reuse • Buy green Behaviour Training and Education

Causes of material waste Policy/Legislation Waste • Design – Design changes Minimisation • Recommend

• Procurement – Substandard • Require materials & Material surplus • Construction – Poor

supervision CE-Waste Minimisation Design Construction Approaches Policy Approaches • Enabling conditions • DFWEP • Strategies • Business models (Sharing • DFDF • Techniques platform & PaaS) • DFOC • Operations • DFMO

• DFRR 256

Figure 6.2: Proposed Circular Economy Construction Waste Minimisation Framework 6.7.2 Composition of the CE-CWMF guideline 6.7.2.1 Section 1: Identification of Waste Minimisation Needs The first step in the framework is identification of waste minimisation needs. As described in section 6.3.1, the main design waste cause is design changes or variations, which can be traced to the behaviour of design team members and their clients. Their attitudes, perceptions, and awareness including their expertise and other external factors (such as technology, weather and inflation) contribute to design changes while construction is under way. The adoption of the design principles suggested by WRAP (2009a) and referred to as design for the environment should assist design team members in reducing waste. The main cause of material waste at the procurement phase has been identified as substandard materials. This issue could be alleviated by testing all materials before they enter the market, enforcing building codes and standards, and protecting consumers’ right. Similarly, the commitments of manufacturers and suppliers to ‘take back’ schemes (see Section 3.3.2), would mean that surplus or damaged materials could be returned. As for the construction phase, this study found poor supervision resulting from lackadaisical attitudes and incompetent supervisory team members as the main cause of waste. Lack of waste minimisation knowledge, approaches, and techniques may be responsible. However, there is need for training and education with practical demonstration on how to minimise waste. Consequently, the idea of ‘supervise the supervisor’ may be another possible solution to ensuring adequate supervision.

The causes of waste identified in this study may be associated with the construction workforce’s behaviour. Although this study found construction professionals to have positive attitudes towards waste minimisation, the high volumes of waste generated do not align with their attitudes. The findings showed that respondents were willing to change their attitudes if incentives and training were provided, suggesting that these strategies may lead to positive attitudes to waste in the NCI. Stepwise incentive schemes have previously been shown to be successful in increasing awareness about waste, reducing waste generation by 23% in Hong Kong (Tam & Tam, 2008). Other ways of creating awareness about waste minimisation included continuous workshops and seminars for construction professionals; these could encourage positive behaviours. A previous study has also suggested that the payment of training allowances to construction workers, particularly tradespeople would encourage positive attitudes to waste minimisation (Ho, 2016; Agapiou, 1998). Evidence shows that 29.3 million Nigerians use social media in 2018 and it is projected to reach 36.8 million in 2023 (Statista, 2019). Therefore, another option to create positive attitudes is to develop workshop

257

training modules on social media or mobile apps for self-paced learning (Newzoo, 2018). Peoples’ perceptions influence their attitudes. Construction professionals’ perceptions of waste were observed to vary in the study. However quality and cost of construction projects appear to receive more consideration than environmental factors. Nonetheless, this study found that NBCF’s perceptions of the need to reduce construction waste improves their attitudes to waste minimisation.

The CE approaches that are applicable to stage 1 of the framework were identified as ‘enabling conditions’, ‘shift in consumption patterns’, and the CE business model. Enabling conditions in this context are a means to promote awareness and education about waste minimisation. For instance, the government might provide enabling conditions through incentives and the establishment of educational institutions such as technical schools and research institutes. A relevant example is the New South Wales government’s “Waste Less, Recycle More” program, which provides incentives for recycling (NSW EPA, 2016). Similarly, the UK government rewards and recognises people with initiatives to reduce, reuse and recycle waste (DEFRA, 2011). The building construction industry may provide the enabling conditions through organised CPD and recognition of achievements. For example, the Hong Kong Institute of Construction Managers and Hong Kong Institute of Project Management organised a joint CPD seminar on smart waste management to educate their members (HKICM, 2018). Regular team meetings, toolbox talks, and incentives for training attendances may promote awareness, positive attitudes, and perceptions to waste minimisation. Sharing platforms and product as service models are the CE business models that are appropriate for the NCI. A shift in the current linear consumption of materials to a more collaborative consumption pattern may be effective in minimising material waste. For instance, materials that are no longer needed may be donated to a second-hand building material store or given to those in need. In addition, buildings may be constructed for the purpose of communal housing, building equipment may be leased, and office spaces may be shared. The product-as-a-service model may be more appropriate for the NCI of all the CE business models. These products can take the form of building components and fixtures such as windows, doors, electrical fittings, lighting fittings, and carpets which are delivered as services rather than purchased outright. For example, a company producing kitchen pods may render services such as installation and maintenance while retaining ownership of the pods. Although acceptance of this CE approach may be slow, increased awareness, education, training, and policies may facilitate its adoption in the NCI.

258

6.7.2.2 Section 2: Assessment of Waste Minimisation Methods This section provides a guide for assessing and identifying current waste minimisation measures based on the phase of waste generation. This study has shown that the main disposal method for material waste in the NCI is landfill. Based on this finding, four waste minimisation approaches have been identified as potential solutions.

First, the design approaches identified (DfMO, DfWEP, DfOC, DfDF, and DfRR) were viewed by participants as suitable for most construction projects. Although DfMO was ranked first, construction firms need to analyse these approaches on a project-by-project basis to identify appropriate measures such as uniform design (e.g. floor to ceiling height), use of local materials, and simplification of building form, layout and element. It is also important that these methods are also considered for maintenance and renovation projects since these were ranked second and third respectively to new build in terms of project specialisation (see section 5.1.2.2). Second, the procurement methods identified (see section 6.3.2) have been categorised into two – act green and buy green. The category, ‘act green’ as suggests that professionals’ activities or reasoning during this process should be environmentally motivated. For instance, they should consider buying materials that do not contain toxic and hazardous ingredients. Similarly, at the end-of-life of materials, repair, reuse, and recycling options should be considered. These will reduce waste that causes environmental pollution. On the other hand, ‘buying green’ implies that the procurement of green products contributes to minimising waste and reducing greenhouse gas emissions. For instance, professionals may be required to purchase durable materials to avoid the need for frequent replacement or renovation. This action, when encouraged by the industry through continuous training and awareness, should benefit the environment and clients in terms of reducing pollution and lowering renovation or repair costs respectively.

Third, several construction approaches for minimising waste have been identified (see section 6.3.3). They have been categorised as ‘strategies’, ‘techniques’, and ‘operations’ based on their applicability. Construction firms are expected to adopt strategies that would ensure effective minimisation of waste. It is important to set out strategies before construction begins to ensure adequate preparation for waste minimisation. This study has identified such plans to include conducting comprehensive feasibility studies of sites, setting allowable targets for waste, and adopting modern construction methods. The application of these strategies is central to achieving sustainable construction. Closely related to strategies are techniques, which are practical tools for reducing material waste. These vary based on construction activities. Some

259 of these techniques identified in this thesis include no-dig or trenchless technologies, lean construction, BIM, and ICT tools. These are capable of mitigating waste. Operations, the last category of construction approaches, involve physical actions conducted during construction processes to reduce materials going to landfill. These actions include identifying construction activities that can reuse materials, use excavated soil elsewhere on or off site, and perform materials control and inventory. Importantly, some operations are project specific and may not be suitable for all projects. Therefore, ‘operations’ should be considered for projects where ‘strategies’ and ‘techniques’ are not applicable.

Finally, the 3Rs principle (reduce, reuse, and recycle) has been identified as one of the appropriate waste minimisation measures for the NBCFs. The reduce principle is important for construction activities and should be applied at all phases of construction. For example, ‘evaluating if salvage of used-products is possible’ was identified (see section 5.1.3.13) and may be applied at the end of construction to minimise material waste that are landfilled. Interviewees’ responses showed that the reuse principle has been moderately low. The use of reusable formwork and falsework is an example of the reuse principle. In this context, it is important to use durable materials to increase the number of reuses. The higher the number of reuses, the lower the waste generated. Recycling, the last of the 3Rs, relies on resuscitating dead (waste) materials to either their original form, to a new form (upcycling) or as part of another material. Recycling was found to be rare in the NCI, and was identified as one of the many waste management barriers (Kareem, Asa, & Lawal, 2015). The introduction of on-site or off-site recycling of construction waste should be considered by the NBCFs, as it provides opportunities to reduce waste, costs, and raw material consumption.

The CE approaches that are appropriate at the assessment stage of the framework are design, procurement, construction approaches, CE business model, tools, and utilisation of renewable energy. In addition to these design approaches, other circular design strategies are design for attachment and trust, design for product durability, design for standardisation and compatibility, design for ease of maintenance and repair, design for upgradability and adaptability, and design for disassembly and reassembly (Bakker & Hollander, 2013). These approaches may be effective in minimising waste if they are carefully considered before the project starts. The CE construction and procurement approaches that are appropriate for the assessment section of the framework have been discussed in sections 6.3.2 and 6.3.3. Similarly, the CE business models including circular supply chains, recovery and recycling, and using durable building products form part of the construction and procurement methods discussed in

260 chapter three (see sections 3.3.2 & 3.7.2.4). The circular supply chain encourages the return and reuse of products after their useful lives. This contributes to products longevity and extends consumers value of products. Assessment tools including lifecycle analysis, material flow analysis, internet of things, and radio frequency identification may be used to evaluate the efficiency of waste minimisation methods. The use of renewable energy is another CE approach found appropriate for this assessment section. This approach supports the use of alternative energy forms such as wind power, solar, hydroelectric, and geothermal power to reduce greenhouse gas emissions during construction and material production. Through awareness, education, training, and policies (government and organisational), these approaches contribute possible solutions to the industry’s waste generation.

Overall, the findings of this study show that large and medium scale construction firms minimise waste using different CE approaches. Therefore, regardless of a firm’s size, waste can be reduced without the use of sophisticated equipment or technology. There is willingness and readiness to adopt waste minimisation measures across firms, further supporting their employees’ attitudes to waste minimisation.

6.7.2.3 Section 3: Policy Identification and Formulation Effective waste minimisation is feasible (Lu & Tam, 2013; Tam, Shen, Fung, & Wang, 2007) when appropriate strategies are adopted. However, implementing such strategies may be difficult in the absence of regulatory policies suited to the prevailing practices and culture of the industry. It is important that any waste minimisation policy is comprehensive, purposive, flexible, participatory, and well-publicised (Dror, 2017; Birkland, 2015; Brynard, 2009). Factors that determine the success of a policy include stakeholder involvement, trust, approach, attitude, cooperation, commitment, effective planning and resourcing, management style, ownership, and role delineation (Giacchino & Kakabadse, 2003). Thus, compliance and the success of a policy may be determined by its acceptance and implementation approaches. The current study identified several policies adopted in some developed countries. These were grouped into two – ‘recommended’ and ‘required’ policies. Policies such as SWMP, EPR, and CWDCS (see Section 6.5.1) were recommended for the NCI due to their proven ability to minimise waste. These policies are effective management processes and it is important that both governments and organisations consider them in meeting their management objectives (Zayko 2006). Before their adoption, it is also imperative that the suitability of these policies to the work environment are considered.

261

On the other hand, ‘required’ policies are those that are essential for minimising waste, and include landfill bans, financial incentives, PAYT, and appointment of waste managers (see Section 6.5.1). These policies are central to achieving SC and need to be enforced at the industry and organisational levels. Such enforcement should lead to changes in the way waste is generated, thereby increasing efforts to minimise and manage waste. While there are no explicit government and/or organisational regulations for minimising construction waste in the NCI, the framework has identified two sets of legislation – ‘required’ and ‘recommended’ – for this industry. Awareness and education may contribute to their acceptance, and implementation is required to ensure they progress past this point. Though there are multiple complicated and complex challenges in promulgating policies and/or legislation, policymakers should be considerate and objective in order to get such acts passed. Notwithstanding this, there is a need for continuous dialogue and communication with all project stakeholders to increase their awareness of these policies. Such interventions will improve NBCFs understanding of the purpose of such legislation (i.e. to influence decisions) and benefits. However, the existing national environmental (construction sector) regulations that relate to the industry lack details about what, when, why, and who should manage waste (see section 2.7.4.4). Thus, the proposed circular economy waste minimisation (CE-WM) policy synchronises and consolidates all ‘recommended’ and ‘required’ policies, making them beneficial for material waste minimisation.

The CE approaches appropriate for stage 3 of the framework are top-down and bottom-up policy approaches. They are implementation methods that are essential for the “recommended”, and the “required” policies. As the name implies, top-down approaches are operational directives or decisions that stem from the top-level authorities, to be carried out at lower levels. In the case of government, top-down approaches may involve regulatory policies that are binding on all citizens. They include organisational policies or directives requiring full compliance by employees. On the other hand, bottom-up approaches are based on ideas generated by those directly involved in waste generation and management, which are then translated into policies. For instance, an effective waste minimisation approach employed by operatives over time can influence organisational policy, if the goals are well communicated (Gallup, 2018). In the construction industry, both top-down and bottom-up approaches are applicable (Youssef, Mallet, Chehata, Le Bris, & Gressin, 2014; Kumaraswamy et al., 2004) and have the potential to change waste management behaviour in the NCI. Previous studies (Sammalisto & Brorson, 2008; Veronesi & Keasey, 2009; Aulich, 2013) have emphasised the

262 need for effective communication before policy implementation. Therefore, it is important to adequately study the environment and hold multiple stakeholder meetings to decide appropriate approaches for policy implementation in the NCI. Furthermore, a pilot test of the approaches is recommended to identify areas of complexities and to understand peculiarities before the final policies are introduced, as suggested by World Resource Institute (2014).

6.7.2.4 Section 4: Implementation of Appropriate Policies Implementation is critical in translating policy into action. The implementation of the CE-WM policy is context-specific, as it deals with construction waste minimisation. It depends on the industry culture and attitudinal factors of the construction workforce. Table 6.14 presents the major policy directions for the CE-WM policy proposed in this study.

Table 6.14: Proposed major policy directions

S/N Sections Directions/contents 1 Definition of terms 2 Recommended legislation Construction Waste Disposal Charging Scheme Site Waste Management Planning Extended Producer Responsibility Step-wise incentive scheme 3 Required legislation Pay-As-You-Throw Landfill ban Financial incentives for operatives Appointment of a waste manager Waste prediction tools Willingness To Pay 4 Preparation Circular Economy licensing Permits and Approvals to include SWMP 3Rs minimum requirements 5 Recovery Salvaged items Reusable items Sale of reusable items 6 Recycling Source separation Recovery of recyclables Sale of recyclables Recycling facilities 7 Loading and transport Government Private 8 Waste by-products Hazardous waste Special waste Residual screened materials 9 Waste disposal Prohibition of construction materials for disposal in landfills Disposal in existing landfills Exclusions for landfills 10 Roles and responsibilities Construction firms Government

263

A policy that is poorly implemented is of little value. Therefore, it is important that construction firms adopt appropriate implementation methods. Training and education are required to make the construction workforce more familiar with policy guidelines and their applications. It is expected that through these methods, construction firms can create awareness and inform their workforce about CE-WM policies. Such approaches can assist in policy adoption and complement other waste minimisation measures. Moreover, acceptance of a CE-WM policy (i.e. a combination of policies listed in Table 6.14) is crucial in enforcing waste minimisation measures (see section 6.3.3). The data collected for this study indicate that the NBCFs are willing to adopt any policy that is proven to be effective and efficient in minimising material waste. It is therefore important that CE-WM policies, and the entire framework, are evaluated to determine their effectiveness.

6.7.2.5 Section 5: Evaluation of the Framework Evaluation is the last step of the framework. It is the stage where areas for improvement and modification for successful implementation of the framework are identified. This phase of the framework requires a longitudinal follow-up, and has not been conducted because it is beyond the scope of study. Future studies should evaluate this framework, using both formal and informal methods to appraise its overall impact. For instance, formal evaluation may use performance indicators that are directly related to the framework. Informal evaluation includes feedback from the construction workforce directly involved in the application of the framework or through direct observations of its effects. Formal evaluation allows for in-depth assessment of the framework through standardised measures (e.g. simulation) to determine and assess whether the performance targets set by organisations and policymakers have been met.

6.8 Summary of Key Findings and their Implications Table 6.15: Summary of key findings

Key findings Implications and recommendations Objective 1 Concrete, ceramic and stones, off-cuts of There is a need to substitute materials that tiles, and wood contribute most waste in the generate large amounts of waste with others NCI. that generate less waste, such as green materials. In addition, some of the materials that generate most waste are non-renewable. This finding should influence government policies on the extraction of finite materials in relation to their usage, management, and possible reuse to slow down the rate of extraction.

264

Key findings Implications and recommendations The causes of waste at the design, There is a need for effective communication procurement, and construction phases differ. and agreement between the client and design team to design out waste before the project commences. Such action encourages professionals and operatives to be conscious and mindful of waste causes during procurement and construction activities. Design teams need to explore dynamic approaches to minimising design-related causes of waste. Landfilling is the main disposal method This finding implies that landfill is perceived adopted by the NBCFs. as a cheaper option for waste disposal and, due to the lack of laws that discourage this, most material waste ends up in landfill sites. There are potential opportunities for circular economy business models to divert waste from landfills. Firms willing to enlarge their fields of operation may include waste recycling on and/or off site. Objective 2 There is a high level of awareness of the With quality training, many construction effects of wastage. Likewise, there is a low professionals would translate their awareness level of awareness that waste is inevitable. of waste into practice through innovative design, procurement, and construction methods. Training programmes, workshops, seminars, and talk shows may be provided at regular intervals to keep professionals up to date. Attitudes (positive, negative, or neutral) The construction workforce should maintain towards waste minimisation vary among positive attitudes throughout a project’s construction professionals in the NCI. lifecycle. There is a need for professionals to try new cost-effective waste minimisation methods or techniques without fear of failure. Construction professionals hold different The implication of this finding is for perceptions about waste minimisation. construction professionals to transfer their positive perceptions into practice and unlearn old assumptions and misconceptions about waste minimisation and the environment. Through the recruitment of environmentally conscious personnel, most firms would contribute positively to reducing waste, thereby ensuring a pollution-free environment. Positive attitudes and perceptions determine With positive attitudes and perceptions, behaviour, which impacts decision making. behaviour towards waste may be changed. The work recommends that the construction workforce be encouraged to see their project

265

Key findings Implications and recommendations as their own, which could lead to positive attitudes and perceptions. Objective 3 Design approaches (DfWEP, DfDF, DfOC, During the construction process, there are a DfMO, and DfRR), including circular variety of design choices to minimise waste. design, can ensure waste is minimised The decision about which one to adopt rests throughout all phases of construction. with construction firms and professionals. The study therefore recommends the introduction of SWMP as part of the design documentation required for council approval. Procurement measures, act and buy green, The key to acting and buying green is a can be effective in minimising material waste positive attitude with commitment, in the NCI. suggesting that procurement decisions are carefully taken. Policies supporting the establishment of green markets should be formulated. Construction strategies, techniques, and Waste minimisation should be treated as a operations are capable of minimising waste. holistic factor in construction projects, requiring proactive measures rather than reactive. Construction ‘strategies’ may be efficient at the planning stage, ‘techniques’ at the planning and procurement stages, and ‘operations’ at the construction phase. Regulatory policies that encourage adoption of disruptive technology in the industry, strengthening new and existing construction laws, may help. Construction approaches to waste Large scale firms are better positioned to minimisation differ between large and minimise waste, but there is no evidence to medium scale firms. indicate that they generate less waste than medium and small scale firms. Incentives may encourage waste minimisation practices.

Design and procurement approaches also Construction firms need to review their vary based on a company’s main activities that generate waste and adopt construction activity. appropriate design strategies to mitigate waste. Objective 4 Recycling of waste is low in the NCI, and the Encouraging sort-as-you-go would improve adoption of the 3R, which is the same as the sorting and segregation of waste, which is CE principles, can be effective in waste vital to the reuse and recycle principle. This minimisation and management. finding suggests the need to develop and upgrade the existing second-hand market for recycled and salvaged products to encourage their use. Through training and education, professionals’ perceptions of recycled materials can be changed. Objective 5

266

Key findings Implications and recommendations ‘Recommended’ and ‘required’ policies ‘Recommended’ policies, such as SWMP, combined as CE-WM policy can be effective CWDCS, EPR, and the stepwise incentive in reducing waste to landfills and scheme, might enhance proper waste encouraging firms to adopt waste minimisation, while ‘required’ policies, such minimisation strategies. as a landfill ban, PAYT, WTP, and waste prediction tool, could force firms to reduce wastes going to landfills. The categories of policies can be combined as one CE-WM policy to reduce complexities. Policymakers need to study the industry in order to provide appropriate policies while government improves enforcement. Policy (organisation and government), and Continuous training and education would training and education can be effective in the improve the knowledge base of the implementation of waste minimisation construction workforce, while policy would measures. guide implementation of waste minimisation strategies. Training, including toolbox talk, encouragement, and practical application of waste minimisation measures, is recommended, as well as effective enforcement strategies. Objective 6 Organisational policies can contribute to Lack of plans or policies leads to negligence, changing behaviour. which may be responsible for high waste on construction sites. Incorporating and enforcing company policy about waste minimisation into everyday activities may lead to positive behaviours. The NBCFs are willing to adopt a new waste For any new waste minimisation method to minimisation method that is applicable and be successful, it has to be compatible with the appropriate for the industry culture. cultural, environmental, and socio-economic needs of the industry. Collaboration between the industry, academia and government to implement waste minimisation methods is recommended.

This chapter also discussed the CE-CWM framework for diverting material waste from landfill and promoting SC. The framework is comprised of five main sections and addresses the need for waste minimisation, assessment, policy identification and formulation, implementation, and evaluation. Analysis of the framework highlighted the need for CE-WM policy to be comprehensive, flexible, purposive, participatory, and well-known. Similarly, it identified the need to consider industry culture during implementation to ensure smooth application and compliance. The framework is mainly intended as a guideline for enhancing material waste minimisation on construction projects and assisting those responsible for managing organisations to take proactive steps to minimise waste before it is generated. More

267

importantly, the developed framework is flexible and may be applied at different stages of construction. Although waste minimisation measures have been explored in Nigeria, no academic study has identified or developed a minimisation framework. Therefore, the CE- CWM framework developed in this thesis may serve as a reference for minimising construction waste in the NCI. The framework has implications for the environment, economy, and culture. When implemented, it may contribute to reducing waste through circular design, procurement, and construction approaches, encourage utilisation of renewable energy, decrease pollution, increase use of durable products, and minimise extraction of infinite raw materials through reuse and recycling. Similarly, it has the ability to improve economic growth through sustainable consumption, circular supply chains, and product-as-a-service models. It may reduce cost overruns and minimise the influx of substandard materials while ensuring quality at a reasonable cost. In addition, the framework may promote social interaction through sharing platforms such as communal housing, land sharing, and equipment sharing. Overall, with the adoption of the CE-CWM framework in the NCI, the commitment of firms to waste minimisation, health, and safety may be improved. Increased consciousness of the environment may cause attitudinal changes among construction professionals and yield significant benefits for construction-related firms, industry, and the nation as a whole. The developed framework may change the current status quo around SC in the NCI industry and improve the sustainable development goals.

The following chapter summarises the research by considering the aim, questions, and objectives of the study. It provides an overview of findings and discussions, leading to recommendations for organisations, government, and future research.

268

CHAPTER SEVEN CONCLUSION AND RECOMMENDATIONS 7.0 Overview From the findings of this investigation, the CE-CWM framework for diverting materials from landfill was developed. The study explored waste generation and disposal, behaviours toward waste, minimisation approaches, policies and regulations, and readiness to adopt waste minimisation strategies among building construction firms in Lagos, Nigeria, using a concurrent triangulation mixed methods approach. The development of the framework was guided by the diffusion of innovation theory developed by Rogers (2003).

Chapter two examined key issues related to the construction industry as a whole and to the NCI in particular. These highlighted the need for SC through waste minimisation and reduced extraction of raw materials. The study also reviewed the concept of the CE (chapter three), revealing its principles, drivers, benefits, challenges, and its practicality in the construction industry. Data collected on the causes, behaviours, approaches to, and legislative measures for waste minimisation through mixed methods, analyses, and merging of data were presented in chapter four. The quantitative and qualitative results were provided in chapter five. In chapter six, the implications of the results for practice, industry, and policies were discussed, while the waste minimisation approaches and policies identified were combined to develop the CE- CWM framework. The key findings for each research objective (section 1.4, repeated in Table 7.1 for convenience) are summarised in this concluding chapter. In addition, the chapter details the implications for practice and theory, and offers recommendations and directions for further research.

Table 7.1: Research objectives

S/N Research objectives RO1 To identify types, causes, and disposal of material waste in the Nigerian building construction industry. RO2 To investigate the awareness, attitudes, and perceptions of the NBCFs to material waste minimisation. RO3 To investigate current approaches adopted by the NBCFs to the minimisation of material waste at design, procurement, and construction phases. RO4 To investigate the extent of adoption of the 3R principle by the NBCFs. RO5 To identify policies and/or legislative measures for waste minimisation and implementation methods that are appropriate for the Nigerian construction industry. RO6 To investigate readiness of the NCI to adopt the circular-economy-based waste minimisation framework.

269

7.1 Key Findings of the Study Objective 1: To identify types, causes, and disposal of material waste in the Nigerian building construction industry

The findings indicate that the types of material waste generated in the Nigerian building construction industry include concrete, ceramics and stone, and timber. These products are commonly used and are considered by respondents to be indispensable on construction projects. Respondents identified the main cause of design-related waste to be design changes or variations, while the least frequent cause was errors in contract documents. For the procurement phase, substandard materials and inability to order small quantities were identified as the main and least causes of waste respectively. At the construction phase, the quality of supervision dominates the list of causes, while accidents was the least frequently mentioned cause. An important finding was that material waste was frequently sent to landfill. The availability of landfill sites, absence of clearly defined waste minimisation policies, and non- enforcement of environmental laws were seen to contribute to the adoption of this approach. This finding confirms that the NCI lacks appropriate waste minimisation approaches and alternative disposal methods.

Objective 2: To investigate the awareness, attitudes, and perceptions of the NBCFs to material waste minimisation

The purpose of this objective was to determine the behaviour of professionals and gain a deep understanding of their intentions toward waste minimisation. Behaviour can be considered an underlying factor in achieving effective material waste minimisation. The findings reveal a high awareness level of the low rate of recycling in the NCI and that waste is detrimental to the environment and human health. Interviewees appreciated that sorting waste at source will increase material reuse. However, their awareness did not translate into action, as evidenced by the high volumes of waste that are generated and their low awareness that material waste is avoidable. Attitudes towards waste minimisation were found to be positive, which is important for preventing and deciding on appropriate waste minimisation strategies. Yet, respondents exhibited negative attitudes to changing existing work practices due to their fear of failing to comply with cultural norms. This study’s findings revealed that construction professionals hold different perceptions about material waste minimisation. Professionals with positive perceptions of waste minimisation were found to have positive attitudes. However, their perceptions did not inform their awareness of the effects of waste, which indicates that a high

270

level of awareness may improve people’s knowledge but does not necessarily change perceptions. It was found that attitudes did influence perceptions, indicating that positive attitudes contributed to changed perceptions. This is of utmost importance for the construction industry, because a perception influenced by a change in attitude could contribute to positive behaviour and decisions about waste minimisation.

Objective 3: To investigate current approaches adopted by the NBCFs to minimise material waste at design, procurement, and construction phases

To determine appropriate and effective waste minimisation approaches, the current design, procurement and construction approaches to material waste minimisation were investigated. The design approaches adopted by the NBCFs in the order of preference are: DfWEP; DfDF; DfOC; DfMO; and DfRR. It was found that the current design approach adopted by the NBCFs is DfWEP, which includes consideration of material logistics such as JIT, collaboration with others in the supply chain, consideration of the environmental impact of materials, reducing packaging requirements, and using contractual documents to set waste performance requirements. At the procurement phase, the results of the RII analysis revealed that ‘purchase of durable materials’ (RII = 0.831) was the most popular procurement approach, while ‘ask suppliers to commit to waste reduction goals’ (RII = 0.574) was the least. Two factors – ‘act green’ and ‘buy green’ – were confirmed through exploratory factor analysis. The ‘act green’ factor comprised nine procurement variables and was suggested as the first step to be considered in achieving effective procurement that minimises waste. The ‘buy green’ factor, which comprised four procurement approaches (purchase of multi-functional materials, purchase from local suppliers, examine the need for the material, and purchase of durable materials) was recommended to succeed ‘act green’.

At the construction phase, the waste minimisation approach most frequently identified by the NBCFs was ‘stock control measures’ (RII = 0.753), while the least was ‘use no-dig or trenchless technologies’ (RII = 0.492). Of the 15 construction approaches identified, three factors were confirmed via factor analysis. These factors, in the order of importance and applicability, are: ‘strategies’, ‘techniques’, and ‘operations’. The ‘strategies’ factor was composed of six approaches that deal with actions required at the construction phase to prepare for waste minimisation. This was closely followed by the ‘techniques’ factor, which comprises five approaches (lean construction, use no-dig or trenchless technologies, and adopt BIM and ICT tools). These are technical approaches to waste reduction that are required during

271 construction. The ‘operations’ factor was last, and involved the execution of four approaches (stock control measures, use excavated soil elsewhere on the same site, avoid excavating unnecessary soil, and identify construction activities that can reuse materials). In addition, this study investigated the relationship between waste minimisation approaches and company characteristics. The results indicated that medium and large firms differ in their waste minimisation approaches (χ2 (2) = 8.212, p = 0.016). The differences can be explained in the context of the equipment, methods, technology, financial capacity, and personnel employed by these organisations. The design approaches also varied, based on the main construction activities of companies (χ2 (3) = 16.664, p = 0.001). Similarly, procurement approaches varied (χ2 (3) = 13.796, p = 0.003) between new build and maintenance/repair, as well as between renovation and maintenance/repair, as confirmed by the Kruskal Wallis test.

Objective 4: To investigate the extent of adoption of the 3R principle by the NBCFs

The 3R principle, as an essential component of the CE, ensures circularity of a material at the end of its useful life. This objective focused on the extent of its adoption by the NBCFs to determine the applicability of the CE concept in the NCI. The results of RII analysis identified the top three factors as: ‘use reusable formwork and scaffolding’ (RII = 0.788), ‘reuse of materials on-site’ (RII = 0.735), and ‘on-site sorting and segregation of material waste’ (RII = 0.665) respectively, while ‘recycle waste on site’ (RII = 0.453) was the lowest ranked. The results of the factor analysis confirmed the 3R (reduction, reuse, and recycling) principle. The reduce principle was responsible for four factors, with ‘use systems that favour segregation of materials into their elements at the end of their useful lives’ being the most important. Likewise, the reuse principle was composed of three approaches, and ‘re-use of materials on site’ attained the top position. The recycle principle comprised three variables: ‘send waste materials to recycling facilities’, ‘recycle waste on-site’, and ‘use recycled materials’. The data collected suggested that some waste (such as offcut tiles, timber, and reinforcement bars) were being reused, indicating that the reuse principle was practised to some degree, while the reduce principle was practised a little, and recycling not at all.

Objective 5: To identify policies and/or legislative measures for waste minimisation and implementation methods that are appropriate for the NCI

This objective was to identify policies and implementation methods that are suitable for waste minimisation in the NCI. Results revealed SWMP (RII = 0.867), appointment of a waste manager (RII = 0.828), and CWDCS (RII = 0.825), respectively, as the top three regulatory

272 policies, while landfill bans (RII = 0.722) were the lowest ranked. More importantly, two factors – ‘recommended’ and ‘required’ policies – were confirmed by the factor analysis results. The factor ‘recommended’ policy comprised four variables, which are CWDCS, SWMP, EPR, and Step-wise Incentive Schemes. The other factor, ‘required’ policy, was responsible for six variables that describe the necessity for waste minimisation. They include: PAYT, landfill ban, financial incentives for operatives to sort and segregate waste, appointment of waste managers, use of waste prediction tools, and contractor’s willingness to pay for waste disposal. It was apparent that these policies were lacking in the NCI and may be responsible for the lack of waste minimisation effort. However, if either of the ‘recommended’ or ‘required’ policies are implemented and enforced, they could contribute to diverting material waste from landfills.

Appropriate implementation methods for waste minimisation approaches were also investigated. Quantitatively, the findings revealed that, although the implementation methods differed, policy and goal was ranked first while international cooperation was ranked last. The interviewees also provided insights into different implementation methods. The majority identified training and education as the most important implementation method. The focus of such education and training included construction processes, material management, technology, and project management. Furthermore, the research indicated that policy, education and training, and legislative measures were appropriate implementation approaches for innovations, ideas, methods, or frameworks in the NCI.

Objective 6: To investigate readiness of the Nigerian construction industry to adopt the circular-economy-based waste minimisation framework

This objective addressed two important factors as building blocks for the framework. They are: availability of existing organisational policies on waste minimisation, and willingness of firms to adopt new waste minimisation methods. It was apparent that many construction firms do not have written organisational policies on waste minimisation. In addition, the results of the frequency distribution showed that 89.3% of respondents agreed and strongly agreed that their organisations would be willing to adopt new construction waste minimisation methods. This indicates that the NBCFs are favourably disposed to the proposed CE waste minimisation framework, which suggests that an effective and efficient waste minimisation method could be widely adopted by the NBCFs.

273

Research Aim and Question

It is apparent from the key findings summarised above that the research objectives were achieved. The remainder of this section collates these findings to address the research aim and answer to the research question ‘How can construction material waste in the NCI be minimised using the circular economy concept?

The research question emanated from the lack of literature about material waste minimisation measures in the NCI. To address the question, a mixed method approach combining quantitative and qualitative methodologies through a concurrent triangulation design was adopted. This approach was used to collect primary data from building construction firms to provide logical and practicable answers to the research question. The findings revealed important issues associated with the adoption of the CE concept for waste minimisation. These issues were: identification of waste and behavioural factors, waste minimisation, policy decisions, enforcement and compliance, and validation. Corresponding CE approaches to the issues were identified and adopted to develop the CE-CWM framework.

The findings revealed that the manner in which construction workers deal with materials significantly affects the waste that is generated. Their perceptions and attitudes were found to be related, which suggests that they are key determinants in their behaviours. The CE approaches, enabling conditions, shifts in consumption patterns, and business models were identified as those which encourage positive behaviours toward waste minimisation. For instance, enabling conditions suggest that adequate training and education should be provided to construction workers to develop the skills required for waste minimisation. Likewise, a shift in consumption patterns is likely to encourage reuse and sharing of used materials, which could divert waste from landfill. The business model PaaS inspires organisations to offer building components as services while maximising their value and keeping them functional throughout their lifecycles.

With respect to waste minimisation issues, the study found that sending waste to landfill sites was the main disposal method. This confirmed the need for efficient waste minimisation measures. Currently, the waste minimisation approaches adopted include DfWEP, purchase of durable materials, and stock control measures at the design, procurement, and construction phases, respectively. Design, procurement, construction, 3Rs, assessment tools, business models, and utilisation of renewable energy were the appropriate CE approaches identified for waste minimisation. All five design approaches (DfWEP, DfDF, DfOC, DfMO, & DfRR) play

274

significant roles in minimising waste. Similarly, procurement and construction approaches may be used to divert waste from landfill while reducing environmental pollution. The 3R principles emerged as an effective approach to minimising raw material extraction and waste generation, while assessment tools (such as LCA and MFA) may be used to evaluate different approaches. As revealed in this study, the CE business models (circular supply chain and building product to last) encourage take-back systems and maximise the value of products, while the use of renewable energy contributes to energy efficiency.

Policy decisions are another key issue in developing a CE-CWM framework. A general lack of written policies on waste minimisation by organisations was revealed in this study. The CE approaches to policy direction include recommended policies, required policies, and top-down and bottom-up policies. Both recommended and required policies can be combined into CE- WM policies to ensure comprehensive coverage and efficiency while reducing complexity. Top-down approaches as well as bottom-up approaches were found suitable for the industry. To enhance compliance, it is recommended that suitability checks, trial versions, and dialogue with stakeholders occurs before any policy decision is taken.

Effective implementation is key to the success of policies and strategies. To implement CE- WM policies, this study proposes a ten-section set of directions (see section 6.7.2.4). The fundamental capabilities of the CE-WM policy to influence waste minimisation approaches were confirmed in the study. Training and education to improve knowledge and skills, create awareness, and enhance compliance with policies and waste minimisation measures were identified as the appropriate CE approach for effective policy implementation. For continuous improvement related to approaches, policies, and frameworks, either formal or informal evaluations were recommended for future studies.

The CE-CWM framework has addressed the research aim of developing a circular-economy- based construction material waste minimisation framework. The research gap – the lack of holistic construction material waste minimisation measures – was filled through the combination of appropriate waste minimisation measures (design, procurement, and construction), 3R principles, and legislative measures in a framework. In addition, the research question ‘How can construction material waste in the NCI be minimised using the circular economy concept?’ has been answered through approaches including design, procurement, construction, 3Rs, legislative measures, enabling conditions, business models, and assessment tools.

275

7.2 Contributions to Knowledge The results of this study have practical implications for the industry and theoretical contributions to the body of knowledge in construction waste management research. These are highlighted in the following sub-sections.

7.2.1 Implications for Practice Findings of this study presented in chapter six have both environmental and economic implications for practice. These include:

• Waste minimisation approaches: This study has provided insights into appropriate waste minimisation approaches at the design, procurement, and construction phases in the NCI. The study demonstrates that there are variety of eco-design choices for minimising construction waste but DfMO is most commonly adopted by the NBCFs while DfRR is the least. As a result, construction professionals, especially the design team, need to simplify building forms and ensure that spaces and materials conform to conventional standards. In addition, all eco-design approaches (DfWEP, DfDF, DfOC, DfMO, and DfRR) are appropriate for minimising waste. Design professionals therefore need to consider these approaches during the design phase and enhance their understanding of construction processes and methods. The NBCFs rated the purchase of durable materials and just-in-time delivery as the most important procurement approaches to minimising construction waste, while asking suppliers to commit to waste reduction goals was the least. The study shows that the commitment of all stakeholders, including material suppliers, is crucial in minimising construction waste. At the procurement phase, waste is produced generally from sub-standard materials, defective materials, ordering errors, non-compliance with specification and supplier’s errors (see Section 5.1.3.2). Project stakeholders need to take action (i.e. act and buy green) to reduce waste. This would ensure that they contribute to sustainable procurement and the green supply of products. At the construction phase, this study identifies various approaches to minimising waste. They are mainly: stock control measures, effective teamwork, appointment of a waste manager, use of mechanical equipment and frame structure. Although these approaches are important, construction professionals must be proactive in adopting strategies, techniques and operational measures capable of minimising waste. This could facilitate the use of modern construction methods and disruptive technologies in the NCI.

276

• Design: As demonstrated in the study, design is extremely essential to reduce construction material waste. The main design causes of waste in the NCI are design changes, poor coordination and communication between design team members and unclear specification. This suggests the need for design professionals to consider the implications of waste at the planning phase of construction and using ICT tools such as BIM. These approaches contribute to improving collaboration and communication among design team members and thereby mitigate design variations, which have been reported as the main design waste cause. In addition, this study demonstrates that the introduction of SWMP as part of the documentation required for development applications would ensure waste is minimised. While design professionals are required to understand construction operation, specific and continuous training and education on design approaches and their effects on material waste minimisation are expected to improve their knowledge base. This study has identified five main categories (see Section 5.1.3.9) of design approaches (DfWEP, DfDF, DfOC, DfMO, and DfRR), which could be explored to minimise waste at any stage of construction. • Procurement: Consequently, there is need for manufacturers and suppliers to ensure that materials satisfy building codes and standards while adhering to the requirements of the Standards Organisation of Nigeria. Likewise, if manufacturers and suppliers commit to the take-back scheme, construction waste could be minimised. Another implication is that effective collaboration between suppliers and buyers/users to facilitate just-in-time delivery of materials may reduce waste by supplying the items needed as and when required in the right quantity. Such approach should reduce over- stocking and consequently construction waste. • Construction: The research reveals that poor supervision is one of the main causes of waste during construction. In the NCI, poor supervision results from lackadaisical attitudes of the construction work force and contributes to high volumes of waste. Therefore, it is important to supervise the supervisors themselves. This would ensure adequate monitoring of construction activities and thus reduce waste. There is also a need for consultations with project stakeholders to ensure that supervisors and labourers translate their knowledge of waste minimisation strategies to practice. While all construction team members are responsible for minimising waste, this study highlights the need for contract documents to specify all stakeholders’ roles and responsibilities to avoid duplication of duties. Furthermore, it emphasises the use of waste prediction

277

tools that are specific to the types of waste generated in the NCI. The study shows that the prominent traditional method of construction in the NCI generates waste. On this basis, a complete shift from current traditional methods to modern construction methods (such as modularisation, prefabrication, and off-site fabrication of construction components) is needed to ensure effective material waste minimisation. In addition, there is a need for disruptive technology (such as 3D printing of buildings) to reduce waste generated from construction activities. The NBCFs are increasingly aware of the effects of material waste. This suggest the need to stress the importance of waste reduction and how it can be accomplished. • 3Rs: This study shows that the most common 3R approaches adopted by the NBCFs are use of reusable formwork and scaffolding, re-use of materials on-site and on-site sorting and segregation of materials. The reduction, reuse and recycling approaches are appropriate for minimising the types of waste generated in the NCI. The implication is for design professionals to consider incorporating these principles at the planning phase. In addition, recycling and use of recycled materials are important and should be considered by project stakeholders. While it is clear that markets for reclaimed and recycled products in Nigeria are inactive, this study suggests the need for market expansion to encourage reuse of materials. This could create jobs through sorting and segregation of material waste. • Policies: The study identifies appropriate policies that may facilitate construction waste minimisation in the NCI. These policies include: SWMP, appointment of a waste manager, network system, government regulations, CWDCS and incentives. Though these policies are important, some of them are required in the NCI and will actively enforce NBCFs’ decision on waste minimisation decision, whereas others are recommended and may reduce waste passively. Similarly, the introduction of incentives, awards, and recognition of individuals and firms with high sustainability records may encourage others. The findings suggest that the appointment of a waste manager on each construction project could ensure effective and efficient minimisation and management of waste. This study also supports the establishment of specific policies for construction waste minimisation rather than adopting general environmental regulations or policies. Specifically, such policies should offer guides (design, procurement and construction approaches) to waste minimisation and

278

management, particularly with the willingness of NBCFs to adopt waste minimisation methods that are proven to be effective.

Beyond the general management of waste, the outcome of this study has demonstrated that it is possible to develop a CE-CWM framework that can be employed in diverting waste from landfill. It identified key issues in waste minimisation and provided recommendations for each and highlighted appropriate CE approaches. This suggests that the CE-CWM framework can serve as a baseline for waste minimisation practices in the NCI. While the framework is unique and specific to the Nigerian building construction industry, there is need for collaboration between the industry, academia and government for effective implementation.

7.2.2 Theoretical Implications Based on current knowledge of waste management, this research provides insights into the adoption of the CE in Nigeria’s construction industry. Empirically, the study supports the claim regarding the CE as a potential waste minimisation concept through the development of a CE- CWM framework for the NCI.

• Body of knowledge: Although there is considerable research on construction waste management, this study provides important insights, especially in regard to material waste minimisation. In particular, this study used the Diffusion of Innovation theory as a basis for the development of the CE-CWM framework. As discussed in section 6.7, key issues such as identification of waste minimisation needs, assessment methods, policy decisions and implementation of appropriate policies explained the application of the CE as a waste minimisation concept. Furthermore, while the literature provides separate behavioural and technological solutions to waste minimisation, this study incorporates both in one framework. The literature review in chapter three indicated that the CE is yet to be adopted in the construction industry, though it has been applied in the manufacturing, steel and agricultural industries. Therefore, this study contributes to the literature by developing a framework that can be tested and adopted in the construction industry. Likewise, it supplements the CE concepts by identifying and comparing five additional concepts to the 10 outlined in Geisendorf and Pietrulla’s (2018) study. • Behaviour: The study identified positive attitudes and perceptions to waste minimisation as a major factor contributing to SC in the NCI. Therefore, it contributes to the theory of planned behaviour that suggests that the behavioural intentions of an

279

individual are formed by attitudes, subjective norms, and perceived behavioural control (Ajzen, 1985). This is particularly because results of the Spearman rho correlation indicate that perceptions influence the attitudes, which determines behaviour. The implication is that construction professionals must perceive waste minimisation as a significant aspect of the construction process and exhibit positive attitudes towards it. • Sustainable Development Goals: The findings of this study align with and promote multiple sustainable development goals, as shown in Table 7.2:

Table 7.2: Sustainable development goals achieved

SD Goals Tick Goal 1 - No poverty - Goal 2 - Zero hunger - Goal 3 – Good health and wellbeing  Goal 4 – Quality education - Goal 5 – Gender equality - Goal 6 – Clean water and sanitation  Goal 7 – Affordable clean energy  Goal 8 – Decent work and economic growth  Goal 9 – Industry, innovation and infrastructure  Goal 10 – Reduced inequalities - Goal 11 – Sustainable cities and communities  Goal 12 – Responsible production and consumption  Goal 13 – Climate action  Goal 14 – Life below water  Goal 15 – Life on land  Goal 16 – Peace, justice and strong institutions - Goal 17 – Partnerships for the goals -

• Waste Management Approaches: Prior research has identified various design, procurement, and construction approaches to waste minimisation. The findings of this study confirm by exploratory factor analysis and thematic analysis the key design categories as DfWEP, DfMO, DfRR, DfDF and DfOC. The research further suggest that green procurement is very crucial for minimising construction material waste. The results of relative importance index analysis, exploratory factor analysis and thematic analysis show that behavioural response in terms of action (i.e. act and buy green) are capable of minimising waste. In addition, findings of this study complement and supplement existing construction approaches to waste minimisation. It indicates that construction waste can be efficiently minimised by implementing appropriate strategies, techniques and operational measures.

280

• Methodology: A considerable number of construction management studies have adopted single, mixed, and multiple methods of enquiry. This study employed a mixed methods approach (surveys, interviews and observation) using a concurrent triangulation design to understand and proffer solutions to issues relating to material waste minimisation. This provides new insights into methodological approaches to studies on construction waste, especially in Nigeria, where use of such an approach has not been recorded. It ensures that the findings are representative of the status quo in the NCI.

7.3 Recommendations A number of recommendations are proposed below to guide future policy formulation, and to change industry practice for the benefit of the environment.

7.3.1 Recommendations for Policy In most African countries, including Nigeria, the top-down approach to policy implementation is common. Enforcement and compliance with policies has been reported as low (Dania, 2016). To ensure successful policy outcomes, ground-level actors should be duly involved (Cahn, 2012), and bottom-up approaches may assist in this regard. Since existing regulations do not specifically address waste minimisation, it is recommended that both government and organisations develop policies that target waste issues in construction. Such policies should provide detailed guidelines on waste minimisation and encourage wider adoption among the construction workforce. In addition, it is recommended that government and organisations consider policy implementation and enforce compliance through incentives, awards, recognition and penalties (where appropriate). Policies that regulate both scavenging and segregation activities are recommended, since scavenging activities enhance waste sorting, and segregation activities could lead to a CE. Given the increasing rate of biodiversity loss, there is an urgent need for government regulatory policies to extend to areas, including raw materials extraction and manufacturing, to mitigate the ever increasing exploitation of finite materials and resource consumption common to the industry. A regulatory policy or law compelling all development applications to include SWMP might prompt organisations to consider waste minimisation while planning construction projects. Enforcement of policies and regulations by government agencies in Nigeria is low (Dania, 2016; Ijaiya & Joseph, 2014; Ladan, 2012, 2016); however, this study recommends the development of a regulatory compliance and enforcement framework consistent with international best practices, which could assist in improving waste minimisation.

281

7.3.2 Recommendations for Training and Education Training and education are considered important factors required for skills development. The findings of this study recommend training and education of the construction workforce to increase efficiencies in waste minimisation and the capacity to adopt new minimisation technologies and strategies. Training and education may be formal or informal and could include preparation talks, toolbox talks, orientations, seminars, workshops, and motivational activities. Other forms of training are recommended and encouraged, including in the use of technologies like augmented reality, artificial intelligence, prefabrication, robotics, and virtual reality. The findings of this study recommend that tool box talks and preparation talks, being a form of informal education, should be encouraged before the start of every construction activity to promote a waste management culture. Continuous professional development (CPD) is essential. Construction professionals should invest in personal development by regularly updating their skills and knowledge of SC practices by attending CPD activities to keep up to date with their counterparts in developed countries. CPD courses should be flexible – online, in-house, workshop, or via correspondence – to encourage the participation of professionals. Likewise, these should be practically oriented, and certified by appropriate professional bodies.

7.3.3 Recommendations for Change in Organisational Culture and Attitude To achieve effective waste minimisation, a change in organisational culture and attitudes is recommended. As revealed in this study, a fundamental change from common traditional methods of construction to modern methods that allow for off-site and prefabricated processes would not only reduce construction time but also minimise waste, reduce accidents, and ensure energy efficiency. The findings of this study may help organisations make informed and objective decisions about recruiting employees who demonstrate appropriate skills and competencies, such as environmental consciousness. Therefore, it is recommended that construction professionals, through innovative and creative ideas, become advocates for appropriate waste minimisation and disposal. With such attitudes, construction professionals would be proactive in minimising waste. Through active participation in management practices, construction stakeholders may develop positive attitudes toward waste minimisation; however, with continuous training from organisations and industry, operatives and professionals’ behaviour towards waste minimisation may change. Furthermore, in addition to teaching new techniques, this study recommends training and education that focuses on changing the values and attitudes of the construction workforce to waste minimisation.

282

7.3.4 Recommendations for Best Practices Best practices are approaches or strategies that have been verified to be effective over time, as they ensure quality standards within an industry. With regard to the study’s findings, it is recommended that the roles and responsibilities of construction professionals, especially those responsible for managing waste, should be stated clearly in contract documents to ensure there is no duplication of responsibilities. Effective collaboration and communication among design team members is encouraged. This may be achieved through a structured organisation and employment of highly efficient design team professionals. To reduce material waste resulting from design variations, efficient review processes should be conducted prior to actual construction. Waste resulting from construction processes due to the nonchalant attitude of operatives should be minimised through close monitoring and supervision of the construction workforce. Contract documents should specify the nature and level of supervision required. This study recommends that waste arising from procurement (such as materials surplus) should be reduced by using strategies for the order and supply of appropriate amounts of materials. In addition, construction firms and professionals should adopt proactive measures in dealing with waste to avoid cost and time overruns.

7.3.5 Recommendations for Research and Development in the NCI Research and development are considered to be the triggers of innovations that could solve problems. Research into efficient design development and technical design measures that mitigate waste would benefit both projects and the environment. The potential benefits to projects include low cost of waste management, minimal waste generation, and more quality time on other aspects of a project rather than waste. The environment would benefit from less pollution as a result of waste-efficient designs. Similarly, green technologies, green procurement, and SC would benefit the environment and all stakeholders. The findings of the study suggest that positive moves to sustainable practices will be achieved through government collaborating with industry. Government may need to provide financial support for research into the potential for reuse and recycling of different construction materials. Research and development of local materials that are sustainable and capable for use as substitutes for imported materials would benefit from funding. Through research, the industry would have opportunities to contribute to sustainable development goals, while the government would benefit from economic development by growing the industry.

283

7.4 Future Research Directions This study has developed a novel CE-CWM framework. It provides significant opportunities to minimise waste at all phases of construction using appropriate design, procurement, construction, 3Rs, and policies approaches that are also effective in reducing environmental pollution and ensuring resource conservation. However, there are areas requiring further investigation. These are highlighted below:

• As suggested in section 6.7.2.5, the framework would benefit from being evaluated to determine its effectiveness for subsequent implementation in the NCI. Additionally, this study may be replicated in other states of Nigeria to compare and generalise findings. • Since other sectors of the construction industry have similar processes, future studies could evaluate and trial the effectiveness of the design, procurement, and construction approaches to material waste minimisation in the civil and electrical engineering sectors. • Contributions of all project stakeholders are vital in minimising material waste. However, respondents in this study were mostly architects, project managers, engineers, builders, foremen, sub-contractors, main contractors, and quantity surveyors. The views of other stakeholders would add depth to the findings. • This research examined construction professionals’ behaviour towards minimising waste and found that their awareness does not inform their perceptions and attitudes. However, their perceptions are influenced by attitudes. This has demonstrated the need to consider the behaviour of each construction project participant and how this affects their decision to minimise waste. • The causes of material waste at the design, procurement, and construction phases have been identified. Future studies should focus on identifying the factors responsible for each cause of waste to determine appropriate strategies for mitigating such factors. Likewise, specific design, procurement, and construction waste minimisation approaches for all types of waste should be investigated. • This study has investigated minimisation measures for construction material waste. Future studies could investigate minimisation measures for other types of construction waste, such as plant, equipment, and labour productivity. • Finally, the framework may be extended to other construction and business sectors, particularly those involved in design and production, such as manufacturing, textiles, and the automobile industry.

284

7.5 Concluding Remarks The study used a concurrent triangulation mixed methods approach to develop a CE waste minimisation framework for the NCI. The data collected shows that waste can be minimised through the circular economy concept, encompassing design approaches (DfWEP, DfDF, DfOC, DfMO and DfRR), green procurement (buy and act green), sustainable construction approaches (strategies, techniques, and operations), 3R principles (reduce, reuse, and recycle), policies (recommend, and require, combined as CEWM policy), and training and education of the construction workforce. Minimising waste at the source of generation is a better alternative to managing waste; this is because it gives value to the project, minimises cost and time overruns, and ensures the environment is free of pollution and able to achieve sustainable development. The resulting CE framework provides a pathway for diverting construction material waste from landfill, and identifies the attitudes and perceptions of the NBCFs that can be explored to develop strategies for waste minimisation, to reduce raw material extraction, and to minimise pollution caused by waste. In addition, the framework offers waste minimisation measures that are appropriate at the design, procurement, and construction phases, in addition to directions for a CE waste minimisation policy to aid implementation of these approaches. Policy, training and education, and legislative measures were identified as appropriate implementation measures for the framework, and there was a high level of willingness by NBCFs to adopt the framework. The benefits of this framework can only accrue if government representatives and policymakers give thoughtful and open-minded consideration to its implementation. Formal and informal educational interventions may also contribute to the acceptance and implementation of the proposed framework.

285

References Abidin, N. Z. (2010). Investigating the awareness and application of sustainable construction concept by Malaysian developers. Habitat International, 34(4), 421-426. Accenture (2015). Circular Advantage: Innovative Business Models and Technology to Create Value without Limits to Growth. United States: Accenture. Available at https://www.accenture.com/t20150523T053139__w__/us- en/_acnmedia/Accenture/Conversion- Assets/DotCom/Documents/Global/PDF/Strategy_6/Accenture-Circular-Advantage- Innovative-Business-Models-Technologies-Value-Growth.pdf Adafin, J., Daramola, O., & Ayodele, E. O. (2010). A Study of Material Control Strategies in Some Selected Construction Firms in Nigeria. Adams, K. (2016). Important factors to consider for applying circular economy in buildings including a focus on reclamation.# Buildcircular learning hub@ Ecobuild 2016, 8–10 March 2016. Adams, K., Osmani, M., Thorpe, T., & Thornback, J. (2017). Circular economy in construction: current awareness, challenges and enablers. Waste and Resource Management, 170(1): 15-24. Adams, O. (1997). Contractor development in Nigeria: perceptions of contractors and professionals. Construction Management & Economics, 15(1), 95-108. Adeagbo, A. (2013). Achieving environmental sustainability (MDG7) in Nigeria: progress so far, challenges and prospects. Academic Journal of Interdisciplinary Studies, 2(6), 47. Adewuyi, T. O., & Odesola, I. A. (2015). Factors affecting material waste on construction sites in Nigeria. Journal of Engineering and Technology (JET), 6(1), 82-99. Adewuyi, T. O., & Odesola, I. A. (2016). Material waste minimisation strategies among construction firms in south-south, Nigeria. International Journal of Sustainable Construction Engineering and Technology, 7(1), 11-29. Adewuyi, T. O., & Otali, M. (2013). Evaluation of causes of construction material waste: Case of River State, Nigeria. Ethiopian Journal of Environmental Studies and Management, 6(6), 746-753. Adewuyi, T. O., Idoro, G. I., & Ikpo, I. J. (2014). Empirical evaluation of construction material waste generated on sites in Nigeria. Civil Engineering Dimension, 16(2), 96-103. Adler, P. A., & Adler, P. (1987). Membership roles in field research (Vol. 6). Sage. Adzroe, E. K., & Ingirige, M. J. B. (2014). Improving the technological capacity of the local contractors through e-business technology transfer-the case of the local Ghanaian contractors. CIB. Agamuthu, P., Khidzir, K. M., & Hamid, F. S. (2009). Drivers of sustainable waste management in Asia. Waste Management & Research, 27(7), 625-633. Agapiou, A. (1998). A review of recent developments in construction operative training in the UK. Construction Management & Economics, 16(5), 511-520. Ahadzie, D., Proverbs, D., & Olomolaiye, P. (2006). A conceptual predictive model for evaluating the performance of project managers in mass house building projects. Ahmed, V., Opoku, A., & Aziz, Z. (Eds.). (2016). Research methodology in the built environment: a selection of case studies. Routledge. Aibinu, A. A., & Jagboro, G. O. (2002). The effects of construction delays on project delivery in Nigerian construction industry. International journal of project management, 20(8), 593-599.

286

Aibinu, A. A., & Odeyinka, H. A. (2006). Construction delays and their causative factors in Nigeria. Journal of construction engineering and management, 132(7), 667-677. Ajanlekoko A.S. (2001). Sustainable housing development in Nigeria: The financial infrastructural implication. In: Proceedings of International Conference on Spatial Information for Sustainable Development, Nairobi, Kenya, pp.1-13. Ajayi, D. D., & Ikporukpo, C. O. (2005). An analysis of Nigeria's environmental vision 2010. Journal of Environmental Policy and Planning, 7(4), 341-365. Ajayi, S. O., & Oyedele, L. O. (2017). Policy imperatives for diverting construction waste from landfill: Experts’ recommendations for UK policy expansion. Journal of Cleaner Production, 147, 57-65. Ajayi, S. O., & Oyedele, L. O. (2018a). Critical design factors for minimising waste in construction projects: A structural equation modelling approach. Resources, Conservation and Recycling, 137, 302-313. Ajayi, S. O., & Oyedele, L. O. (2018b). Waste-efficient materials procurement for construction projects: A structural equation modelling of critical success factors. Waste Management, 75, 60-69. Ajayi, S. O., Oyedele, L. O., Bilal, M., Akinade, O. O., Alaka, H. A., & Owolabi, H. A. (2017). Critical management practices influencing on-site waste minimization in construction projects. Waste management, 59, 330-339. Ajayi, S. O., Oyedele, L. O., Bilal, M., Akinade, O. O., Alaka, H. A., Owolabi, H. A., & Kadiri, K. O. (2015). Waste effectiveness of the construction industry: Understanding the impediments and requisites for improvements. Resources, Conservation and Recycling, 102, 101-112. Ajayi, S., (2017). Design, procurement and construction strategies for minimizing waste in construction projects (Doctoral dissertation, University of the West of England). Ajzen, I. (1985). From intentions to actions: A theory of planned behavior. In Action control (pp. 11-39). Springer, Berlin, Heidelberg. Ajzen, I. (1991). The theory of Planned Behavior. Organizational behavior and human decision processes, 50(2), 179-211. Ajzen, I. (1993). Attitude theory and the attitude-behaviour relation. New Directions in Attitude Measurement, Walter de Gruyter, Berlin, Editions1993. Ajzen, I. (2011). The theory of planned behaviour: reactions and reflections. Taylor & Francis, pp. 1113-1127. Ajzen, I., & Madden, T. J. (1986). Prediction of goal-directed behavior: Attitudes, intentions, and perceived behavioral control. Journal of experimental social psychology, 22(5), 453-474. Akinade, O. O., Oyedele, L. O., Ajayi, S. O., Bilal, M., Alaka, H. A., Owolabi, H. A., ... & Kadiri, K. O. (2017). Design for Deconstruction (DfD): Critical success factors for diverting end-of-life waste from landfills. Waste management, 60, 3-13. Akindelano, L.P. (2018). Review of Nigeria’s Local Content Legislation. Retrieved 11 January 2019 from http://www.akindelano.com/dl/OD%20-%20Local%20Content%20Act.pdf Akinkurolere, O. O., & Franklin, S. O. (2005). Investigation into waste management on construction sites in South Western Nigeria. American Journal of Applied Sciences, 2(5), 980-984. Akintoye, A. (2000). Analysis of factors influencing project cost estimating practice. Construction Management & Economics, 18(1), 77-89.

287

Akpabio, G. T., George, N. J., Akpan, A. E., & Obot, I. (2010). Thermal response of some select wood samples for a passively cooled building design. Arch. Appl. Sci. Res, 2(3), 267-276. Alausa, S. K., Adekoya, B. J., Aderibigbe, J. O., & Nwaokocha, C. F. (2013). Thermal characteristics of laterite-mud and concrete-block for walls in building construction in Nigeria. International Journal of Engineering, 4(4), 8269. Al-Hajj, A., & Hamani, K. (2011). Material waste in the UAE construction industry: Main causes and minimization practices. Architectural engineering and design management, 7(4), 221-235. Alinaitwe, H. M., Mwakali, J. A., & Hansson, B. (2007). Factors affecting the productivity of building craftsmen‐studies of Uganda. Journal of Civil Engineering and Management, 13(3), 169-176. Allen, R. C. (2009). The British industrial revolution in global perspective. Cambridge University Press. Allwood, J. M. (2014). Chapter 30 - Squaring the Circular Economy: The Role of Recycling within a Hierarchy of Material Management Strategies. In E. Worrell & M. A. Reuter (Eds.), Handbook of Recycling (pp. 445-477). Boston: Elsevier. Allwood, J. M. (2016). A bright future for UK steel: A strategy for innovation and leadership through up-cycling and integration. University of Cambridge (Cambridge). Allwood, J. M., Ashby, M. F., Gutowski, T. G., & Worrell, E. (2011). Material efficiency: A white paper. Resources, Conservation and Recycling, 55(3), 362-381. Allwood, J. M., Cullen, J. M., Carruth, M. A., Cooper, D. R., McBrien, M., Milford, R. L. ... & Patel, A. C. (2012). Sustainable materials: with both eyes open (p. 64). Cambridge, UK: UIT Cambridge Limited. Al-Obaidi, K., Wei, S., Ismail, M., & Kam, K. (2017). Sustainable building assessment of colonial shophouses after adaptive reuse in Kuala Lumpur. Buildings, 7(4), 87. Al-Sari, M. I., Al-Khatib, I. A., Avraamides, M., & Fatta-Kassinos, D. (2012). A study on the attitudes and behavioural influence of construction waste management in occupied Palestinian territory. Waste Management & Research, 30(2), 122-136. Aluko, O. (2011). Development Control in Lagos State: an assessment of public compliance to space standards for urban development. African research review, 5(5), 169-184. Alutu, O. E. (2007). Unethical practices in Nigerian construction industry: Prospective engineers’ viewpoint. J. Prof. Issues Eng. Educ. Pract., 10.1061/ (ASCE) 1052- 3928(2007)133:2(84), 84–88. Al-Yami, A. M., & Price, A. D. (2006). A framework for implementing sustainable construction in building briefing project. Ameh, J. O., & Odusami, K. T. (2010). Nigerian building professionals’ ethical ideology and perceived ethical judgement. Construction Economics and Building, 10(3), 1-13. Ameh, O.J., & Itodo, E. D. (2013). Professionals’ views of material wastage on construction sites and cost overruns. Organization, technology & management in construction: an international journal, 5(1), 747-757. American Association for Public Opinion Research Standards Committee (2010). AAPOR report on online panels. Retrieved from https://www.aapor.org/Education- Resources/Reports/Report-on-Online-Panels Andersen, M. (2007). An introductory note on the environmental economics of the circular economy. Sustainability Science, 2(1), 133-140. doi: 10.1007/s11625-006-0013-6

288

Anderson, K. L., Mander, S., Bows, A., Shackley, S., Agnolucci, P., & Ekins, P. (2008). The Tyndall decarbonisation scenarios—Part II: Scenarios for a 60% CO2 reduction in the UK. Energy Policy 36:3764– 3773. Andrews, D. (2015). The circular economy, design thinking and education for sustainability. Local Economy Local Economy, 30(3), 305-315. Angulo, S. C., John, V. M., Kahn, H., & Ulsen, C. (2003). Characterisation and recyclability of construction and demolition waste in Brazil. In WASCON 2003. [San Sebastián]: ISCOWA/INASMET Angulo, S. C., Ulsen, C., John, V. M., Kahn, H., & Cincotto, M. A. (2009). Chemical– mineralogical characterization of C&D waste recycled aggregates from São Paulo, Brazil. Waste management, 29(2), 721-730. Aniekwu, A. (1995). The business environment of the construction industry in Nigeria. Construction Management and Economics, 13(6), 445-455. Ankrah, N. A. (2007). An investigation into the impact of culture on construction project performance. University of Wolverhampton. Ann, T. W., Poon, C. S., Wong, A., Yip, R., & Jaillon, L. (2013). Impact of construction waste disposal charging scheme on work practices at construction sites in Hong Kong. Waste management, 33(1), 138-146. Annunziata, E., Testa, F., Iraldo, F., & Frey, M. (2016). Environmental responsibility in building design: an Italian regional study. Journal of cleaner production, 112, 639-648. Antikainen, M., & Valkokari, K. (2016). A framework for sustainable circular business model innovation. Technology Innovation Management Review, 6(7). Aoe, T. (2007). Eco-efficiency and ecodesign in electrical and electronic products. Journal of Cleaner Production, 15(15), 1406-1414. Arcadis (2017). Top 5 resources. From supply to demand (in Dutch). http://edepot.wur.nl/422138 Accessed 25 Nov 2017 Arditi, D., & Gunaydin, H. M. (1997). Total quality management in the construction process. International Journal of Project Management, 15(4), 235-243. Arge, K. (2005). Adaptable office buildings: theory and practice. Facilities, 23(3/4), 119-127. Arif, M., Syal, M., Florez, L., Castro, D., & Irizarry, J. (2013). Measuring sustainability perceptions of construction materials. Construction Innovation, 13(2), 217-234. Arponen, J.; Granskog, A.; & Pantsar, M. (2015). The opportunities of a circular economy for Finland. Sitra: Helsinki, Finland. ARUP (2016). The circular economy and the Built environment. ARUP, London. Arup and BAM (2017) ‘Circular Business Models for the Built Environment’, https://www.bam.com/sites/default/files/domain- 606/documents/8436_business_models-606-1490949582322972999.pdf Ashby, M. F. (2012). Materials and the environment: eco-informed material choice. Elsevier. Ashcraft, H. W. (2008). Building information modelling: A framework for collaboration. Constr. Law., 28, 5. Ashley, R., Blackwood, D., Butler, D., Davies, J., Jowitt, P., & Smith, H. (2003, March). Sustainable decision making for the UK water industry. In Proceedings of the Institution of Civil Engineers-Engineering Sustainability, 156(1) 41-49. Ashokkumar, D. (2014). Study of quality management in construction industry. International Journal of Innovative Research in Science, Engineering and Technology, 3(1), 36-43. Ashworth, A., & Hogg, K. (2014). Added value in design and construction. Routledge.

289

Ashworth, A., & Perera, S. (2015). Cost studies of buildings. Routledge. Attar, A.A., Gupta, A.K., & Desai, D.B. (2012). A study of various factors affecting labour productivity and methods to improve it. IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE), 1(3): 11– 14. Aulich, T. (2013). The role of effective communication in the construction Industry: a guide for education and health clients. Construction Economics and Building, 13(4), 92-101. Australia Bureau of Statistics (ABS) (2013). The WasteWise Construction Program. Retrieved from http:// http://www.abs.gov.au/ausstats/[email protected]/Previousproducts/1301.0Feature%20Article 252003?opendocument&tabname=Summary&prodno=1301.0&issue=2003&num=& view= Ayangade, J., Wahab, A., & Alake, O. (2009). An Investigation of the Performance of Due Process Mechanism in the Execution of Construction Projects in Nigeria. Civil Engineering Dimension, 11(1), pp. 1-7. Aye, L., Ngo, T., Crawford, R. H., Gammampila, R., & Mendis, P. (2012). Life cycle greenhouse gas emissions and energy analysis of prefabricated reusable building modules. Energy and buildings, 47, 159-168. Azhar, S. (2011). Building information modeling (BIM): Trends, benefits, risks, and challenges for the AEC industry. Leadership and management in engineering, 11(3), 241-252. Babatunde, O. K., & Low, S. P. (2013). Chinese construction firms in the Nigerian construction industry. Habitat International, 40, 18-24. Babatunde, S. O. (2012). Quantitative assessment of construction materials wastage in the Nigerian construction sites. Journal of Emerging Trends in Economics and Management Sciences, 3(3), 238-241. Babbie, E. (2007). The Practice of Social Research (10th ed.). Belmont, CA: Wadsworth. Babbie, E. (2012). The Basics of Social Research: Cengage Learning. Stamford, CT. Bakchan, A., & Faust, K. M. (2019). Construction waste generation estimates of institutional building projects: Leveraging waste hauling tickets. Waste Management, 87, 301-312. Bakker, C., & Hollander, M. (2013). Six Design Strategies for Long Lasting Products in Circular Economy. Retrieved 04 March, 2016, from http://www.theguardian.com/sustainable-business/six-design-strategies-longer- lasting-products Bakker, C., Wang, F., Huisman, J., & Den Hollander, M. (2014). Products that go round: exploring product life extension through design. Journal of Cleaner Production, 69, 10-16. Bala, K., Bello, A., Kolo, B. A., & Bustani, S. A. (2009, September). Factors inhibiting the growth of local construction firms in Nigeria. In Procs 25th ARCOM Conference (pp. 351-359). Balanay, R. M., & Halog, A. (2017). Promoting life cycle thinking for sustainability in the mining sector of the Philippines. The International Journal of Life Cycle Assessment, 22(11), 1864-1874. Balanay, R., & Halog, A. (2016). Charting policy directions for mining’s sustainability with circular economy. Recycling, 1(2), 219-231. Bartl, A. (2015). Withdrawal of the circular economy package: A wasted opportunity or a new challenge?

290

Bastein, A. G. T. M., Roelofs, E., Rietveld, E., & Hoogendoorn, A. (2013). Opportunities for a Circular Economy in the Netherlands. Delft: TNO. Beavis, A. (2015). Remanufacture for the win. The Circular Economy in Organisations— University College London, 11. Becerik-Gerber, B., & Rice, S. (2010). The perceived value of building information modeling in the US building industry. Journal of Information Technology in Construction (ITcon), 15(15), 185-201. Bechtel, N., Bojko, R., & Völkel, R. (2013). Be in the loop: Circular economy & strategic sustainable development. Begum, R. A., Siwar, C., Pereira, J. J., & Jaafar, A. H. (2006). A benefit–cost analysis on the economic feasibility of construction waste minimisation: the case of Malaysia. Resources, conservation and recycling, 48(1), 86-98. Begum, R. A., Siwar, C., Pereira, J. J., & Jaafar, A. H. (2009). Attitude and behavioral factors in waste management in the construction industry of Malaysia. Resources, Conservation and Recycling, 53(6), 321-328. Bekr, G. A. (2014). Study of the causes and magnitude of wastage of materials on construction sites in Jordan. Journal of Construction Engineering, 2014. Benckendorff, P., Edwards, D., Jurowski, C., Liburd, J. J., Miller, G., & Moscardo, G. (2009). Exploring the future of tourism and quality of life. Tourism and Hospitality Research, 9(2), 171-183. Benjamin, D. K., & Meiners, R. E. (2010). Recycling myths revisited. PERC Policy Series No. 47. Benton, D., & Hazell, J. (2015). The Circular Economy in Japan. Retrieved 07 March, 2016, from https://www.the-ies.org/analysis/circular-economy-japan Benton, D., Hazell, J., & Hill, J. (2014). The guide to the circular economy: Capturing value and managing material risk. Oxford: Do Sustainability. Berg, B. L. (2009). Qualitative Research Methods for the Social Sciences. Seventh edition. Allyn and Bacon, Boston MA. Bernard, H. R. (2011). Research methods in anthropology: Qualitative and quantitative approaches. Rowman Altamira. Bertaux, D. (1981). From the life-history approach to the transformation of sociological practice. Biography and society: The life history approach in the social sciences, 29- 45. Bhattacherjee, A. (2012). Social science research: Principles, methods, and practices. Textbooks Collection. Book 3. Bilitewski, B. (2012). The circular economy and its risks. Waste management, 1(32), 1-2. Birat, J. P. (2015). Life-cycle assessment, resource efficiency and recycling. Metallurgical Research & Technology, 112(2), 206. Birkland, T. A. (2015). An introduction to the policy process: Theories, concepts, and models of public policy making. Routledge. Black, T. R. (2001). Understanding social science research: Sage. Blackstone, A. (2012). Inductive or deductive? Two different approaches. Principles of sociological inquiry: Qualitative and quantitative methods, 1. Blomsma, F., & Brennan, G. (2017). The emergence of circular economy: A new framing around prolonging resource productivity. Journal of Industrial Ecology, 21(3), 603- 614.

291

Bocken, N. M., de Pauw, I., Bakker, C., & van der Grinten, B. (2016). Product design and business model strategies for a circular economy. Journal of Industrial and Production Engineering, 33(5), 308-320. Bocken, N. M., Short, S. W., Rana, P., & Evans, S. (2014). A literature and practice review to develop sustainable business model archetypes. Journal of cleaner production, 65, 42- 56. Boix, M., Montastruc, L., Azzaro-Pantel, C., & Domenech, S. (2015). Optimization methods applied to the design of eco-industrial parks: a literature review. Journal of Cleaner Production, 87, 303-317. Bolden, J., Abu-Lebdeh, T., & Fini, E. (2013). Utilization of recycled and waste materials in various construction applications. American Journal of Environmental Science, 9(1), 14-24. Bonilla, S. H., Almeida, C. M., Giannetti, B. F., & Huisingh, D. (2010). The roles of cleaner production in the sustainable development of modern societies: an introduction to this special issue. Journal of Cleaner Production, 18(1), 1-5. Boons, F., & Lüdeke-Freund, F. (2013). Business models for sustainable innovation: state-of- the-art and steps towards a research agenda. Journal of Cleaner production, 45, 9-19. Bossink, B. A. G., & Brouwers, H. J. H. (1996). Construction waste: quantification and source evaluation. Journal of construction engineering and management, 122(1), 55-60. Botsman, R., & Rogers, R. (2010). What’s mine is yours: The rise of collaborative consumption. Collins. Boulding, K. E. (1966). The economics of the coming spaceship earth. Environmental Quality Issues in a Growing Economy. Bouma, G. (2000). Ethics in human research. The Research Process, 4, 190-202. Bourguignon, D. (2016). Closing the loop: New circular economy package. European Parliamentary Research Service, 9. Bovea, M., & Pérez-Belis, V. (2012). A taxonomy of ecodesign tools for integrating environmental requirements into the product design process. Journal of Cleaner Production, 20(1), 61-71. Bowen, G. A. (2008). Naturalistic inquiry and the saturation concept: a research note. Qualitative research, 8(1), 137-152. Braungart, M., McDonough, W., & Bollinger, A. (2007). Cradle-to-cradle design: creating healthy emissions–a strategy for eco-effective product and system design. Journal of cleaner production, 15(13-14), 1337-1348. Braunschweig, G. (2010). Too many Policies and Procedures can be counterproductive. Retrieved 8 December 2018 from https://www.erpsoftwareblog.com/2010/08/too- many-policies-and-procedures-can-be-counterproductive/ Brierley, J. A. (2017). The role of a pragmatist paradigm when adopting mixed methods in behavioural accounting research. International Journal of Behavioural Accounting and Finance, 6(2), 140-154. Broman, G. I., & Robèrt, K. H. (2017). A framework for strategic sustainable development. Journal of Cleaner Production, 140, 17-31. Brown, G., & Stone, L. (2007). Cleaner production in New Zealand: taking stock. Journal of Cleaner Production, 15(8-9), 716-728. Brown, M. T., & Buranakarn, V. (2003). Emergy indices and ratios for sustainable material cycles and recycle options. Resources, Conservation and Recycling, 38(1), 1-22.

292

Brown, Z. S., & Johnstone, N. (2014). Better the devil you throw: Experience and support for pay-as-you-throw waste charges. Environmental Science & Policy, 38, 132-142. Brunner, P. H., & Rechberger, H. (2004). Practical Handbook of Material Flow Analysis, Lewis Publishers, Boca Raton, FL,-p. 336. Bryman, A. (2012). Sampling in qualitative research. Social research methods, 4, 415-429. Bryman, A. (2015). Social research methods: Oxford university press. Bryman, A., & Bell, E. (2007). Business research strategies. Business research methods. Brynard, P. A. (2009). Mapping the factors that influence policy implementation. Burns, A. C., & Bush, R. F. (2006). Marketing research with SPSS 13.0 student version for windows. Cagno, E., Trucco, P., & Tardini, L. (2005). Cleaner production and profitability: analysis of 134 industrial pollution prevention (P2) project reports. Journal of Cleaner Production, 13(6), 593-605. Cahn, M. A. (2012). Institutional and Non-institutional Actors in the Policy Process. Public Policy: The Essential Readings, 2, 199-206. Calogirou, C., Sørensen, S., Bjørn Larsen, P., & Alexopoulou, S. (2010). SMEs and the environment in the European Union. PLANET SA and Danish Technological Institute, Published by European Commission, DG Enterprise and Industry. Castellani, V., Sala, S., & Mirabella, N. (2015). Beyond the throwaway society: A life cycle‐ based assessment of the environmental benefit of reuse. Integrated environmental assessment and management, 11(3), 373-382. Catalli, V., & Williams, M. (2001). Technical.-How Ottawa's new Mountain Equipment Co- op store was designed for disassembly. Canadian Architect, 46(1), 29-30. CCICED. (2008). Circular Economy Promotion Law of the People's Republic of China. China: CCICED Retrieved from http://www.bjreview.com.cn/document/txt/2008- 12/04/content_168428.htm Cha, H. S., Kim, J., & Han, J. Y. (2009). Identifying and assessing influence factors on improving waste management performance for building construction projects. Journal of construction engineering and management, 135(7), 647-656. Chang, R. D., Zuo, J., Zhao, Z. Y., Soebarto, V., Lu, Y., Zillante, G., & Gan, X. L. (2018). Sustainability attitude and performance of construction enterprises: A China study. Journal of Cleaner Production, 172, 1440-1451. Charonis, G.-K. (2012). Degrowth, steady state economics and the circular economy: three distinct yet increasingly converging alternative discourses to economic growth for achieving environmental sustainability and social equity. Paper presented at the World Economic Association Sustainability Conference. Chartered Institute of Waste Management, C. (2014). The Circular Economy: what does it mean for the waste and resource management sector? England: Chartered Institute of Waste Management, UK. Chen, J. Z. (2009). Material flow and circular economy. Systems Research and Behavioral Science: The Official Journal of the International Federation for Systems Research, 26(2), 269-278. Chen, W. Q., & Graedel, T. E. (2012). Dynamic analysis of aluminium stocks and flows in the United States: 1900–2009. Ecological Economics, 81, 92-102. Chen, Z., Li, H., & Wong, C. T. (2002). An application of bar-code system for reducing construction wastes. Automation in Construction, 11(5), 521-533.

293

Cheng, J. C., & Ma, L. Y. (2013). A BIM-based system for demolition and renovation waste estimation and planning. Waste management, 33(6), 1539-1551. Chertow, M. R. (2000). Industrial symbiosis: literature and taxonomy. Annual review of energy and the environment, 25(1), 313-337. Chinyio, E. A., & Olomolaiye, P. O. (1999). A needs based methodology for classifying construction clients and selecting contractors-a rejoinder. Construction Management & Economics, 17(4), 413-417. Chong, W. K., & Hermreck, C. (2011). Modeling the use of transportation energy for recycling construction steel. Clean Technologies and Environmental Policy, 13(2), 317-330. CIB (2004): Globalization and Construction: Meeting the Challenges; Reaping the Benefits. Write up for the Call for Papers. Available at http://www.sce.ait.ac.th/GC2004 CIRAIG (International Reference Center for the Life Cycle of Products Processes and Services) (2015). Circular economy: A critical literature review of concepts. Montreal, Québec, Canada: Bibliothèque et Archives nationales du Quebec (BAnQ). Circle Economy (2012). The Circular Design Program. Retrieved 03 March, 2016, from http://www.circle-economy.com/projects/sector/circular-design-program/ Circulair, N. (2015). The Potential for High Value Reuse in a Circular Economy. Clauss, T. (2017). Measuring business model innovation: conceptualization, scale development, and proof of performance. R&D Management, 47(3), 385-403. Clift, R. (2004). Metrics for supply chain sustainability. In Technological choices for sustainability (pp. 239-253). Springer, Berlin, Heidelberg. Cochran, K. M., & Townsend, T. G. (2010). Estimating construction and demolition debris generation using a materials flow analysis approach. Waste Management, 30(11), 2247-2254. Cochran, W. G. (1983). G. m. Cox. 1957. Experimental designs. Wiley Publications in Applied Statistics, New York. Coffey, M. (1999). Cost-effective systems for solid waste management. Waterlines, 17(3), 23- 24. Cohen, J. (1988). Statistical power analysis for the behavioural sciences (2nd ed.). Hillsdale, NJ: Erlbaum. Cohen, L., Manion, L., & Morrison, K. (2000). Research in education. Routledge Falmer, London. Cohen-Rosenthal, E. (2000). A walk on the human side of industrial ecology. American Behavioral Scientist, 44(2), 245-264. Construction Products Association (2016). Knowledge Resource for Circular Economy Thinking in Construction. Retrieved from https://www.constructionproducts.org.uk/media/177748/gcb-circular-economy-april- 2016-v3.pdf Corbey, S., Cullen, J. M., Sansom, M., & Fishwick, R. (2016). Overcoming the Barriers to Steel Re-use in Construction. BuildCircular learning hub, EcoBuild 2016. Council, G. (2010). Report of the research study on the current status and direction for green purchasing in Hong Kong. Green Council. Coventry, S., Shorter, B., Kingsley, M. (2001). Demonstrating Waste Minimisation Benefits in Construction. In: CIRIA C536. Construction Industry Research and Information Association (CIRIA), London, United Kingdom.

294

Crano, W. D., & Prislin, R. (2006). Attitudes and persuasion. Annu. Rev. Psychol., 57, 345- 374. Crawford, R. H., Mathur, D., & Gerritsen, R. (2017). Barriers to improving the environmental performance of construction waste management in remote communities. Procedia engineering, 196, 830-837. Creswell, J. W. (2003). A framework for design. Research design: Qualitative, quantitative, and mixed methods approaches, 9-11. Creswell, J. W. (2007). Five qualitative approaches to inquiry. Qualitative inquiry and research design: Choosing among five approaches, 2, 53-80. Creswell, J. W. (2013). Educational research: Planning, conducting, and evaluating. W. Ross MacDonald School Resource Services Library. Creswell, J. W. (2014a). A concise introduction to mixed methods research. Sage Publications. Creswell, J. W. (2014b). The selection of a research approach. Research design: Qualitative, quantitative, and mixed methods approaches, 3-24. Creswell, J. W., & Clark, V. L. P. (2017). Designing and Conducting Mixed Methods Research. Sage publications. Creswell, J. W., & Plano Clark, V. L. (2007). Designing and Conducting Mixed Methods Research. Thousand Oaks USA: SAGE. Creswell, J. W., & Plano Clark, V. L. (2011). Choosing a mixed methods design. Designing and conducting mixed methods research, 2, 53-106. Creswell, J. W., & Poth, C. N. (2017). Qualitative inquiry and research design: Choosing among five approaches. Sage publications. Creswell, J. W., Plano Clark, V. L., Gutmann, M. L., & Hanson, W. E. (2003). Advanced mixed methods research designs. Handbook of mixed methods in social and behavioral research, 209, 240. Crouch, M., & McKenzie, H. (2006). The logic of small samples in interview-based qualitative research. Social science information, 45(4), 483-499. Crowther, G., & Gilman, T. (2014). Towards the circular economy: Accelerating the scale-up across global supply chains, World Economic Forum Report, Geneva. Retrieved December 16, 2016, from http://www.weforum.org/reports/towards-circular-economy- accelerating-scale-across-global-supply-chains da Rocha, C. G., & Sattler, M. A. (2009). A discussion on the reuse of building components in Brazil: An analysis of major social, economical and legal factors. Resources, Conservation and Recycling, 54(2), 104-112. Dachowski, R., & Kostrzewa, P. (2016). The use of waste materials in the construction industry. Procedia engineering, 161, 754-758. Dahiru, D., Dania, A. A., & Adejoh, A. (2014). An investigation into the prospects of green building practice in Nigeria. Journal of Sustainable Development, 7(6), 158. Dahlbo, H., Bachér, J., Lähtinen, K., Jouttijärvi, T., Suoheimo, P., Mattila, T. ... & Saramäki, K. (2015). Construction and demolition waste management–a holistic evaluation of environmental performance. Journal of Cleaner Production, 107, 333-341. Dahlén, L., & Lagerkvist, A. (2010). Pay as you throw: strengths and weaknesses of weight- based billing in household waste collection systems in Sweden. Waste management, 30(1), 23-31. Dainty, A. R., & Brooke, R. J. (2004). Towards improved construction waste minimisation: a need for improved supply chain integration? Structural Survey, 22(1), 20-29.

295

Dajian, Z. (2008). Background, pattern and policy of China for developing circular economy. Chinese Journal of Population Resources and Environment, 6(4), 3-8. Dalian Municipality (2004). Guidelines for Developing Green Building in Dalian, Official Documents. (In Chinese). Dalian Municipality (2007). Dalian Action Plans for Energy Saving and Emission Reduction. Unpublished Report, August 2007. (In Chinese) Daly, F. (2015). Getting Things Done. Collaborating across Departments and Sectors. The Circular Economy in Organisations - University College London, London. Damen, M. A. (2012). A resource passport for a circular economy: An assessment of the possible content and format of a resources passport in order to successfully contribute to the achievement of the circular economy. Unpublished master’s thesis, University of Utrecht, Utrecht, Netherlands. Dania, A. A. (2016). Sustainable Construction at the Firm Level: Case Studies from Nigeria. (Doctoral Dissertation, University of Reading). Dania, A. A., Kehinde, J., & Bala, K. (2007). A study of construction material waste management practices by construction firms in Nigeria. Building Research Reports series, Caledonia University, Scotland UK, 121-129. Dania, A. A., Larsen, G. D., & Yao, R. (2013). Sustainable Construction in Nigeria: Understanding Firm Level Perspectives. Paper presented at the Sustainable Building Conference, Coventry University. Dantata, S. (2007). General overview of the Nigerian construction industry (Doctoral dissertation, Massachusetts Institute of Technology). Danthurebandara, M., Van Passel, S., Nelen, D., Tielemans, Y., & Van Acker, K. (2012). Environmental and socio-economic impacts of landfills. In Linnaeus ECO-TECH, 26- 28 November 2012, Kalmar, Sweden. Dantong J.S.D., Lekjeb R.S., & Dessah, E. (2011). Investigating the Most Effective Training for Construction Craftsmen that will Optimize Productivity in the Nigeria Construction Industry. Davidson, G. (2011). Waste management practices: literature review. Dalhousie University, Office of Sustainability, 1-59. de Figueirêdo Lopes Lucena, L. C., Thomé Juca, J. F., Soares, J. B., & Portela, M. G. (2013). Potential uses of sewage sludge in highway construction. Journal of Materials in Civil Engineering, 26(9), 04014051. de Guzmán Báez, A., Sáez, P. V., del Río Merino, M., & Navarro, J. G. (2012). Methodology for quantification of waste generated in Spanish railway construction works. Waste Management, 32(5), 920-924. De Vaus, D. (2013). Surveys in social research. Routledge. De Vaus, D. (2014). Diversity and change in Australian families: Statistical profiles. Australian Institute of Family Studies. 2004. Dearing, J. W. (2009). Applying diffusion of innovation theory to intervention development. Research on social work practice, 19(5), 503-518. DEFRA (2013) Waste Management Plan for England. DEFRA, London, UK. del Río Merino, M., & Astorqui, J. S. C. (2009). Finite element simulation to design constructive elements: An application to light gypsum plaster for partitions. Construction and Building Materials, 23(1), 14-27.

296 den Hollander, M. C., Bakker, C. A., & Hultink, E. J. (2017). Product design in a circular economy: Development of a typology of key concepts and terms. Journal of Industrial Ecology, 21(3), 517-525. Department of the Environment Food and Rural Affairs (DEFRA) (2011). Government review of waste strategy for England 2007. DEFRA, London. Desai, A., & Mital, A. (2003). Evaluation of disassemblability to enable design for disassembly in mass production. International Journal of Industrial Ergonomics, 32(4), 265-281. Desai, A., & Mital, A. (2005). Incorporating work factors in design for disassembly in product design. Journal of Manufacturing Technology Management, 16(7), 712-732. Deutz, P., & Gibbs, D. (2008). Industrial ecology and regional development: eco-industrial development as cluster policy. Regional Studies, 42(10), 1313-1328. Diabat, A., & Govindan, K. (2011). An analysis of the drivers affecting the implementation of green supply chain management. Resources, Conservation and Recycling, 55(6), 659- 667. Dickie, I., & Howard, N. (2000). Assessing environmental impacts of construction: Industry consensus, BREEAM and UK Ecopoints. Watford, UK: Building Research Establishment. Dimitrova, V., Lagioia, G., & Gallucci, T. (2007). Managerial factors for evaluating eco- clustering approach. Industrial Management & Data Systems, 107(9), 1335-1348. Ding, G. K. (2008). Sustainable construction - The role of environmental assessment tools. Journal of environmental management, 86(3), 451-464. Diyamandoglu, V., & Fortuna, L. M. (2015). Deconstruction of wood-framed houses: Material recovery and environmental impact. Resources, Conservation and Recycling, 100, 21- 30. Dooley, K. E. (1999). Towards a holistic model for the diffusion of educational technologies: An integrative review of educational innovation studies. Educational Technology & Society, 2(4), 35-45. Dorn, T., Nelles, M., & Flamme, S. (2010). Circular economy in China. Paper presented at the ISWA World Congress. Doroudiani, S., & Omidian, H. (2010). Environmental, health and safety concerns of decorative mouldings made of expanded polystyrene in buildings. Building and Environment, 45(3), 647-654. Dror, Y. (2017). Public policy making reexamined. Routledge. Drury, C. G. (1995). Methods for direct observation of performance. In J. R. Wilson & E. N. Corlett (Eds.), Evolution of human work; a practical ergonomics methodology (2nd ed., pp. 45–68). Philadelphia: Taylor and Francis. Du Plessis, C. (2001). Sustainability and sustainable construction: the African context. Building Research & Information, 29(5), 374-380. Du Plessis, C. (2002). Agenda 21 for sustainable construction in developing countries. CSIR Report BOU E, 204. Du Plessis, C. (2007). A strategic framework for sustainable construction in developing countries. Construction Management and Economics, 25(1), 67-76. Dulaimi, M. F., Ling, F. Y., & Bajracharya, A. (2003). Organizational motivation and interorganizational interaction in construction innovation in Singapore. Construction Management and economics, 21(3), 307-318.

297

Duran, X., Lenihan, H., & O’Regan, B. (2006). A model for assessing the economic viability of construction and demolition waste recycling—the case of Ireland. Resources, Conservation and Recycling, 46(3), 302-320. Durdyev, S., & Mbachu, J. (2011). On-site labour productivity of New Zealand construction industry: Key constraints and improvement measures. Construction Economics and Building, 11(3), 18-33. Easterby-Smith, M., Thorpe, R., & Jackson, P. R. (2012). Management research. Sage. Eastman, C., Teicholz, P., Sacks, R., & Liston, K. (2011). BIM handbook: A guide to building information modeling for owners, managers, designers, engineers and contractors. John Wiley & Sons. Economics. Edmonds, G. A., & Miles, D. W. J. (1984). Foundations for change. Intermediate Technology Publication. Ehrenfeld, J. (2004). Industrial ecology: a new field or only a metaphor? Journal of cleaner production, 12(8-10), 825-831. Ekanayake, L. L., & Ofori, G. (2004). Building waste assessment score: design-based tool. Building and Environment, 39(7), 851-861. Ekanayake, L.L., & Ofori, G. (2000). Construction material waste source evaluation. In: Proceedings of the Second Southern African Conference on Sustainable Development in the Built Environment: Strategies for a Sustainable Built Environment, Pretoria, South Africa. El-Haggar, S. M. (2007). Sustainability of construction and demolition waste management. Sustainable Industrial Design and Waste Management Cradle-to-cradle for Sustainable Development, 261-292. Ellen MacArthur Foundation (EMF) (2013a). Towards Circular Economy: Economic and business rationale for an accelerated transition (Vol. 1). United Kingdom: Ellen MacArthur Foundation. Ellen MacArthur Foundation (EMF) (2013b). Towards the Circular Economy: Opportunities for the consumer goods sector (Vol. 2). United Kingdom: Ellen MacArthur Foundation. Ellen MacArthur Foundation (EMF) (2015a). Towards a circular economy - Business rationale for an accelerated transition. Isle of Wight, UK: Ellen MacArthur Foundation. Ellen MacArthur Foundation (EMF) (2015b). Delivering the circular economy - A toolkit for policy makers. Isle of Wight, UK: Ellen MacArthur Foundation. Ellen MacArthur Foundation (EMF) (2015c). Growth within - A circular economy vision for a competitive Europe. Isle of Wight, UK: Ellen MacArthur Foundation. Ellen MacArthur Foundation (EMF) (2016) Home Page. Retrieved from www.ellenmcarthurfoundation.org/programmes Ellen MacArthur Foundation (EMF) (2017) Priority Research Agenda. Available at https://www.ellenmacarthurfoundation.org/assets/downloads/higher- education/EMF_Priority-Research-Agenda-copy.pdf Ellingham, I., & Fawcett, W. (2007). New generation whole-life costing: Property and construction decision-making under uncertainty. Routledge. Elnaas, H., Gidado, K., & Philip, A. P. (2014). Factors and drivers effecting the decision of using off-site manufacturing (OSM) systems in house building industry. Journal of Engineering, Project, and Production Management, 4(1), 51-58.

298

Emmanuel, A. J., Ibrahim, A. D., & Adogbo, K. J. (2014). An assessment of professionals' perception of the sustainability performance of infrastructure projects in Nigeria. Journal of Construction Project Management and Innovation, 4(Supplement 1), 912-932. Emuze, F. A. (2011). Performance improvement in South African construction (Doctoral dissertation, Nelson Mandela Metropolitan University). Eneh, O. C., & Agbazue, V. C. (2011). Protection of Nigeria's environment: A critical policy review. Journal of Environmental Science and Technology, 4(5), 490-497. Environmental Performance Index (2018). Global Metrics for the Environment. Retrieved 7 January 2019 from: https://epi.envirocenter.yale.edu/ Environmental Protection Department (2007). Comment on the Report entitled “Relative Significance of Local vs Regional Sources: Hong Kong's Air Pollution”. Environmental Protection Department, HKSAR Government. Retrieved 30 April 2018 from http://www.epd.gov.hk/epd/textonly/english/news_events/other/comments_070321b.h tml Environmental Protection Department (EPD) (2018). Hong Kong Waste Treatment and Disposal Statistics. Retrieved from https://www.epd.gov.hk/epd/english/environmentinhk/waste/data/stat_treat.html EPA, U. (1998). Field applications of in situ remediation technologies: chemical oxidation. Washington DC, EPA. EPA, U. (2000). National air pollutant emission trends 1900–1998. US Environmental Protection Agency. Ernst and Young Accountants, L. (2015). Are you ready for the Circular Economy? The necessity of an Integrated Approach. The Netherlands. Ernzer, M., & Wimmer, W. (2002). From environmental assessment results to Design for Environment product changes: an evaluation of quantitative and qualitative methods. Journal of Engineering Design, 13(3), 233-242. ESA (Environmental Services Association) (2013). Going for Growth: A Practical Route to a Circular Economy, Retrieved 16 November 2015 from http://tinyurl.com/nlmukxc Esa, M. R., Halog, A., & Rigamonti, L. (2017). Developing strategies for managing construction and demolition wastes in Malaysia based on the concept of circular economy. Journal of Material Cycles and Waste Management, 19(3), 1144-1154. Esin, T., & Cosgun, N. (2007). A study conducted to reduce construction waste generation in Turkey. Building and Environment, 42(4), 1667-1674. Esposito, M., Tse, T., & Soufani, K. (2016). How businesses can support a circular economy. Harvard Business Review, 1. Esposito, M., Tse, T., & Soufani, K. (2017). Is the circular economy a new fast‐expanding market? Thunderbird International Business Review, 59(1), 9-14. Esposito, M., Tse, T., & Soufani, K. (2018). Introducing a circular economy: new thinking with new managerial and policy implications. California Management Review, 60(3), 5-19. Etxeberria, M., Vázquez, E., Marí, A., & Barra, M. (2007). Influence of amount of recycled coarse aggregates and production process on properties of recycled aggregate concrete. Cement and concrete research, 37(5), 735-742. European Commission (EC) (2001). Promoting a European Framework for Corporate Social Responsibility: Green Paper: Office for Official Publications of the European Communities.

299

European Commission (EC) (2008). Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on waste and repealing certain Directives. Official Journal of the European Union, 312(3). European Commission (EC) (2011). Roadmap to a resource efficient Europe. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the regions, COM (2011) 571. Brussels: European Commission (EC). European Commission (EC) (2012). Ecodesign your future - How ecodesign can help the environment by making products smarter. http://ec.europa.eu/DocsRoom/documents/5187/attachments/1/translations/en/renditio ns/native. Accessed December 2015. European Commission (EC) (2014a). Towards a Circular Economy: A Zero Waste Programme for Europe. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. Brussels: European Commission. European Commission (EC) (2014b). Progress report on the roadmap to a resource efficient Europe. Accompanying the document: COM (2014) 398 final/2. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions, SWD (2014) 206 final/2. Brussels: European Commission (EC). European Commission (EC) (2014c). Scoping study to identify potential circular economy actions, priority sectors, material flows and value chains. Brussels. European Commission (EC) (2015). Closing the loop—An EU action plan for the circular economy. Communication from the com-mission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions, COM (2015) 614. Brussels: European Commission (EC) European Commission (EC) (2017). The role of waste-to-energy in the circular economy. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. European Construction Industry Federation (FIEC) (2016). Circular Economy Action Plan welcomed by FIEC. A position paper 18.01.2016. Retrieved from http://www.fiec.eu/en/cust/documentview.aspx?UID=f579414a-4f2f-4b39-99cd- ee6746dd9d0a European Environment Agency (EEA). (2016). Mitigating climate change, greenhouse gas emissions. Retrieved from http://www.eea.europa.eu/soer-2015/countries- comparison/climate-change-mitigation European Environmental Bureau (2014). Advancing Resource Efficiency in Europe: Indicators and waste policy scenarios to deliver a resource efficient and sustainable Europe. Brussels: European Environmental Bureau. European Environmental Bureau (2015). Delivering resource-efficient products: How ecodesign can drive a circular economy in Europe. Brussels: European Environmental Bureau. European Joint Research Centre (JRC) (2011) Institute for Environment and Sustainability (IES), life cycle website: http://lct.jrc.ec.europa.eu; continuously updated info on how to get access to the guidelines being developed by the JRC can be found at: http://lct.jrc.ec.europa.eu/assessment/projects

300

European Union (2008). Directive 2008/98/EC of the European Parliament and the Council of 19 November 2008 on Waste and Repealing Certain Directives. Official Journal of the European Union L, 312, 22.11 Eurostat (2014). Waste Statistics in Europe. Retrieved 10 January 2017 from www.epp.eurostat.ec.europa.eu Eurostat (2018): Generation of waste by waste category, hazardousness and NACE Rev. 2 activity. Retrieved from http://appsso.eurostat.ec.europa.eu/nui/show.do?dataset=env_wasgen&lang=en Eze, E. C., Seghosime, R., Eyong, O. P., & Loya, O. S. (2017). Assessment of materials waste in the construction industry: A view of Construction Operatives, Tradesmen and Artisans in Nigeria. The International Journal of Engineering and Science, 6(4), 32-47. Ezeifedi, C. (2012). Challenges Facing Indigenous Building Construction Companies in Nigeria. Retrieved 05 March, 2016 from www.bioclimaenergetics.com Ezugwu, A. (2014) Applying Local Content Policy in Construction Industry. Retrieved 5 February 2019 from https://realnewsmagazine.net/business/applying-local-content- policy-in-construction-industry/ Fabrigar L. (2004) Social influence; PSYC 399-2004. Retrieved 12 January 2019, from http://www.psyc.queensu.ca/courses/psyc399/ Fadeyi, M. O., Jallow, A. K., Anumba, C., & Dulaimi, M. (2013). Process Management Approach for Achieving Total Building Performance: Essential Requirements for Sustainable Construction. In AEI 2013: Building Solutions for Architectural Engineering (pp. 174-183). Fahmy, A., Hassan, T. M., & Bassioni, H. (2014). Improving RCPSP solutions quality with Stacking Justification–Application with particle swarm optimization. Expert Systems with Applications, 41(13), 5870-5881. Faniran, O. O., & Caban, G. (1998). Minimizing waste on construction project sites. Engineering, construction and architectural management, 5(2), 182-188. Fapohunda, J. A., & Stephenson, P. (2011). Knowledge, Attitude, and Perception (KAP) of Construction Participants towards Resource Waste in the Construction Industry. The Pacific Journal of Science and Technology, 12(2), 284-299. Faraud, C. (2016). Circular Economy Strategy at a City Level. BuildCircular learning hub, EcoBuild 2016. Federal Environmental Protection Agency (1989). National policy on the environment, pp. 22. Federal Government of Nigeria (2012). Nigeria's path to Sustainable Development through Green Economy Country Report to the Rio+20 Summit. Abuja. Federal Ministry of Lands, Housing and Urban Development (2014). Nigeria National Report for United Nations Conference on Housing and Urban Development (HABITAT III). Abuja: FMLHUD Federal Republic of Nigeria (2004). Laws of the Federal Republic of Nigeria. Federal Government Press: Lagos. Federal Republic of Nigeria (2006). National Building Code. Cape Town, South Africa: LexisNexis Butterworth. Fellows, R. F., Langford, D., Newcombe, R., & Urry, S. (2009). Construction management in practice: John Wiley & Sons. Feng, W. J., Mao, Y. R., Chen, H., & Chen, C. (2007). Study on development pattern of circular economy in chemical industry parks in China. Modern Chemical Industry, 27(3), 7.

301

Fereday, J., & Muir-Cochrane, E. (2006). Demonstrating rigor using thematic analysis: A hybrid approach of inductive and deductive coding and theme development. International journal of qualitative methods, 5(1), 80-92. Fernz, B., Hawkins, J., Matthews, P., & Wells, J. (2013). Policy review on the local content bill for the Nigerian construction industry. Final report, Engineers against Poverty, available at: www.engineersagainstpoverty.org/documentdownload.Axd Ferreira, J., Pinheiro, M. D., & De Brito, J. (2015). Economic and environmental savings of structural buildings refurbishment with demolition and reconstruction-A Portuguese benchmarking. Journal of Building Engineering, 3, 114-126. Field, A. (2005). Discovering statistics through SPSS. Sage: London. Fieldhouse, E. (2015). Using gamification to change behaviours for ever. The Circular Economy in Organisations—University College London, London, 11. Fielding, N. G. (2012). Triangulation and mixed methods designs: Data integration with new research technologies. Journal of Mixed Methods Research, 6(2), 124-136. Fink, A. (2003). The Survey Handbook (2nd ed. Vol. 1). Thousand Oaks, CA: Sage Publications. Finland's Independence Celebration Fund (FICF) and McKinsey (2014). Kiertotalouden Mahdollisuudet Suomelle (the Possibilities of a Circular Economy for Finland). SITRA, Helsinki, Finland. Fischer‐Kowalski, M., & Hüttler, W. (1998). Society's Metabolism: The Intellectual History of Materials Flow Analysis, Part II, 1970‐1 998. Journal of industrial ecology, 2(4), 107- 136. Flanagan, R., & Jewell, C. (2008). Whole life appraisal for construction. John Wiley & Sons. Flick, U. (Ed.). (2013). The SAGE handbook of qualitative data analysis. Sage. Flick, U., Garms-Homolova, V., Herrmann, W. J., Kuck, J., & Röhnsch, G. (2012). “I Can’t Prescribe Something Just Because Someone Asks for It...” Using Mixed Methods in the Framework of Triangulation. Journal of Mixed Methods Research, 6(2), 97-110. Formoso, C. T., Isatto, E. L., & Hirota, E. H. (1999). Method for waste control in the building industry. In Proceedings IGLC 7, p. 325. Formoso, C. T., Soibelman, L., De Cesare, C., & Isatto, E. L. (2002). Material waste in building industry: main causes and prevention. Journal of construction engineering and management, 128(4), 316-325. Frankfort-Nachmias, C., & Nachmias, D. (1996). Index construction and scaling methods: Research methods in the social sciences. London: St Martin’s Press. Fuller, S. (2010). Life-Cycle Cost Analysis (LCCA). National Institute of Standards and Technology (NIST) (on line). Fussell, T., Blismas, N., Wakefield, R., Bullen, P., Sher, W., Bird, R., & Brotherwood, S. (2007). Offsite Manufacture in Australia. Cooperative Research Centre for Construction Innovation: Brisbane, Australia. p. 82. Galle, W., De Temmerman, N., & De Meyer, R. (2017). Integrating scenarios into life cycle assessment: Understanding the value and financial feasibility of a demountable building. Buildings, 7(3), 64. Gallup J. (2018). Top-Down versus Bottom-up: Two approaches to Sustainability. Retrieved January 12, 2019 from https://sustainability.wisc.edu/top-down-bottom-up- sustainability/

302

Gamage, I. S. W., Osmani, M., & Glass, J. (2009). An investigation into the impact of procurement systems on waste generation: the contractors' perspective. Proceedings of the Association of Researchers in Construction Management (ARCOM), Nottingham, UK, 103-104. Gan, X., Zuo, J., Ye, K., Skitmore, M., & Xiong, B. (2015). Why sustainable construction? Why not? An owner's perspective. Habitat international, 47, 61-68. Gangolells, M., Casals, M., Forcada, N., & Macarulla, M. (2014). Analysis of the implementation of effective waste management practices in construction projects and sites. Resources, conservation and recycling, 93, 99-111. Garas, G. L., Anis, A. R., & El Gammal, A. (2001). Materials waste in the Egyptian construction industry. Proceedings IGLC-9, Singapore, 86. Garba, A., Olaleye, Y. O. & Jibrin, N. S. (2016). Material Resources Optimization for Sustainable Construction in Nigeria. Journal of Engineering and Architecture, June, 4 (1), pp. 33-47, DOI: 10.15640/jea.v4n1a3 Garland, R. (1991). The mid-point on a rating scale: Is it desirable. Marketing bulletin, 2(1), 66-70. Gaspar, M., Julião, J., & Tjahjono, B. (2018). Circular Economy in a Multiple Helix Perspective: A Review. Economics, Management and Marketing (MAC-EMM 2018), 121. Gaspar, P. L., & Santos, A. L. (2015). Embodied energy on refurbishment vs. demolition: A southern Europe case study. Energy and Buildings, 87, 386-394. Gayathri, N., Himal, S. J., & Ranadewa, K. A. T. (2013). BIM and future Quantity Surveying practice in Sri Lankan Construction Industry. In The 2nd World Construction Symposium (pp. 14-15). Geisendorf, S., & Pietrulla, F. (2018). The circular economy and circular economic concepts— a literature analysis and redefinition. Thunderbird International Business Review, 60(5), 771-782. Geissdoerfer, M., Savaget, P., Bocken, N. M., & Hultink, E. J. (2017). The Circular Economy– A new sustainability paradigm? Journal of cleaner production, 143, 757-768. Geldermans, R. J., & Rosen-Jacobsen, L. (2015). Circular material & product flows in buildings (AET Architecture and The Built Environment, Trans.). Delft: Delft University of Technology. Geng, Y., & Cote, R. (2004). Applying industrial ecology in rapidly industrializing Asian countries. The International Journal of Sustainable Development & World Ecology, 11(1), 69-85. Geng, Y., Fu, J., Sarkis, J., & Xue, B. (2012). Towards a national circular economy indicator system in China: an evaluation and critical analysis. Journal of Cleaner Production, 23(1), 216-224. doi: http://dx.doi.org/10.1016/j.jclepro.2011.07.005 Geng, Y., Zhang, P., Ulgiati, S., & Sarkis, J. (2010). Emergy analysis of an industrial park: The case of Dalian, China. Science of the Total Environment, 408(22), 5273-5283. doi: http://dx.doi.org/10.1016/j.scitotenv.2010.07.081 Geng, Y., Zhu, Q., Doberstein, B., & Fujita, T. (2009). Implementing China’s circular economy concept at the regional level: A review of progress in Dalian, China. Waste Management, 29(2), 996-1002.

303

Genovese, A., Acquaye, A. A., Figueroa, A., & Koh, S. L. (2017). Sustainable supply chain management and the transition towards a circular economy: Evidence and some applications. Omega, 66, 344-357. George, D. A. R., Lin, B. C. A., & Chen, Y. (2015). A circular economy model of economic growth. Environ. Model. Softw. Environmental Modelling and Software, 73, 60-63. Gerholdt, J. (2015). The Five Business Models that put the Circular Economy to work. Retrieved 04 March, 2016, from https://www.greenbiz.com/article/5-business-models- put-circular-economy-work Gertsakis, J., & Lewis, H. (2003). Sustainability and the waste management hierarchy. Retrieved 8 December 2018 from: https://www.sustainability.vic.gov.au/~/media/resources/documents/publications%20a nd%20research/publications/q%20- %20t/publications%20towards%20zero%20waste%20sustainability%20and%20the% 20waste%20hierarchy%202003.pdf Ghisellini, P., Cialani, C., & Ulgiati, S. (2016). A review on circular economy: the expected transition to a balanced interplay of environmental and economic systems. Journal of Cleaner Production 114 (2016): 11-32. Ghisellini, P., Ripa, M., & Ulgiati, S. (2018). Exploring environmental and economic costs and benefits of a circular economy approach to the construction and demolition sector. A literature review. Journal of Cleaner Production, 178, 618-643. Giacchino, S., & Kakabadse, A. (2003). Successful policy implementation: the route to building self-confident government. International Review of Administrative Sciences, 69(2), 139-160. Gihan L.G., Ahmed R. A, and Adel, E.G (2010). Material Waste in Egyptian Construction Industry. PhD Thesis at the Faculty of Engineering, University of Cairo, Egypt. Giurco, D., Littleboy, A., Boyle, T., Fyfe, J., & White, S. (2014). Circular economy: questions for responsible minerals, additive manufacturing and recycling of metals. Resources, 3(2), 432-453. Giurco, D., Cohen, B., Langham, E., & Warnken, M. (2011). Backcasting energy futures using industrial ecology. Technological Forecasting and Social Change 78(5): 797– 818. Gladek, E. (2017). The Seven Pillars of the Circular Economy. Retrieved from http://www.metabolic.nl/the-seven-pillars-of-the-circular-economy/ Glazyrina, I., Glazyrin, V., & Vinnichenko, S. (2006). The polluter pays principle and potential conflicts in society. Ecological Economics, 59(3), 324-330. Goodier, C., & Gibb, A. (2007). Future opportunities for offsite in the UK. Construction Management and Economics, 25(6), 585-595. Goulding, J. S., Pour Rahimian, F., Arif, M., & Sharp, M. D. (2015). New offsite production and business models in construction: priorities for the future research agenda. Architectural Engineering and Design Management, 11(3), 163-184. Goulding, J. S., Pour-Rahimian, F., Arif, M., & Sharp, M. D. (2012). Offsite construction: strategic priorities for shaping the future research agenda. Journal of Architectoni. ca, 1(1), 62-73. Govindan, K., & Hasanagic, M. (2018). A systematic review on drivers, barriers, and practices towards circular economy: a supply chain perspective. International Journal of Production Research, 56(1-2), 278-311. Gray, D. E. (2013). Doing research in the real world. Sage.

304

Grbich, C. (2012). Qualitative data analysis: An introduction. Sage. Green, K. & Vergragt, P. (2002). Towards sustainable households: A methodology for developing sustainable technological and social innovations. Futures 34: 381– 400. Greenwood, D., Horne, M., Thompson, E. M., Allwood, C. M., Wernemyr, C., & Westerdahl, B. (2008). Strategic perspectives on the use of virtual reality within the building industries of four countries. Architectural engineering and design management, 4(2), 85-98. Greenwood, R., Jones, P., Snow, C. and Kersey (2003). Construction Waste Minimisation: Good Practice Guide. Centre for Research in the Built Environment, Cardiff University. Gregor, L. (2014). Performance of Hempcrete Walls subjected to a standard time-temperature fire curve (Masters of Engineering Thesis, Victoria University, Melbourne, Australia). Gregory, J. (2006). Material flow analysis. Massachusetts Institute of Technology Department of Materials Science & Engineering, Cambridge, USA. Gregson, N., Crang, M., Fuller, S., & Holmes, H. (2015). Interrogating the circular economy: the moral economy of resource recovery in the EU. Economy and Society, 44(2), 218- 243. Greyson, J. (2007). An economic instrument for zero waste, economic growth and sustainability. Journal of Cleaner Production, 15(13), 1382-1390. Griffin, E. (2013). Liberty's dawn: a people's history of the Industrial Revolution. Yale University Press. Guba, E. G., & Lincoln, Y. S. (1994). Competing paradigms in qualitative research. Handbook of qualitative research, 2(163-194), 105. Guba, E. G., & Lincoln, Y. S. (2005). Paradigmatic Controversies, Contradictions, and Emerging Confluences. In N. K. Denzin & Y. S. Lincoln (Eds.), The Sage handbook of qualitative research (pp. 191-215). Thousand Oaks, CA: Sage Publications Ltd. Guerin, T. (2017). A case study identifying and mitigating the environmental and community impacts from construction of a utility-scale solar photovoltaic power plant in eastern Australia. Solar Energy, 146, 94-104. Guest, G., Bunce, A., & Johnson, L. (2006). How many interviews are enough? An experiment with data saturation and variability. Field methods, 18(1), 59-82. Guohui, S., & Yunfeng, L. (2012). The Effect of Reinforcing the Concept of Circular Economy in West China Environmental Protection and Economic Development. Procedia Environmental Sciences, 12, 785-792. Haas, W., Krausmann, F., Wiedenhofer, D., & Heinz, M. (2015). How circular is the global economy? An assessment of material flows, waste production, and recycling in the European Union and the world in 2005. Journal of Industrial Ecology, 19(5), 765-777. Hadjieva-Zaharieva, R., Dimitrova, E., & Buyle-Bodin, F. (2003). Building waste management in Bulgaria: challenges and opportunities. Waste Management, 23(8), 749-761. Hair, J. F., Black, W. C., Babin, B. J., Anderson, R. E., & Tatham, R. L. (2006). Multivariate data analysis (Vol. 6): Pearson Prentice Hall Upper Saddle River, NJ. Hair, J. F., Black, W. C., Grimm, L. G., & Yarnold, P. R. (2000). Reading and understanding more multivariate statistics. American Psychological Association, 147-205. Häkkinen, T., & Belloni, K. (2011). Barriers and drivers for sustainable building. Building Research & Information, 39(3), 239-255. Hall, J. N. (2013). Pragmatism, evidence, and mixed methods evaluation. New Directions for Evaluation, 2013(138), 15-26.

305

Hao, J. L., Hills, M. J., & Huang, T. (2007). A simulation model using system dynamic method for construction and demolition waste management in Hong Kong. Construction Innovation, 7(1), 7-21. Hao, J. L., Hills, M. J., & Tam, V. W. (2008). The effectiveness of Hong Kong's construction waste disposal charging scheme. Waste Management & Research, 26(6), 553-558. Hardie, M., Khan, M., O’Donell, S., & Miller, G. (2007). The efficacy of waste management plans in Australian commercial construction refurbishment projects. Aust. J. Constr. Econ. Build. 7, 26-36 Hardin, B. (2009). BIM and Construction Management: proven Tools, Methods, and Workflows‖ Wiley Publishing Inc. Indianapolis, Indiana. Hardison, D., Behm, M., Hallowell, M. R., & Fonooni, H. (2014). Identifying construction supervisor competencies for effective site safety. Safety science, 65, 45-53. Harper, C. M., Molenaar, K. R., & Cannon, J. P. (2016). Measuring constructs of relational contracting in construction projects: The owner’s perspective. Journal of Construction Engineering and Management, 142(10), 04016053. Harry, D. M. (2013). Research, Technology Transfer and Socio-Economic Development in Nigeria: Some Lessons from the Asian Economies. Mediterranean Journal of Social Sciences, 4(8), 119. Hassan, S. H., Ahzahar, N., Fauzi, M. A., & Eman, J. (2012). Waste management issues in the northern region of Malaysia. Procedia-Social and Behavioral Sciences, 42, 175-181. Hatcher, G. D., Ijomah, W. L., & Windmill, J. F. C. (2011). Design for remanufacture: a literature review and future research needs. Journal of Cleaner Production, 19(17-18), 2004-2014. Heck, P. (2006). Circular Economy Related International Practices and Policy Trends: Current Situation and Practices on Sustainable Production and Consumption and International Circular Economy Development Policy Summary and Analysis. Environmental Campus Birkenfeld: Institute for Applied Material Flow Management (IfaS). Hellweg, S., & i Canals, L. M. (2014). Emerging approaches, challenges and opportunities in life cycle assessment. Science, 344(6188), 1109-1113. Herremans, I., & Allwright, D. E. (2000). Environmental management systems at North American universities: what drives good performance? International Journal of Sustainability in Higher Education, 1(2), 168-181. Heshmati, A. (2015). A Review of the Circular Economy and its Implementation. IZA Discussion paper No. 9611. Available at http://ftp.iza.org/dp9611.pdf Hicks, C., & Dietmar, R. (2007). Improving cleaner production through the application of environmental management tools in China. Journal of Cleaner Production, 15(5), 395- 408. Hieminga, G. (2015). Rethinking Finance in a Circular Economy: Financial Implications of Circular Business Models (E. Department, Trans.). The Netherlands: ING Bank. Hislop, H., & Hill, J. (2011). Reinventing the wheel: a circular economy for resource security. Green Alliance. HKICM (2018). HKIPM and HKICM Joint CPD Seminar on Smart Waste Management: Mainland China Experience. Retrieved 10 February 2019 from http://www.hkicm.org.hk/cpd197.html HM Government (2008). The site waste management plans regulations 2008. Statutory Instrument 2008 No. 314. London: The Stationery Office.

306

Ho, P. H. (2016). Labour and skill shortages in Hong Kong’s construction industry. Engineering, Construction and Architectural Management, 23(4), 533-550. Hobday, M. (2000). The project-based organisation: an ideal form for managing complex products and systems? Research policy, 29(7), 871-893. Hogg, M., & Vaughan, G. (2005). Social Psychology (4th edition). London: Prentice-Hall. Holmes, A. (2013). Direct observation. Encyclopedia of autism spectrum disorders, 980-981. Hong, X. (2002). A comparative study of contractor performance based on Japanese, UK and US construction practice. University of Wolverhampton. Howell, I., & Batcheler, B. (2010). Building Information Modeling two years later – huge potentials, some success and several limitations. Newforma. International Alliance for Interoperability. Huamao, X., & Fengqi, W. (2007). Circular economy development mode based on system theory. Chinese Journal of Population Resources and Environment, 5(4), 92-96. Huang, B., Wang, X., Kua, H., Geng, Y., Bleischwitz, R., & Ren, J. (2018). Construction and demolition waste management in China through the 3R principle. Resources, Conservation and Recycling, 129, 36-44. Huang, C. (2012). Developing circular economy capability: antecedents, mechanisms, and outcomes in Chinese manufacturing industry. University of Toledo. Huang, S. L., & Hsu, W. L. (2003). Materials flow analysis and emergy evaluation of Taipei’s urban construction. Landscape and Urban Planning, 63(2), 61-74. Hunter, N. (2013). Designing for a Circular Economy. Retrieved 04 March, 2016, from https://www.accenture.com/us-en/insight-circular-advantage-innovative-business- models-value-growth.aspx Hwang, B. G., & Bao Yeo, Z. (2011). Perception on benefits of construction waste management in the Singapore construction industry. Engineering, Construction and Architectural Management, 18(4), 394-406. Hwang, B. G., & Ng, W. J. (2013). Project management knowledge and skills for green construction: Overcoming challenges. International Journal of Project Management, 31(2), 272-284. Idehen, M. (2008, April 26). Infrastructure is the biggest challenge to business in Nigeria. The Punch Newspaper. Retrieved from https://punchng.com/infrastructure-deficit- challenge-growing-nigerian-economy-1/ Idoro, G. I. (2009). Clients' perception of construction project leaders in the Nigerian banking industry. Journal of Engineering, Design and Technology, 7(3), 264-281. Idoro, G. I. (2012). Comparing the planning and performance of direct labour and design-bid- build construction projects in Nigeria. Journal of Civil Engineering and Management, 18(2), 184-196. Ijaiya, H., & Joseph, O. T. (2014). Rethinking environmental law enforcement in Nigeria. Beijing L. Rev., 5, 306. Ikau, R., Joseph, C., & Tawie, R. (2016). Factors influencing waste generation in the construction industry in Malaysia. Procedia-Social and Behavioral Sciences, 234, 11- 18. IMSA. (2013). Unleashing the power of the circular economy. Retrieved May 1, 2016, from https://www.viawater.nl/files/unleashing_the_power_of_the_circular_economy- circle_economy.pdf

307

Innes, S. (2004). Developing tools for designing out waste pre-site and on-site. In Proceedings of Minimising Construction Waste Conference: Developing Resource Efficiency and Waste Minimisation in Design and Construction. New Civil Engineer London, UK. International Standard Organisation (ISO) (2006). ISO 15686-5: 2006 Building and constructed assets - Service life planning: Part 5 -Whole-life costing. In: ISO (ed.) Draft ed. Geneva. Irurah, D. K. (2001). Agenda for Sustainable Construction in Africa. An Invited Contribution to CIB’s Agenda for Sustainable Construction in the Developing World and Agenda 21 on Sustainable Construction. Isa, R. B., Jimoh, R. A., & Achuenu, E. (2013). An overview of the contribution of construction sector to sustainable development in Nigeria. Net Journal of Business Management, 1(1), 1-6. Iung, B., & Levrat, E. (2014). Advanced maintenance services for promoting sustainability. Procedia CIRP, 22, 15-22. Jackson, M., Lederwasch, A., & Giurco, D. (2014). Transitions in Theory and Practice: Managing Metals in the Circular Economy. Resources, 3(3), 516-543. Jackson, T. (2007). 16 Sustainable consumption. Handbook of sustainable development, 254. Jackson, T., & Michaelis, L. (2003). Policies for sustainable consumption. Sustainable Development Commission, London. Jailani, J., Reed, R., & James, K. (2015). Examining the perception of tenants in sustainable office buildings. Property Management, 33(4), 386-404. Jaillon, L., & Poon, C. S. (2009). The evolution of prefabricated residential building systems in Hong Kong: A review of the public and the private sector. Automation in construction, 18(3), 239-248. Jaillon, L., Poon, C. S., & Chiang, Y. H. (2009). Quantifying the waste reduction potential of using prefabrication in building construction in Hong Kong. Waste management, 29(1), 309-320. Jain, M. (2012). Economic Aspects of Construction Waste Materials in terms of cost savings– A case of Indian construction Industry. International Journal of Scientific and Research Publications, 2(10), 1-7. Jalali, S. (2007). Quantification of construction waste amount. Prepared for Handbook of Wastetool. James, K. (2011). A Methodology for Quantifying the Environmental and Economic Impacts of Reuse. United Kingdom: Waste and Resources Action Programme. Jawahir, I. S., & Bradley, R. (2016). Technological elements of circular economy and the principles of 6R-based closed-loop material flow in sustainable manufacturing. Procedia Cirp, 40, 103-108. Ji, X., Zhang, Y., & Hao, L. (2012). Analyses of Japanese Circular Economy Mode and its Inspiration Significance for China. Journal of Advances in Asian Social Science (AASS), 3(4), 725-730. Jingkuang, L., & Yousong, W. (2011). Establishment and application of performance assessment model of waste management in architectural engineering projects in China. Systems Engineering Procedia, 1, 147-155. Johansson, C., Elfsberg, J., Larsson, T. C., Frank, M., Leifer, L. J., Nilsson, N., & Söderberg, V. (2016). Urban Mining as a Case for PSS. Procedia CIRP, 47, 460-465.

308

John, V. M., Angulo, S. C., Miranda, L. F., Agopyan, V., & Vasconcellos, F. (2004). Strategies for innovation in construction and demolition waste management in Brazil. In Toronto: CIB World Building Congress, National Research Council of Canada. Johnson, R. B., & Onwuegbuzie, A. J. (2004). Mixed methods research: A research paradigm whose time has come. Educational researcher, 33(7), 14-26. Jones, P., & Comfort, D. (2018). The construction industry and the circular economy. International Journal of Management Cases, 20(1), 4-15. Jones, P., & Greenwood, R. (2003). Construction waste minimisation from the UK housing sector. Centre for Research on the Built Environment, Welsh School of Architecture. Cardiff University, Cardiff. JRC (Joint Research Center) (2008). Backcasting approach for sustainable mobility. Ispra, Italy: Joint Research Center (JRC). Jun, H., & Xiang, H. (2011). Development of Circular Economy Is A Fundamental Way to Achieve Agriculture Sustainable Development in China. Energy Procedia, 5, 1530- 1534. doi: http://dx.doi.org/10.1016/j.egypro.2011.03.262 Kai, M. (2004). Implementation of Scientific Development Outlook and Promotion of Circular Economy in China. Paper presented at the National Economy Conference, China. Kaiser, H. F. (1974). An index of factorial simplicity. Psychometrika, 39(1), 31-36. Kale, S., & Arditi, D. (2005). Diffusion of computer aided design technology in architectural design practice. Journal of Construction Engineering and Management, 131(10), 1135-1141. Kale, S., & Arditi, D. (2006). Diffusion of ISO 9000 certification in the precast concrete industry. Construction Management and Economics, 24(5), 485-495. Kale, S., & Arditi, D. (2010). Innovation diffusion modeling in the construction industry. Journal of Construction Engineering and Management, 136(3), 329-340. Kalmykova, Y., Sadagopan, M., & Rosado, L. (2018). Circular economy–From review of theories and practices to development of implementation tools. Resources, Conservation and Recycling, 135, 190-201. Kalof, L., Dan, A., & Dietz, T. (2008). Essentials of social research. McGraw-Hill Education (UK). Kane, G. M., Bakker, C. A., & Balkenende, A. R. (2018). Towards design strategies for circular medical products. Resources, Conservation and Recycling, 135, 38-47. Kankara, A. I., Adamu, G. K., Tukur, R., & Ibrahim, A. (2013). Examining environmental policies and laws in Nigeria. Int J Environ Eng Manag, 4, 165-170. Kareem, W. A., Asa, O. A., & Lawal, M. O. (2015). Resources conservation and waste management practices in construction industry. Oman Chapter of Arabian Journal of Business and Management Review, 34(2603), 1-12. Karlsson, R., & Luttropp, C. (2006). EcoDesign: what's happening? An overview of the subject area of EcoDesign and of the papers in this special issue. Journal of cleaner production, 14(15-16), 1291-1298. Kartam, N., Al-Mutairi, N., Al-Ghusain, I., & Al-Humoud, J. (2004). Environmental management of construction and demolition waste in Kuwait. Waste management, 24(10), 1049-1059. Katz, A., & Baum, H. (2011). A novel methodology to estimate the evolution of construction waste in construction sites. Waste management, 31(2), 353-358.

309

Kemp, R., & Martens, P. (2007). Sustainable development: how to manage something that is subjective and never can be achieved. Sustainability: Science, Practice, & Policy, 3(2), 5-14. Kennedy, C., Cuddihy, J., & Engel‐Yan, J. (2007). The changing metabolism of cities. Journal of industrial ecology, 11(2), 43-59. Khoo, J. (2015). Service design. I don't need a drill I need a hole. The circular economy in organisations—University College London, London, 11. Kibert, C. J. (1994). Establishing principles and a model for sustainable construction. In Proceedings of the first international conference on sustainable construction (pp. 6- 9). Tampa Florida, November. Kibert, C. J. (2012). Closing materials loop. Sustainable Construction: Green Building Design and Delivery, 3. Kim, H., & Grobler, F. (2009). Design coordination in building information modeling (BIM) using ontological consistency checking. In Computing in Civil Engineering (2009) (pp. 410-420). King, G., Keohane, R. O., & Verba, S. (1994). Designing social inquiry: Scientific inference in qualitative research. Princeton university press. Kirchherr, J., Reike, D., & Hekkert, M. (2017). Conceptualizing the circular economy: An analysis of 114 definitions. Resources, Conservation and Recycling, 127, 221-232. Knapp, K. J., & Ferrante, C. J. (2012). Policy awareness, enforcement and maintenance: Critical to information security effectiveness in organizations. Journal of Management Policy and Practice, 13(5), 66-80. Knight, P., & Jenkins, J. O. (2009). Adopting and applying eco-design techniques: a practitioner’s perspective. Journal of cleaner production, 17(5), 549-558. Kofoworola, O. F., & Gheewala, S. H. (2009). Estimation of construction waste generation and management in Thailand. Waste management, 29(2), 731-738. Kohler, N., & Yang, W. (2007). Long-term management of building stocks. Building Research & Information 35(4), 351-362. Kolo, D. N. (2015). Safety Issues involving workers on building construction sites in Nigeria: An Abuja Study (Doctoral dissertation, Eastern Mediterranean University (EMU)-Doğu Akdeniz Üniversitesi (DAÜ)). Korhonen, J., Honkasalo, A., & Seppälä, J. (2018). Circular economy: the concept and its limitations. Ecological economics, 143, 37-46. Korhonen, J., Nuur, C., Feldmann, A., & Birkie, S. E. (2018). Circular economy as an essentially contested concept. Journal of Cleaner Production, 175, 544-552. Koskela, L. (1992). Application of the new production philosophy to construction (Vol. 72). Stanford: Stanford University. Koutsogiannis, A. (2018) Modern methods of construction: The future is now! Retrieved 20 January 2019 from https://geniebelt.com/blog/modern-methods-of-construction Kruskal, W. H., & Wallis, W. A. (1952). Use of ranks in one-criterion variance analysis. Journal of the American statistical Association, 47(260), 583-621. Krygiel, E., & Nies, B. (2008). Green BIM: successful sustainable design with building information modeling. John Wiley & Sons. Kulatunga, U., Amaratunga, D., Haigh, R., & Rameezdeen, R. (2006). Attitudes and perceptions of construction workforce on construction waste in Sri Lanka. Management of Environmental Quality: An International Journal, 17(1), 57-72.

310

Kumar, R. (2011). Research Methodology: A Step by Step Guide for Beginners (3rd ed.). London: Sage Publications Limited. Kumaraswamy, M. M., Ng, S. T., Palaneeswaran, E., Rahman, M. M., Ugwu, O. O., & Sze, E. K. K. (2004). Top-down and bottom-up construction industry development. Globalisation and Construction, 497. Kuroshi, P. A., & Lawal, M. (2014). Study of internal factors affecting labour productivity in medium sized construction firms in Nigeria. International Journal of Education and Research, 2(12), 83-92. La Clara, B., & Gemke, S. (2013). A Summary about the Interview as Research Method. PhD Seminar. Swiss Federal Institute of Technology, Zurich. Lacy, P., & Rutqvist, J. (2015). The Product as a Service Business Model: Performance over Ownership. In Waste to Wealth (pp. 99-114). Palgrave Macmillan, London. Lacy, P., & Rutqvist, J. (2016). Waste to wealth: The circular economy advantage. Springer. Lacy, P., Rosenberg, D., Drewell, Q., & Rutgvist, J. (2013). 5 Business Models that are driving the Circular Economy. Retrieved 04 March, 2016, from http://www.fastcoexist.com/1681904/5-business-models-that-are-driving-the-circular- economy Ladan, M. T. (2012). Review of NESREA act 2007 and regulations 2009-2011: a new Dawn in environmental compliance and enforcement in Nigeria. Law Env't & Dev. J., 8, 116. Ladan, M. T. (2016). Sanitation and Waste Management-Part 1: Overview. Environmental Policy and Law, 46(2), 175. Lafarge Holcim Foundation (2015). Understanding Sustainable Construction. Retrieved from https://www.lafargeholcim-foundation.org/about/sustainable-construction Lagos State Government (2017). Lagos State Physical Planning Permit Authority. Retrieved from https://laspppa.lagosstate.gov.ng/ Lagos. (n.d.). In Wikipedia. Retrieved June 15 2018 from https://en.wikipedia.org/wiki/Lagos#/media/File:Map_of_the_Local_Government_Ar eas_of_Lagos.png Lam, A.L.P. (1997). A Study of the Development of Environmental Management in Hong Kong Construction Industry, BSc Thesis, the Hong Kong Polytechnic University. Langdon, D. (2007). Life Cycle Costing (LCC) as a contribution to sustainable construction: a common methodology. Literature Review, Davis Langdon Management Consulting. Larsen, G. D., & Ballal, T. M. (2005). The diffusion of innovations within a UKCI context: an explanatory framework. Construction Management and Economics, 23(1), 81-91. Lau, H. H., Whyte, A., & Law, P. L. (2008). Composition and Characteristics of Construction Waste Generated by Residential Housing Project. International Journal of Environmental Research, 2(3). Lawson, M., Ogden, R., & Goodier, C. (2014). Design in modular construction. CRC Press. Lawton, T., Rajwani, T., & Doh, J. (2013). The antecedents of political capabilities: A study of ownership, cross-border activity and organization at legacy airlines in a deregulatory context. International Business Review, 22(1), 228-242. Lazarevic, D., Buclet, N., & Brandt, N. (2012). The application of life cycle thinking in the context of European waste policy. Journal of Cleaner Production, 29, 199-207. Lee, Y. J., & Greene, J. (2007). The predictive validity of an ESL placement test: A mixed methods approach. Journal of Mixed Methods Research, 1(4), 366-389.

311

Lehtoranta, S., Nissinen, A., Mattila, T., & Melanen, M. (2011). Industrial symbiosis and the policy instruments of sustainable consumption and production. Journal of Cleaner Production, 19(16), 1865-1875. Leiserowitz, A. A., Kates, R. W., & Parris, T. M. (2006). Sustainability values, attitudes, and behaviors: A review of multinational and global trends. Annu. Rev. Environ. Resour., 31, 413-444. Lenzen, M., Murray, J., Sack, F., & Wiedmann, T. (2007). Shared producer and consumer responsibility—Theory and practice. Ecological economics, 61(1), 27-42. Leslie, H. A., Leonards, P. E. G., Brandsma, S. H., De Boer, J., & Jonkers, N. (2016). Propelling plastics into the circular economy—weeding out the toxics first. Environment international, 94, 230-234. Lett, L. A. (2014). Global threats, waste recycling and the circular economy concept. Lewandowski, M. (2016). Designing the business models for circular economy—Towards the conceptual framework. Sustainability, 8(1), 43. Lewis, J., & Ritchie, J. (2003). Generalising from qualitative research. Qualitative research practice: A guide for social science students and researchers, 2, 347-362. Li, B., & Li, M. (2008). Study on the Sustainable Development Ability Assessment of Green Supply Chain Based on Circular Economy. Logistics Research and Practice in China, 502-508. Li, D.H., & Duan, Z.Z. (2006). Disposal of the construction waste and recycling economy. Opt. Capital Constr., 27, 41-45. Li, H., & Chai, L. (2007). Thermodynamic analyses on technical framework of clean production. Journal of Cleaner Production, 15(4), 357-365. doi: http://dx.doi.org/10.1016/j.jclepro.2005.08.002 Li, J., Tam, V. W., Zuo, J., & Zhu, J. (2015). Designers’ attitude and behaviour towards construction waste minimization by design: A study in Shenzhen, China. Resources, Conservation and Recycling, 105, 29-35. Li, S. (2012). The Research on Quantitative Evaluation of Circular Economy Based on Waste Input-Output Analysis. Procedia Environmental Sciences, 12, Part A, 65-71. doi: http://dx.doi.org/10.1016/j.proenv.2012.01.248 Liang, H. H., & Ho, M. C. (2007). Toxicity characteristics of commercially manufactured insulation materials for building applications in Taiwan. Construction and Building Materials, 21(6), 1254-1261. Lieder, M., & Rashid, A. (2016). Towards circular economy implementation: a comprehensive review in context of manufacturing industry. Journal of cleaner production, 115, 36- 51. Lifset, R., & Graedel, T. E. (2002). Industrial ecology: goals and definitions. A handbook of industrial ecology, 3-15. Lim, C., & Mohamed, M. Z. (1999). Criteria of project success: an exploratory re-examination. International journal of project management, 17(4), 243-248. Lincoln, Y. S., Lynham, S. A., & Guba, E. G. (2011). Paradigmatic controversies, contradictions, and emerging confluences, revisited. The Sage handbook of qualitative research, 4, 97-128. Lingard, H., Graham, P., & Smithers, G. (2000). Employee perceptions of the solid waste management system operating in a large Australian contracting organization:

312

implications for company policy implementation. Construction Management & Economics, 18(4), 383-393. Liu, J. Y. S. (2012). Circular economy and environmental efficiency–the case of traditional Hakka Living system. Procedia-Social and Behavioural Sciences, 57, 255-260. Liu, J., & Wang, Y. (2013). Cost analysis of construction and demolition waste management: Case study of the Pearl River delta of China. The Open Construction and Building Technology Journal, 7(1). Liu, L., Liang, Y., Song, Q., & Li, J. (2017). A review of waste prevention through 3R under the concept of circular economy in China. Journal of Material Cycles and Waste Management, 19(4), 1314-1323. Liu, Q., Li, H.-m., Zuo, X.-l., Zhang, F.-f., & Wang, L. (2009). A survey and analysis on public awareness and performance for promoting circular economy in China: A case study from Tianjin. Journal of Cleaner Production, 17(2), 265-270. doi: http://dx.doi.org/10.1016/j.jclepro.2008.06.003 Liu, Z., Osmani, M., Demian, P., & Baldwin, A. (2015). A BIM-aided construction waste minimisation framework. Automation in construction, 59, 1-23. Löfgren, J., & Enocson, H. (2014). Textile and recycling initiatives–A step towards a circular economy. Long, C. S., Ajagbe, M. A., Khalil, N. M., & Suleiman, E. S. (2012). The Approaches to Increase Employees’ Loyalty: A Review on Employees’ Turnover Models. Australian Journal of Basic and Applied Sciences, 6(10): 282-291. Lowe, D. G. (2001). Local feature view clustering for 3D object recognition. Paper presented at the Computer Vision and Pattern Recognition, 2001. CVPR 2001. Proceedings of the 2001 IEEE Computer Society Conference. Lu, W. & Yuan, H. (2010). Exploring critical success factors for waste management in construction projects of China. Resources, conservation and recycling, 55(2), pp., 201- 208. Lu, W., & Tam, V. W. (2013). Construction waste management policies and their effectiveness in Hong Kong: A longitudinal review. Renewable and sustainable energy reviews, 23, 214-223. Lu, W., & Yuan, H. (2013). Investigating waste reduction potential in the upstream processes of offshore prefabrication construction. Renewable and Sustainable Energy Reviews, 28, 804-811. Lu, W., Shen, L., & Yam, M. C. (2008). Critical success factors for competitiveness of contractors: China study. Journal of construction engineering and management, 134(12), 972-982. Lu, W., Yuan, H., Li, J., Hao, J. J., Mi, X., & Ding, Z. (2011). An empirical investigation of construction and demolition waste generation rates in Shenzhen city, South China. Waste management, 31(4), 680-687. Luttropp, C., & Lagerstedt, J. (2006). EcoDesign and The Ten Golden Rules: generic advice for merging environmental aspects into product development. Journal of Cleaner Production, 14(15-16), 1396-1408. Ma, J. J., Liu, L. Q., Su, B., & Xie, B. C. (2015). Exploring the critical factors and appropriate polices for reducing energy consumption of China's urban civil building sector. Journal of Cleaner Production, 103, 446-454.

313

Ma, S. H., Wen, Z. G., Chen, J. N., & Wen, Z. C. (2014). Mode of circular economy in China's iron and steel industry: a case study in Wu'an city. Journal of Cleaner Production, 64, 505-512. Mackenzie, N., & Knipe, S. (2006). Research dilemmas: Paradigms, methods and methodology. Issues in educational research, 16(2), 193-205. Malterud, K., Siersma, V. D., & Guassora, A. D. (2016). Sample size in qualitative interview studies: guided by information power. Qualitative health research, 26(13), 1753-1760. Mansfield, N. R., Ugwu, O., & Doran, T. (1994). Causes of delay and cost overruns in Nigerian construction projects. International journal of project management, 12(4), 254-260. Mansikkasalo, A., Lundmark, R., & Söderholm, P. (2014). Market behavior and policy in the recycled paper industry: A critical survey of price elasticity research. Forest Policy and Economics, 38, 17-29. Mantoux, P. (2013). The industrial revolution in the eighteenth century: An outline of the beginnings of the modern factory system in England. Routledge. Masi, D., Day, S., & Godsell, J. (2017). Supply chain configurations in the circular economy: A systematic literature review. Sustainability, 9(9), 1602. Mat, M. M. C. (2002). Value Management: Principle and Applications; Towards Achieving Better Value for Your Money. Prentice Hall/Kreatif Kembara. Mata, R., Pitroda, J., & Vyas, C.M. (2015). A Critical Literature Review on Integrated Framework for Source Identification and Minimization of Waste in Building Construction. Journal of International Academic Research for Multidisciplinary, 2(12), 163 – 175. Mata, T.M., Mendes, A.M., Caetano, N.S. and Martins, A.A. (2014). Sustainability and economic evaluation of microalgae grown in brewery wastewater. Bioresource technology, 168, pp.151-158. Matar, M. M., Georgy, M. E., & Ibrahim, M. E. (2008). Sustainable construction management: introduction of the operational context space (OCS). Construction Management and Economics, 26(3), 261-275. Mathews, J. A., & Tan, H. (2011). Progress toward a Circular Economy in China. Journal of Industrial Ecology, 15(3). Matofska, B. (2016). What is the Sharing Economy? Retrieved from http://www.thepeoplewhoshare.com/blog/what-is-the-sharing-economy/ Matthews, B., & Ross, L. (2014). Research methods. Pearson Higher Ed. Mattiussi, A., Rosano, M., & Simeoni, P. (2014). A decision support system for sustainable energy supply combining multi-objective and multi-attribute analysis: An Australian case study. Decision Support Systems, 57, 150-159. Matus, K. J., Xiao, X., & Zimmerman, J. B. (2012). Green chemistry and green engineering in China: drivers, policies and barriers to innovation. Journal of Cleaner Production, 32, 193-203. Mbamali, I., & Okotie, A. (2012). An assessment of the threats and opportunities of globalization on building practice in Nigeria. Mcdonald, B., & Smithers, M. (1998). Implementing a waste management plan during the construction phase of a project: a case study. Construction Management & Economics, 16(1), 71-78. McDonough, W., & Braungart, M. (2002). Cradle to Cradle: Rethinking the way we make things. North Point, NY.

314

McDonough, W., & Braungart, M. (2010). Cradle to cradle: Remaking the way we make things: MacMillan. McDonough, W., & Braungart, M. (2013). The upcycle: Beyond sustainability--designing for abundance. Macmillan. McDonough, W., Braungart, M., Anastas, P. T., & Zimmerman, J. B. (2003). Applying the principles of green engineering to cradle-to-cradle design. Environmental science & technology, 37(23), 434A-441A. McIntosh, A., & Pontius, J. (2016). Science and the global environment: case studies for integrating science and the global environment. Elsevier. McKinsey & Company (2015, September). Europe's circular economy opportunity. Retrieved from http://www.mckinsey.com/business‐functions/sustainability‐and‐resource‐ productivity/our‐insights/europes‐circular‐economy‐opportunity McLeod, S. (2018). Attitudes and Behaviour. Retrieved 18 February, 2019 from: https://www.simplypsychology.org/attitudes.html Medugu, N. I., Majid, M. R., Bustani, S. A., Bala, K., Abdullahi, U., & Mbamali, I. (2011). Craft Skills Availability in the Nigerian Construction Industry: Perception of Contractors and Consultants. IUP Journal of Infrastructure, 9(3). Mefteh, H., Kebaïli, O., Oucief, H., Berredjem, L., & Arabi, N. (2013). Influence of moisture conditioning of recycled aggregates on the properties of fresh and hardened concrete. Journal of cleaner production, 54, 282-288. Mendoza, J. M. F., Sharmina, M., Gallego‐Schmid, A., Heyes, G., & Azapagic, A. (2017). Integrating Backcasting and Eco‐Design for the Circular Economy: The BECE Framework. Journal of Industrial Ecology, 21(3), 526-544. Menikpura, S., Gheewala, S. H., Bonnet, S., & Chiemchaisri, C. (2013). Evaluation of the effect of recycling on sustainability of municipal solid waste management in Thailand. Waste and Biomass Valorization, 4(2), 237-257. Meqdadi, O., Johnsen, T., & Joh, R. (2012). The Role of SME Suppliers in Implementing Sustainability. Piccola Impresa/Small Business (2). Merrian-Webster Dictionary, O. (Ed.) (2016) Online Dictionary. Merriam Webster. Mesthrige Jayantha, W., & Sze Man, W. (2013). Effect of green labelling on residential property price: a case study in Hong Kong. Journal of Facilities Management, 11(1), 31-51. Miller, S. (2006). Mixed methods as methodological innovations: Problems and prospects. Methodological Innovations Online, 1(1), 29-33. Mills, T.M., Showalter, E. and Jarman, D. (1999). A cost-effective waste management plan, Cost Engineering, 41(3), 35-43. Minunno, R., O’Grady, T., Morrison, G., Gruner, R., & Colling, M. (2018). Strategies for Applying the Circular Economy to Prefabricated Buildings. Buildings, 8(9), 125. Momoh, S. (2011, 03 October 2011). Why SMEs Should Explore Nigerian Oil and Gas Sector. Business Day. Retrieved from http://businessdayonline.com/2011/10/why-smes- should-explore-nigerian-oil-and-gas-sector/ Moon, D. & Holton, I. (2011). Learning legacy, Lessons learned from the London 2012 Games construction project. Retrieved from https://tinyurl.com/hn3loo7 Moreau, V., Sahakian, M., Van Griethuysen, P., & Vuille, F. (2017). Coming full circle: why social and institutional dimensions matter for the circular economy. Journal of Industrial Ecology, 21(3), 497-506.

315

Moreno, M., Braithwaite, N., & Cooper, T., (2015). Moving beyond the circular economy. Proceedings of Going Green-CARE Innovation, 1-10. Morgan, D. L. (2014). Pragmatism as a paradigm for social research. Qualitative Inquiry, 20(8), 1045-1053. Morse, J. M. (2015). “Data Were Saturated . . . .” Qualitative Health Research, 25(5), 587– 588. https://doi.org/10.1177/1049732315576699 Moscarola, J. (2002). Contribution of qualitative methods to research in work and organizational psychology. Sphinx lexica and MCA. Communication to ISSWOV. Mudashiru, R. B., Oyelakin, M. A., Oyeleke, M. O., & Bakare, S. B. (2016). Reuse of Construction and Demolition Waste in Edun, Ilorin, North Central Nigeria. Technology (ICONSEET), 1(12), 85-89. Muhwezi, L., Chamuriho, L. M., & Lema, N. M. (2012). An investigation into materials wastes on building construction projects in Kampala-Uganda. Scholarly Journal of Engineering Research 1(1): 11-18. Mulder, I. (2012). Living labbing the Rotterdam way: Co-creation as an enabler for urban innovation. Technology Innovation Management Review, 2(9): 39–43. http://timreview.ca/article/607 Muralikrishna, I. V., & Manickam, V. (2017). Chapter five-life cycle assessment. In Environmental Management (pp. 57-75). Butterworth-Heinemann. Murray, A., Skene, K., & Haynes, K. (2017). The Circular Economy: An Interdisciplinary Exploration of the Concept and Application in a Global Context. Journal of Business Ethics, 140(3), 369-380. Murray, P. E., & Cotgrave, A. J. (2007). Sustainability literacy: the future paradigm for construction education? Structural Survey, 25(1), 7-23. Nadim, W. & Goulding, J.S. (2010). Offsite Production: A Model for Building Down Barriers: A European Construction Industry Perspective. Journal of Engineering, Construction and Architectural Management, 18(1): p. 82-101 Nagapan, S., Ismail, A. R., & Ade, A. (2011). A review of construction waste cause factors. In Proceedings of the Asian Conference of Real Estate: Sustainable Growth Managing Challenges (ACRE), Johor, Malaysia. Nagapan, S., Rahman, I.A. and Asmi, A. (2012). Factors contributing to physical and non- physical waste generation in construction industry. International Journal of Advances in Applied Sciences, 1(1), pp.1-10. Nagaraju, S.K., Reddy, B.S., & Chaudhuri, A.R. (2012). Resource Management in Construction Projects – A case study. Engineering Science and Technology: An International Journal, 2(4): 660-665. Napier, T. (2012). Construction waste management. National Institute of Building Science. Retrieved 11 January 2019 from: http://www.wbdg.org/resources/cwmgmt.php National Bureau of Statistics (2018). GDP Report for Second Quarter, 2018. Building & Construction, 2018. Retrieved December 4 2018 from www.nigeriastat.gov.ng National Bureau of Statistics, N. (2015). Nigerian Construction Sector, Summary Report: 2010 - 2012. Nigeria. Available at: http://www.nigerianstat.gov.ng/ National Bureau of Statistics, N. (2017). Contributions to real GDP in 2017. Available at: http://www.nigerianstat.gov.ng/

316

National Environment Standards and Regulations Enforcement Agency (NESREA) (2007). A Synopsis of Law and Regulation on the Environment in Nigeria. A Publication of the National Environmental Standards and Regulations Enforcement Agency. National Environment Standards and Regulations Enforcement Agency (NESREA) (2010). The National Environmental (Construction sector) Regulations 2010. S.I. No 19. Retrieved from http://www.nesrea.gov.ng/publications-downloads/laws-regulations/ National Environment Standards and Regulations Enforcement Agency (NESREA) (2018). Our Functions. Retrieved from http://www.nesrea.gov.ng/our-functions/ National Institute of Building Sciences (NIBS) (2007). United States National Building Information Modeling Standard. Version 1 - Part 1: Overview, principles, and methodologies. NIBS. National Planning Commission (2009). Nigeria Vision 20: 2020: Economic Transformation Blue Print, Abuja: National Planning Commission. Naustdalslid, J. (2014). Circular economy in China–the environmental dimension of the harmonious society. International Journal of Sustainable Development & World Ecology, 21(4), 303-313. Negny, S., Belaud, J. P., Robles, G. C., Reyes, E. R., & Ferrer, J. B. (2012). Toward an eco- innovative method based on a better use of resources: application to chemical process preliminary design. Journal of Cleaner Production, 32, 101-113. Nelson, J. (2017). Using conceptual depth criteria: addressing the challenge of reaching saturation in qualitative research. Qualitative research, 17(5), 554-570. Ness, D. (2008). Sustainable urban infrastructure in China: Towards a Factor 10 improvement in resource productivity through integrated infrastructure systems. The International Journal of Sustainable Development & World Ecology, 15(4), 288-301. Ness, D., & Atkinson, B. (2001). Re-use/upgrading of existing building stock. BDP Environment Design Guide. Ness, K. (2010). The discourse of ‘Respect for People’ in UK construction. Construction management and economics, 28(5), 481-493. Neuman, M., & Churchill, S. W. (2011). A general process model of sustainability. Industrial & Engineering Chemistry Research, 50(15), 8901-8904. Newport, D., Chesnes, T., & Lindner, A. (2003). The “environmental sustainability” problem: ensuring that sustainability stands on three legs. International Journal of Sustainability in Higher Education, 4(4), 357-363. Newzoo (2018). Top 100 Countries/Markets by Smartphone users and penetration. Retrieved 14 December 2018 from https://newzoo.com/insights/rankings/top-50-countries-by- smartphone-penetration-and-users/ Nexus Commonwealth Network (2019). Nigeria: Government Ministries. Retrieved 9 February 2019 from http://www.commonwealthofnations.org/sectors- nigeria/government/government_ministries/ Ng, W. Y., & Chau, C. K. (2015). New life of the building materials-recycle, reuse and recovery. Energy procedia, 75, 2884-2891. Ngacho, C., & Das, D. (2014). A performance evaluation framework of development projects: An empirical study of Constituency Development Fund (CDF) construction projects in Kenya. International Journal of Project Management, 32(3), 492-507. Nicholls, D. (2009a). Qualitative research: part one–philosophies. International Journal of Therapy and Rehabilitation, 16(10), 526-533.

317

Nicholls, D. (2009b). Qualitative research: Part three--Methods. International Journal of Therapy & Rehabilitation, 16(12). Niero, M., Hauschild, M. Z., Hoffmeyer, S. B., & Olsen, S. I. (2017). Combining eco‐efficiency and eco‐effectiveness for continuous loop beverage packaging systems: Lessons from the Carlsberg circular community. Journal of Industrial Ecology, 21(3), 742-753. Nigeria Extractive Industries Transparency Initiatives (NEITI) Act, (2007). Federal Republic of Nigeria. Retrieved 11 February 2019 from http://www.neiti.org.ng Nilsson, L. (2007). Cleaner Production: Technologies and Tools for Resource Efficient Production (Vol. 2). Baltic University Press. NIOB (2005). Facilities management for sustainable building performance. A Technical Paper at the 2-days National Seminar organized by the Nigerian Institute of Building (NIOB) at Lafia, Nasarawa State. Nnadi, E. O. E., & Ugwu, O. O. (2014). Managing Construction Risk in Nigeria through Capitalization of Construction Firms. In Int'l Conference on Artificial Intelligence, Energy and Manufacturing Engineering (ICAEME’2014) (pp. 9-10). NSW EPA (2016) Waste Less, Recycle More: A $337 million grants and funding initiative 2017-2021 extension. Retrieved 20 January 2019 from https://www.epa.nsw.gov.au/- /media/epa/corporate-site/resources/waste/waste-less-recycle-more-2017-21- brochure- 160538.pdf?la=en&hash=7C6B86664897EBE5ECA8702C6E0BD3D6D976DA0E Nuñez-Cacho, P., Górecki, J., Molina-Moreno, V., & Corpas-Iglesias, F. (2018). What gets measured, gets done: Development of a circular economy measurement scale for building industry. Sustainability, 10(7), 2340. Nurul Diyana, A., & Abidin, N. Z. (2013). Motivation and expectation of developers on green construction: a conceptual view. In Proceedings of World Academy of Science, Engineering and Technology, 76, 247. Nwokoro, I., & Onukwube, H. (2011). “Sustainable” or “green” construction in Lagos, Nigeria: principles, attributes and framework. In West Africa Built Environment Research (WABER) Conference 19-21 July 2011 Accra, Ghana (p. 883). Nwokoro, I., & Onukwube, H. (2015). Understanding green and sustainable construction in Lagos, Nigeria: Principles, attributes and framework. Ethiopian Journal of Environmental Studies and Management, 8(1), 57–68. O’Hare, J. A. (2010). Eco-innovation tools for the early stages: An industry-based investigation of tool customisation and introduction. Ph.D. thesis, Department of Mechanical Engineering, University of Bath. O’Neill, B. (2010). Behaviour Change Generally a Gradual Process. Retrieved 13 July 2017 from: https://njaes.rutgers.edu/sshw/message/message.php?p=Finance&m=165 O’Reilly, A. (2012). Using BIM as a tool for cutting construction waste at source. Construction Research and Innovation, 3(1), 28-31. O’reilly, M., & Parker, N. (2013). ‘Unsatisfactory Saturation’: a critical exploration of the notion of saturated sample sizes in qualitative research. Qualitative research, 13(2), 190-197. O’Rourke, L. (2016). DFMA in Housing. Retrieved 20 October 2018 from http://www.laingorourke.com/media/eej-2016/dfma-in-housing.aspx

318

Odediran, S. J., Adeyinka, B. F., Opatunji, O. A., & Morakinyo, K. O. (2012). Business structure of indigenous firms in the Nigerian construction industry. International Journal of Business Research and Management, 3(5), 255-264. Odeyinka, H. A., & Yusif, A. (1997). The causes and effects of construction delays on completion cost of housing projects in Nigeria. Journal of Financial Management of Property and Construction, 2, 31-44. Odusami, K. T., Iyagba, R. R. O., & Omirin, M. M. (2003). The relationship between project leadership, team composition and construction project performance in Nigeria. International journal of project management, 21(7), 519-527. Odusami, K. T., Oladiran, O. J., & Ibrahim, S. A. (2012). Evaluation of materials wastage and control in some selected building sites in Nigeria. Emirates Journal for Engineering Research, 17(2), 53-65. OECD (2001), Extended Producer Responsibility: A Guidance Manual for Governments, OECD, Paris. OECD (2005), Analytical Framework for Evaluating the Costs and Benefits of Extended Producer Responsibility Programmes, ENV/EPOC/WGWPR(2005)6/FINAL, OECD, Paris. OECD (Organization for Economic Cooperation and Development) (2008). Measuring Material Flows and Resource Productivity. The OECD Guide, Volume 1. Retrieved from https://www.oecd.org/environment/indicators-modelling-outlooks/MFA- Guide.pdf Official Statistics of Finland (OSF) (2018): Waste statistics [e-publication]. ISSN=2323-5314. 2016. Helsinki: Statistics Finland [referred: 3.3.2019]. Retrieved from http://www.stat.fi/til/jate/2016/jate_2016_2018-08-31_tie_001_en.html Ofori, G. (2000). Greening the construction supply chain in Singapore. European Journal of Purchasing & Supply Management, 6(3), 195-206. Ofori, G. (2012). Developing the Construction Industry in Ghana: the case for a central agency. A concept paper prepared for improving the construction industry in Ghana. National University of Singapore, 3-18. Ogunsesan, D. K. (2004). The Process and Problems of Development Control and Some Remedial Solutions. A Multidisciplinary Journal Environscope. 1(1). Okafor, N., Sunmola, A., Onwuzu, F., Inyang, M., Udoma, M. & Belo-Osagie (2018) Construction and projects in Nigeria: overview. Available at: https://uk.practicallaw.thomsonreuters.com/8-574- 5166?transitionType=Default&contextData=(sc.Default)&firstPage=true&comp=pluk &bhcp=1 Okejiri, E. C. (2011). Strengthening Technology Transfer Capabilities in the Construction Sector in Nigeria. Paper presented at a two day National Workshop. Sept21-22 2011. Westtown Hotel, Ikeja, Lagos, Nigeria. Ola-Adisa, E., Sati, Y. C., & Ojonugwa, I. I. (2015). An Architectural Approach to Solid Waste Management on Selected Building Construction Sites in Bauchi Metropolis. International Journal, 67. Oladapo, A. A. (2007a). A quantitative assessment of the cost and time impact of variation orders on construction projects. Journal of Engineering, Design and Technology, 5(1), pp.35-48.

319

Oladapo, A. A. (2007b). An investigation into the use of ICT in the Nigerian Construction industry. Journal of Information Technology in Construction. 12:261-277. http://www.itcon.org/2007/18 Oladapo, I. O. (1977). Problems of construction industry in Nigeria. IABSE reports of the working commissions. Oladiran, O. (2018). Comparison of the Wastage of Selected Materials on Building Sites with Estimators’ Allowances. Journal of Sustainable Technology, 9(2), 88-98. Oladiran, O. J. (2008). Materials wastage: causes and their contributions’ level. Proceedings of CIB-2008, 15-7. Oladiran, O. J. (2009a). Causes and Minimization Techniques of Materials Waste in Nigerian Construction Process. In Fifth International Conference on Construction in the 21st Century (CITC-V) “Collaboration and Integration in Engineering, Management and Technology” May 20-22, 2009, Istanbul, Turkey. Oladiran, O. J. (2009b). Innovative waste management through the use of waste management plans on construction projects in Nigeria. Architectural Engineering and Design Management, 5(3), 165-176. Olaleye, F., & Abdullah, M., (2014). Influence of Information Technology on the Performance of Small and Medium sized Construction Firms in Nigeria. Research Journal of Business Management & Accounting, 3(2), pp. 21- 27. Olanipekun, A. O. (2017). Motivating project owners to increase their commitment towards improving the delivery performance of green building projects (Doctoral dissertation, Queensland University of Technology). Olatunji, O. A., Sher, W., & Gu, N. (2010). Building information modeling and quantity surveying practice. Emirates Journal for Engineering Research, 15(1), 67-70. Olorunfemi, F. B. (2011). Landfill development and current practices in Lagos metropolis, Nigeria. Journal of Geography and Regional Planning, 4(12), 656. Olotuah, A. O. (2002). Recourse to earth for low-cost housing in Nigeria. Building and environment, 37(1), 123-129. Olowo-Okere, E. (1985). Construction industry in Nigeria. Journal for Building and Civil Engineering Contractors in Nigeria, 2(2), 6-10. Olusegun, A. E., & Michael, A. O. (2011). Abandonment of construction projects in Nigeria: causes and effects. Journal of Emerging Trends in Economics and Management Sciences, 2(2), 142-145. Oluwakiyesi, T. (2011). Construction Industry Report. A Haven of Opportunities. Omole, D. O., & Isiorho, S. A. (2011). Waste management and water quality issues in coastal states of Nigeria: The Ogun State experience. Journal of Sustainable Development in Africa, 13(6), 207-217. Ortiz, O., Castells, F., & Sonnemann, G. (2009). Sustainability in the construction industry: A review of recent developments based on LCA. Construction and building materials, 23(1), 28-39. Ortiz, O., Pasqualino, J. C., & Castells, F. (2010). Environmental performance of construction waste: comparing three scenarios from a case study in Catalonia, Spain. Waste management, 30(4), 646-654. Oskamp, S. (2002). Summarizing sustainability issues and research approaches Psychology of sustainable development (pp. 301-324): Springer. Osmani, M. (2011). Construction waste. In Waste (pp. 207-218). Academic Press.

320

Osmani, M. (2012). Construction waste minimization in the UK: current pressures for change and approaches. Procedia-Social and Behavioural Sciences, 40, 37-40. Osmani, M. (2013). Design waste mapping: a project life cycle approach. Proceedings of the ICE-Waste and Resource Management, 166 (3), pp. 114 - 127. Osmani, M., Glass, J., & Price, A. D. (2006). Architect and contractor attitudes to waste minimisation. In: Proceedings of the Institution of Civil Engineers: Waste and Resource Management 159 (No. WR2), pp. 65–72. Osmani, M., Glass, J., & Price, A.D.F. (2008). Architects’ perspectives on construction waste reduction by design. Waste Management, 28(7): 1147-1158 Osterwalder, A., & Pigneur, Y. (2010). Business model generation: a handbook for visionaries, game changers, and challengers. John Wiley & Sons. Ovaska, J. P., Poutiainen, P., Sorasahi, H., Aho, M., & Annala, J. L. M. (2016). Business Models for a Circular Economy 7 Companies Paving the Way. Overbury, T. (2015). The circular economy at UCL. The Circular Economy in Organisations— University College London, London, 11. Owens, R. (2016). How can our industry waste less and ensure re-use. What we’ve learned at recipro. BuildCircular learning hub, EcoBuild 2016. Owolabi J.D., Amusan L.M., Oloke C., Olusanya, O., Tunji- Olayeni, P.F., Owolabi D., Peter, J., & Omuh I.O. (2014) Causes and Effect of Delay on Project Construction Delivery Time. International Journal of Education and Research, 2(4), 197-208. Oxford Business Group (2015). The Report: Nigeria 2015. Retrieved 24 January 2019 from https://oxfordbusinessgroup.com/nigeria-2015 Oyedele, L. O., Ajayi, S. O., & Kadiri, K. O. (2014). Use of recycled products in UK construction industry: An empirical investigation into critical impediments and strategies for improvement. Resources, Conservation and Recycling, 93, 23-31. Oyedele, L. O., Regan, M., von Meding, J., Ahmed, A., Ebohon, O. J., & Elnokaly, A. (2013). Reducing waste to landfill in the UK: identifying impediments and critical solutions. World Journal of Science, Technology and Sustainable Development, 10(2), 131-142. Oyedele, L. O., Tham, K. W., Fadeyi, M. O., & Jaiyeoba, B. E. (2011). Total building performance approach in building evaluation: Case study of an office building in Singapore. Journal of Energy Engineering, 138(1), 25-30. Oyedele, O. A. (2015). Evaluation of factors affecting construction cost estimation methods in Nigeria. FIG Working Week, Wisdom of the Ages to the Challenges of the Modern World Sofia, Bulgaria, 17-21. Oyenuga, A. A., & Bhamidimarri, R. (2015). Economic Viability of Construction and Demolition Waste Management in terms of Cost Savings-A Case of UK Construction Industry. International Journal of Science and Engineering Investigations, 43(4), 16- 23. Pacheco-Torgal, F., & Jalali, S. (2011). Nanotechnology: advantages and drawbacks in the field of construction and building materials. Construction and building materials, 25(2), 582-590. Pagoropoulos, A., Pigosso, D. C., & McAloone, T. C. (2017). The emergent role of digital technologies in the Circular Economy: A review. Procedia CIRP, 64, 19-24.

321

Palinkas, L. A., Aarons, G. A., Horwitz, S., Chamberlain, P., Hurlburt, M., & Landsverk, J. (2011). Mixed method designs in implementation research. Administration and Policy in Mental Health and Mental Health Services Research, 38(1), 44-53. Pan, S.-Y., Du, M. A., Huang, I.-T., Liu, I.-H., Chang, E., & Chiang, P.-C. (2015). Strategies on implementation of waste-to-energy (WTE) supply chain for circular economy system: a review. Journal of Cleaner Production, 108, 409-421. Papargyropoulou, E., Preece, C., Padfield, R., & Abdullah, A. A. (2011). Sustainable construction waste management in Malaysia: A contractor's perspective. Park, J., & Tucker, R. (2017). Overcoming barriers to the reuse of construction waste material in Australia: a review of the literature. International Journal of Construction Management, 17(3), 228-237. Peansupap, V., & Walker, D. H. (2006). Innovation diffusion at the implementation stage of a construction project: a case study of information communication technology. Construction management and economics, 24(3), 321-332. Pearce, D. (2005). Do we understand sustainable development? Building Research & Information, 33(5), 481-483. Peckenham, E. (2016). 11 Green Building Materials that are way better than concrete. Retrieved from https://inhabitat.com/11-green-building-materials-that-are-way-better- than-concrete/ Peng, C. L., Scorpio, D. E., & Kibert, C. J. (1997). Strategies for successful construction and demolition waste recycling operations. Construction Management & Economics, 15(1), 49-58. Pereira, J. C. (2015). Environmental issues and international relations, a new global (dis) order- the role of International Relations in promoting a concerted international system. Revista Brasileira de Política Internacional, 58(1), 191-209. Persson, O. (2015). What is ciruclar economy?-The discourse of circular economy in the Swedish public sector. Pheng, L. S., & Tan, S. K. (1997). The measurement of just in time wastage for a public housing project in Singapore. Building Research & Information, 25(2), 67-81. Pialot, O., Millet, D., & Bisiaux, J. (2017). “Upgradable PSS”: Clarifying a new concept of sustainable consumption/production based on upgradablility. Journal of cleaner production, 141, 538-550. Pickin, J., & Randell, P. (2017). Australian national waste report 2016. Department of the Environment and Energy. Pitt, M., Tucker, M., Riley, M., & Longden, J. (2009). Towards sustainable construction: promotion and best practices. Construction innovation, 9(2), 201-224. Plagányi, É. E., van Putten, I., Hutton, T., Deng, R. A., Dennis, D., Pascoe, S.…Campbell, R. A. (2013). Integrating indigenous livelihood and lifestyle objectives in managing a natural resource. Proceedings of the National Academy of Sciences, 110(9), 3639-3644. Plano Clark, V. L., & Creswell, J. W. (2011). Designing and conducting mixed methods research. Los Angelos: Sage Publisher. Pokharel, S. (2010). Modeling for energy future: Econometric and backcasting, energy modeling tools and techniques to address sustainable development and climate change. New Delhi: TERI ‐ India Habitat Centre.

322

Polat, G., & Ballard, G. (2004). Waste in Turkish construction: need for lean construction techniques. In Proceedings of the 12th Annual Conference of the International Group for Lean Construction IGLC-12, August, Denmark (pp. 488-501). Polat, G., Damci, A., Turkoglu, H., & Gurgun, A. P. (2017). Identification of root causes of construction and demolition (C&D) waste: The case of Turkey. Procedia engineering, 196, 948-955. Pomponi, F., & Moncaster, A. (2016). Circular economy research in the built environment: A theoretical contribution. In: International Conference on Sustainable Ecological Engineering Design for Society, 14-15 Sep 2016, Leeds Beckett University, UK. Pomponi, F., & Moncaster, A. (2017). Circular economy for the built environment: A research framework. Journal of cleaner production, 143, 710-718. Poon, C. S., & Jaillon, L. (2002). A guide for minimizing construction and demolition waste at the design stage. Dept. of Civil and Structural Engineering. The Hong Kong Polytechnic University. Poon, C. S., Ann, T. W., & Ng, L. H. (2001). On-site sorting of construction and demolition waste in Hong Kong. Resources, conservation and recycling, 32(2), 157-172. Poon, C. S., Yu, A. T., & Jaillon, L. (2004). Reducing building waste at construction sites in Hong Kong. Construction Management and Economics, 22(5), 461-470. Poon, C. S., Yu, A. T., Wong, A., & Yip, R. (2013). Quantifying the impact of construction waste charging scheme on construction waste management in Hong Kong. Journal of construction engineering and management, 139(5), 466-479. Poon, C.S. (2007). Reducing Construction Waste. Waste Management, 27, 1715-1716. Poon, C.S., Yu, T.W., & Ng, L.H. (2001). A Guide for Managing and Minimizing Building and Demolition Waste. The Hong Kong Polytechnic University. Poppelaars, F. (2014). Designing for a circular economy: The conceptual design of a circular mobile device. Circular Economy Innovation Project, Schmidt-MacArthur Fellowship, 2014. Prendeville, S., Sanders, C., Sherry, J., & Costa, F. (2014). Circular economy: is it enough. EcoDesign Centre, Wales, available from: http://www.edcw.org/en/resources/circulareconomy-it-enough Preston, F. (2012). A global redesign? Shaping the circular economy. Energy, Environment and Resource Governance. London: Chatham House. Prieto-Sandoval, V., Jaca, C., & Ormazabal, M. (2018). Towards a consensus on the circular economy. Journal of Cleaner Production, 179, 605-615. Pulaski, M., Hewitt, C., Horman, M., & Guy, B. (2003). Design for deconstruction: Material reuse and constructability. The Pittsburgh Papers: Best of Greenbuild 2003, 74-81. Qian, G., & Wang, C. (2016). Circular Economy Cities. In China's Eco-city Construction (pp. 169-188). Springer, Berlin, Heidelberg. Quist, J. & Vergragt, P. (2001). Multiple sustainable land use: Towards a new sustainable socio‐economic perspective for rural areas, Case Study Report Pathways Project. Delft, the Netherlands: Delft University of Technology. Quist, J., & Vergragt, P. (2006). Past and future of backcasting: the shift to stakeholder participation and a proposal for a methodological framework. Futures, 38(9), 1027- 1045.

323

Quist, J., Knot, M., Young, W., Green, K., & Vergragt, P. (2001). Strategies towards sustainable households using stakeholder workshops and scenarios. International Journal of Sustainable Development 4(1): 75– 89. Rabobank Industry. (2012). Pathways to Circular Economy: A New Model for Food and Agribusiness. The Netherlands. Rabobank Industry. (2015). Pathways to A Circular Economy: What is Possible in the Rotterdam/Delta Region? The Netherlands. Rafee, M. M. (2012). Craft Skills availability in the Nigerian Construction Industry. Journal of the Nigerian Association of Engineering Craftsmen, 7, 8-12. Ragin, C. C., & Becker, H. S. (Eds.). (1992). What is a case? Exploring the foundations of social inquiry. Cambridge university press. Rahimian, F. P., Goulding, J., Akintoye, A., & Kolo, S. (2017). Review of motivations, success factors, and barriers to the adoption of offsite manufacturing in Nigeria. Procedia engineering, 196, 512-519. Rahman, R. (2015). Comparison of telephone and in-person interviews for data collection in qualitative human research. Interdisciplinary Undergraduate Research Journal, 1(1), 10-13. Ramani, K., Ramanujan, D., Bernstein, W. Z., Zhao, F., Sutherland, J., Handwerker, C. ... & Thurston, D. (2010). Integrated sustainable life cycle design: a review. Journal of Mechanical Design, 132(9), 091004. Rao, S.R. (2008, April 23). Factors Influencing Perception. Retrieved from http://www.citeman.com/2849-factors-influencing-perception.html Rashid, N. R. N. A. (2009). Awareness of eco-label in Malaysia’s green marketing initiative. International Journal of Business and Management, 4(8), 132-141. Reh, L. (2013). Process engineering in circular economy. Particuology, 11(2), 119-133. Ren, Y. (2007). The circular economy in China. Journal of Material Cycles and Waste Management, 9(2), 121-129. Renukappa, S., Egbu, C., Akintoye, A., & Goulding, J. (2012). A critical reflection on sustainability within the UK industrial sectors. Construction Innovation, 12(3), 317- 334. Richards, L., & Morse, J. M. (2012). Readme first for a user's guide to qualitative methods. Sage. Riley, D. R., Varadan, P., James, J. S., & Thomas, H. R. (2005). Benefit-cost metrics for design coordination of mechanical, electrical, and plumbing systems in multistorey buildings. Journal of Construction Engineering and Management, 131(8), 877-889. Rizos, V., Behrens, A., Kafyeke, T., Hirschnitz-Garbera, M., & Ioannou, A. (2015). The Circular Economy: Barriers and Opportunities for SMEs. CEPS Working Documents No. 412/September 2015. Rizos, V., Tuokko, K., & Behrens, A. (2017). The Circular Economy: A review of definitions, processes and impacts. CEPS Research Report No 2017/8, April 2017. Robèrt, K., Göran B., David W., Henrik N., Sophie B., David C., Lena J., Jonas O., George B., Hördur H., Jamie M., Brendan M., Tamara C., & Merlina M. (2010). Strategic Leadership towards Sustainability. 6th ed. Karlskrona, Sweden: Psilanders grafiska. Robinson, J. (2003). Future subjunctive: backcasting as social learning. Futures, 35(8), 839- 856.

324

Robinson, O. C. (2014). Sampling in interview-based qualitative research: A theoretical and practical guide. Qualitative research in psychology, 11(1), 25-41. Robson, D., & Robson, M. (2000). Ethical issues in Internet counselling. Counselling Psychology Quarterly, 13(3), 249-257. Rogers, E. M. (1995). Diffusion of Innovations. New York, NY: Free Press. Rogers, E. M. (2003). Diffusion of innovation (5th ed.). New York: Free Press. Royal Institute of British Architects (2012) BIM Overlay to the RIBA Outline Plan of Work. http://www.bdonline.co.uk/Journals/2012/05/15/d/x/f/BIM_Overlay_RIBA_Plan_of_ Work_Embargoed.pdf Royal Institute of British Architects (2013). Work Stages. Retrieved from https://www.liverpool.ac.uk/media/livacuk/facilities-management/policies-and- procedures/RIBA_workstages.pdf RSA (Royal Society for the encouragement of Arts, Manufactures and Commerce) (2013). Investigating the Role of Design in the Circular Economy. Accessed 16 December 2016 from http://tinyurl.com/q2q43sg Ruchi, H. (2012). Skills knowledge and organizational performance. Research paper, 3. November, 2012. Ruya, F., Chitumu, D., & Sharon, J. (2017). Construction Standard and Regulation in Nigeria. In Proceedings of FIG Working Week 2017 – Surveying the world of tomorrow – From digitalisation to augmented reality. May 29 – June 2, 2017, Helsinki, Finland. Sabol, L. (2008). Challenges in cost estimating with Building Information Modelling. IFMA World Workplace, 1-16. Sacks, R., Koskela, L., Dave, B. A., & Owen, R. (2010). Interaction of lean and building information modelling in construction. Journal of construction engineering and management, 136(9), 968-980. Sacks, R., Radosavljevic, M., & Barak, R. (2010). Requirements for building information modeling based lean production management systems for construction. Automation in construction, 19(5), 641-655. Sahin, I. (2006). Detailed review of Rogers' diffusion of innovations theory and educational technology-related studies based on Rogers' theory. TOJET: The Turkish Online Journal of Educational Technology, 5(2). Sakai, S.-i., Yoshida, H., Hirai, Y., Asari, M., Takigami, H., Takahashi, S. . . . Chi, N. (2011). International comparative study of 3R and waste management policy developments. Journal of Material Cycles and Waste Management, 13(2), 86-102. doi: 10.1007/s10163-011-0009-x Sammalisto, K., & Brorson, T. (2008). Training and communication in the implementation of environmental management systems (ISO 14001): a case study at the University of Gävle, Sweden. Journal of Cleaner Production, 16(3), 299-309. Sanchez, B., & Haas, C. (2018a). Capital project planning for a circular economy. Construction Management and Economics, 36(6), 303-312. Sanchez, B., & Haas, C. (2018b). A novel selective disassembly sequence planning method for adaptive reuse of buildings. Journal of Cleaner Production, 183, 998-1010. Saraiva, T. S.; Borges, M.M.; Filho, A.C. (2012). The Importance of Recycling of Construction and Demolition Waste. Proceedings of PLEA2012 - 28th Conference, Opportunities, Limits & Needs towards an environmentally responsible architecture, Lima, Perú 7-9 November 2012.

325

Sardén, Y., & Engström, S. (2010). Modern methods of construction: a solution for an industry characterised by uncertainty? In Annual ARCOM Conference: 06/09/2010- 08/09/2010 (pp. 1101-1110). Association of Researchers in Construction Management. Sassi, P., & Thompson, M. W. (1998). Summary of a study on the potential of recycling in the building industry and the development of an indexing system to assess the suitability of materials for recycling and the benefits from recycling. In Proceedings of the Eurosolar conference. Saunders, M. N., & Townsend, K. (2016). Reporting and justifying the number of interview participants in organization and workplace research. British Journal of Management, 27(4), 836-852. Saunders, M., Lewis, P., & Thornhill, A. (2007). Research methods for business students: Pearson Education UK. Saunders, M., Lewis, P., & Thornhill, A. (2009). Understanding research philosophies and approaches. Research Methods for Business Students, 4, 106-135. Sauvé, S., Bernard, S., & Sloan, P. (2016). Environmental sciences, sustainable development and circular economy: Alternative concepts for trans-disciplinary research. Environmental Development, 17, 48-56. Schaltegger, S., Lüdeke-Freund, F., & Hansen, E. G. (2012). Business cases for sustainability: the role of business model innovation for corporate sustainability. International Journal of Innovation and Sustainable Development, 6(2), 95-119. Scheepens, A. E., Vogtländer, J. G., & Brezet, J. C. (2016). Two life cycle assessment (LCA) based methods to analyse and design complex (regional) circular economy systems. Case: Making water tourism more sustainable. Journal of Cleaner Production, 114, 257-268. Schepelmann, P. (2009). Lifecycle assessment (LCA). Wuppertal Institute for Climate, ed., Coordination Action for innovation in Life Cycle Analysis for Sustainability-CALCAS. Schnitzer, H., & Ulgiati, S. (2007). Less bad is not good enough: approaching zero emissions techniques and systems. Schober, P., Boer, C., & Schwarte, L. A. (2018). Correlation coefficients: appropriate use and interpretation. Anesthesia & Analgesia, 126(5), 1763-1768. Schulte, U. G. (2013). New business models for a radical change in resource efficiency. Environmental Innovation and Societal Transitions, 9, 43-47. Scotland, Z. W. (2016). Zero Waste Scotland. Seeley, I. H. (1997). Quantity surveying practice. Macmillan International Higher Education. Senaratne, S., & Wijesiri, D. (2008). Lean Construction as a Strategic Option: Testing its Suitability and Acceptability in Sri Lanka. Lean Construction Journal. Seo, S., & Hwang, Y. (1999). An estimation of construction and demolition debris in Seoul, Korea: waste amount, type, and estimating model. Journal of the Air & Waste Management Association, 49(8), 980-985. Sfakianaki, E. (2015). Resource-efficient construction: Rethinking construction towards sustainability. World Journal of Science, Technology and Sustainable Development, 12(3), 233-242. Sharma, A. (2013, December 31). Perception: Meaning, Definition, Principles and Factors Affecting in Perception. Retrieved from http://www.psychologydiscussion.net/perception/perception-meaning-definition- principles-and-factors-affecting-in-perception/634

326

Shelden, D. (2013). Networked Space. Architectural design, 83(2), 36-41. Shen, L. Y., & Tam, V. W. (2002). Implementation of environmental management in the Hong Kong construction industry. International Journal of Project Management, 20(7), 535- 543. Shen, L., Song, S., Hao, J., & Tam, V. W. (2008). Collaboration among Project Participants towards Sustainable Construction- A Hong Kong Study. Open Construction and Building Technology Journal, 2, 59-68. Sherwin, C., & Evans, S. (2000). Ecodesign innovation: is' early' always' best’? In Proceedings of the 2000 IEEE International Symposium on Electronics and the Environment (Cat. No. 00CH37082) (pp. 112-117). IEEE. Sheth, K. N. (2016, February). Sustainable Building Materials Used in Green Buildings. In 9th International Conference on Engineering and Business Education (ICEBE) & 6th International Conference on Innovation and Entrepreneurship (ICIE) (pp. 23-26). Shi, L., Xing, L., Bi, J., & Zhang, B. (2006). Circular economy: a new development strategy for sustainable development in China. Paper presented at the Proc. Third World Congress of Environmental and Resource Economists, Japan. Sica, G.T. (2006). Bias in research studies. Radiology, 3:780–9. Sichali, M., & Banda, L. J. (2017). Awareness, Attitudes and Perception of Green Building Practices and Principles in the Zambian Construction Industry'. International Journal of Construction Engineering and Management, 6(5), 215-220. Silva, A., Rosano, M., Stocker, L., & Gorissen, L. (2017). From waste to sustainable materials management: Three case studies of the transition journey. Waste management, 61, 547- 557. Simpson, C. (2016). This Aussie Robot can 3D Print a House using Bricks. Retrieved 30 January 2018 from https://www.gizmodo.com.au/2016/07/this-aussie-robot-can-3d- print-a-house-using-bricks/ Simundić, A. M. (2013). Bias in research. Biochemia medica, 23(1), 12–15. doi:10.11613/BM.2013.003 Si-yuan, W., & Yuan, D. (2012). The Development and Countermeasures of Circular Economy in Gansu Province. Skoyles, E. R., & Skoyles, J. R. (1987). Waste prevention on site. BT Batsford Limited. Slonim-Nevo, V., & Nevo, I. (2009). Conflicting findings in mixed methods research: an illustration from an Israeli study on immigration. Journal of Mixed Methods Research, 3(2), 109-128. Small and Medium Enterprises Development Agency (SMEDAN) Act (2003). Federal Republic of Nigeria. SMEDAN, (2012). Survey report on micro, small and medium enterprises in Nigeria. Nigerian Bureau of statistics and small and medium enterprises development agency of Nigeria. Smith, J. & Noble, H. (2014). Bias in research. Evidence-based nursing, 17(4), 100-101. Smol, M., Kulczycka, J., Henclik, A., Gorazda, K., & Wzorek, Z. (2015). The possible use of sewage sludge ash (SSA) in the construction industry as a way towards a circular economy. Journal of Cleaner Production, 95, 45-54. Solís-Guzmán, J., Marrero, M., Montes-Delgado, M. V., & Ramírez-de-Arellano, A. (2009). A Spanish model for quantification and management of construction waste. Waste Management, 29(9), 2542-2548.

327

Somorin, T. O., Adesola, S., & Kolawole, A. (2017). State-level assessment of the waste-to- energy potential (via incineration) of municipal solid wastes in Nigeria. Journal of Cleaner Production, 164, 804-815. Song, Q., Li, J., & Zeng, X. (2015). Minimizing the increasing solid waste through zero waste strategy. Journal of Cleaner Production, 104, 199-210. doi: http://dx.doi.org/10.1016/j.jclepro.2014.08.027 Sonuga, F., Aliboh, O., & Oloke, D. (2002). Particular barriers and issues associated with projects in a developing and emerging economy. Case study of some abandoned water and irrigation projects in Nigeria. International Journal of project management, 20(8), 611-616. Spain, M. E. (2001). Plan Nacional de Residuos de Construcción y Demolición 2001–2006 (National C&D waste plan 2001–2006). Ministry of the Environment, Madrid. Stahel, W. (2010). The performance economy (Vol. 572): Palgrave Macmillan London. Stahel, W. (2013). Policy for material efficiency—sustainable taxation as a departure from the throwaway society. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 371(1986), 20110567. Stahel, W. R. (2016). The circular economy. Nature News, 531(7595), 435. Stangor, C. (1998). Research Methods for the Behavioural Sciences. Boston, MA: Houghton Mifflin. Statista (2019). Number of Social Network Users in Nigeria from 2017 to 2023 (in millions). Retrieved 19 February 2019 from https://www.statista.com/statistics/972907/number- of-social-network-users-in-nigeria/ Sterner, E. (2000). Life-cycle costing and its use in the Swedish building sector. Building Research & Information, 28(5-6), 387-393. Stocks, T. (2018) Modern Methods of Construction - Disruption to Traditional Methods? Retrieved 20 January 2019 from https://www.fgould.com/uk-europe/articles/modern- methods-of-construction-disruption-to-tr/ Stott, R. N., Stone, M., & Fae, J. (2016). Business models in the business-to-business and business-to-consumer worlds–what can each world learn from the other? Journal of Business & Industrial Marketing, 31(8), 943-954. Strandberg, C. (2012). Critical Success Factors for Sustainable Purchasing. Accessed 21 January 2019 from: http://corostrandberg.com/wp-content/uploads/files/Critical- Success-Factors-for-Sustainable-Purchasing.pdf Strydom, W. (2018). Applying the Theory of Planned Behavior to recycling behavior in South Africa. Recycling, 3(3), 43. Stuart, T. E. (2000). Interorganizational alliances and the performance of firms: A study of growth and innovation rates in a high-technology industry. Strategic management journal, 21(8), 791-811. Studer, S., Welford, R., & Hills, P. (2006). Engaging Hong Kong businesses in environmental change: drivers and barriers. Business Strategy and the Environment, 15(6), 416-431. Su, B., Heshmati, A., Geng, Y., & Yu, X. (2013). A review of the circular economy in China: moving from rhetoric to implementation. Journal of Cleaner Production, 42, 215-227. doi: http://dx.doi.org/10.1016/j.jclepro.2012.11.020 Suleiman, I. J., & Luvara, V. G. (2016). Factors influencing change of design of building projects during construction stage in Dar-es-salaam Tanzania. International Journal of Construction Engineering and Management, 5(4), 93-101.

328

Sutrisna, M. (2004). Developing a knowledge based system for the valuation of variations on civil engineering works (Doctoral dissertation, University of Wolverhampton). Svensson, G. (2015). Contemporary process to test the theory of a research model through covariance-based structural equation modeling in business research: is it science, quasi- science or just non-science…?. European Business Review, 27(4), 447-458. Taiwo, E.A. (2011). Building Laws, Contracts and Administration. Osogbo: Oyweck Publication. Takim, R., Akintoye, A., & Kelly, J. (2004). Analysis of measures of construction project success in Malaysia. In Proceedings of the 20th Annual ARCOM Conference in Heriot Watt University, Association of Researchers in Construction Management, Edinburgh, 2 (1-3), pp. 1123-1133. Tam, V. W. (2008a). On the effectiveness in implementing a waste-management-plan method in construction. Waste management, 28(6), 1072-1080. Tam, V. W. (2008b). Economic comparison of concrete recycling: A case study approach. Resources, Conservation and Recycling, 52(5), 821-828. Tam, V. W., & Tam, C. M. (2006). A review on the viable technology for construction waste recycling. Resources, conservation and recycling, 47(3), 209-221. Tam, V. W., Shen, L. Y., & Tam, C. M. (2007). Assessing the levels of material wastage affected by sub-contracting relationships and projects types with their correlations. Building and environment, 42(3), 1471-1477. Tam, V. W., Shen, L. Y., Fung, I. W., & Wang, J. Y. (2007). Controlling construction waste by implementing governmental ordinances in Hong Kong. Construction Innovation, 7(2), 149-166. Tam, V. W., Tam, C. M., Zeng, S. X., & Ng, W. C. (2007). Towards adoption of prefabrication in construction. Building and environment, 42(10), 3642-3654. Tam, V.W.Y., & Tam, C.M. (2008). Waste reduction through incentives: A case study. Building Research & Innovation, 36(1), 37 – 43. Tang, H. H., & Larsen, I. B. (2004). Managing Construction Waste-A Sarawak Experience. DANIDA/Sarawak Government UEMS Project. Natural Resources and Environmental Board (NREB). Tang, X., Simon S., Benjamin C., McLellan, & Mikael H. (2015). Clean coal use in China: challenges and policy implications. Energy Policy 87: 517-523. Tashakkori, A., & Teddlie, C. (1998). Mixed methodology: Combining qualitative and quantitative approaches (Vol. 46). Sage. Tashakkori, A., & Teddlie, C. (2003). Handbook on mixed methods in the behavioral and social sciences. Sage. Taylor, J. E., & Levitt, R. (2007). Innovation alignment and project network dynamics: An integrative model for change. Project management journal, 38(3), 22-35. Taylor, J., & Levitt, R. (2004). Understanding and managing systemic innovation in project- based industries. Innovations: Project management research, 83-99. Teddlie, C., & Tashakkori, A. (2003). Major issues and controveries inthe use of mixed methods in the social and behavioural sciences. Handbook of mixed methods in social & behavioral research, 3-50. Teddlie, C., & Tashakkori, A. (2009). Foundations of mixed methods research: Integrating quantitative and qualitative approaches in the social and behavioral sciences. Sage.

329

Teo, M. M. M., & Loosemore, M. (2001). A theory of waste behaviour in the construction industry. Construction Management and Economics, 19(7), 741-751. Thollander, P., Rohdin, P., Moshfegh, B., Karlsson, M., Söderström, M., and Trygg, L. (2013). Energy in Swedish industry 2020—Current status, policy instruments, and policy implications. Journal of Cleaner Production 51: 109– 117. Thomas, C., Setién, J., Polanco, J., Alaejos, P., & De Juan, M. S. (2013). Durability of recycled aggregate concrete. Construction and Building Materials, 40, 1054-1065. Thongkamsuk, P., Sudasna, K., & Tondee, T. (2017). Waste generated in high-rise buildings construction: A current situation in Thailand. Energy Procedia, 138, 411-416. Thornback, J., & Adams, K. (2016). Knowledge resource for circular economy thinking in construction. The Green Construction Board. Green Construction Board, London, UK. See http://www.greenconstructionboard.org/images/stories/112212%20GCB%20Circular %20Economy% 20April%202016%20v3.pdf Timmermans, F. (2015). First Vice-President Timmermans’ and Vice-President Katainen’s opening remarks at the presentation of the Circular Economy package. Tilgjengelig fra http://europa.eu/rapid/pressrelease_SPEECH-15-6238_en.htm Tingley, D. D., & Davison, B. (2011). Design for deconstruction and material reuse. Proceedings of the Institution of Civil Engineers-Energy, 164(4), 195-204. Turner, J. P. (2006). Rock-socketed shafts for highway structure foundations (Vol. 360): Transportation Research Board. U.S. E.P.A (2016): Advancing sustainable materials management: 2014 fact sheet. United States Environ Prot Agency Off L Emerg Manag Washington, DC 20460 2016, November: 22. Ubleble, B.A., & Gbenemene, K. (2017). Cognitive Development in Children and Environmental Leadership Project for a Sustainable Development in the Niger Delta Region of Nigeria. Int. Journal of Innovative Psychology and Social Dev. 5(4): 21-33. Ugheru, D.C. (2006). Training of craftsmen for Nigeria construction industry. Journal of the Nigerian Association of Engineering Craftsmen, 5; 9-10. Ugochukwu, S. C., & Onyekwena, T. (2014). Participation of indigenous contractors in Nigerian public sector construction projects and their challenges in managing working capital. International Journal of Civil Engineering, Construction and Estate Management, 1(1), 1-21. UK Green Building Council (2018). Circular Economy. Retrieved from https://www.ukgbc.org/ukgbc-work/circular-economy/ UNEP & Sida (2006). Applying Cleaner Production to MEAs – Global Status Report, United Nations Environment Programme, Division of Technology, Industry and UNEP (2013). Metal Recycling: Opportunities, Limits, Infrastructure. A Report of the Working Group on the Global Metal Flows to the International Resource Panel. Reuter, M.A., Hudson, C., van Schaik, A., Heiskanen, K., Meskers, C., Hagelüken, C. UNEP. (2006). Circular Economy: An alternative model for economic development (I. Division of Technology, and Economics, Trans.). France: United Nations Environment Programme. UNIDO (2014). Cleaner Production (CP). Retrieved 14 January 2018 from http://www.unido.org/en/what-we-do/environment/resource-efficient-and-low-carbon- industrial-production/cp/cleaner-production.html

330

United Nations (2015a). World Population Prospects, the 2015 Revision (D. o. E. a. S. A. P. Division, Trans.) (ESA/P/WP.241 ed.). New York: United Nations. United Nations (2015b). About the Sustainable Development Goals. Retrieved from: https://www.un.org/sustainabledevelopment/sustainable-development-goals/ United Nations (2017). Nigeria: Voluntary National Review. Retrieved from: https://sustainabledevelopment.un.org/memberstates/nigeria Uygunoğlu, T., Topçu, İ. B., & Çelik, A. G. (2014). Use of waste marble and recycled aggregates in self-compacting concrete for environmental sustainability. Journal of Cleaner Production, 84, 691-700. Van Berkel, R. (2000, May). Sustainable development and cleaner production in minerals and energy production. In Sixth International Symposium on Environmental Issues and Waste Management in Energy and Mineral Production (pp. 1-17). Van Berkel, R., Willems, E., & Lafleur, M. (1997). The relationship between cleaner production and industrial ecology. Journal of Industrial Ecology, 1(1), 51-66. Van den Berg, M., & Bakker, C. (2015). A product design framework for a circular economy. Paper presented at the Proceedings of the PLATE Conference, Nottingham, UK, 17-19 June 2015. Van Erp, G., & Rogers, D. (2008). A highly sustainable fibre composite building panel. In Proceedings of the international workshop on fibre composites in civil infrastructure–past, present and future (pp. 1-2). Van Ewijk, S., & Stegemann, J. A. (2016). Limitations of the waste hierarchy for achieving absolute reductions in material throughput. Journal of Cleaner Production, 132, 122- 128. Van Houtven, G. L., & Morris, G. E. (1999). Household behaviour under alternative pay-as- you-throw systems for solid waste disposal. Land Economics, 515-537. van Sante, M. (2017) ‘Circular Construction’, Retrieved from https://www.ing.nl/media/ING_EBZ_Circular-construction_Opportunities-for- demolishers-and-wholesalers_juni-2017_tcm162-127568.pdf Vasantha, G. V. A., Roy, R., & Corney, J. R. (2016). Advances in designing product-service systems. Journal of the Indian Institute of Science, 95(4), 429-448. Veronesi, G., & Keasey, K. (2009). Policy implementation and stakeholder involvement within the National Health Service. Leeds, Leeds University. Vieira, C. S., & Pereira, P. M. (2015). Use of recycled construction and demolition materials in geotechnical applications: A review. Resources, Conservation and Recycling, 103, 192-204. Vilches, A., Garcia-Martinez, A., & Sanchez-Montañes, B. (2017). Life cycle assessment (LCA) of building refurbishment: A literature review. Energy and Buildings, 135, 286- 301. Vinci (n.d.). Green Products and Services. Retrieved October 20, 2018 from https://www.vinci.com/vinci.nsf/en/sustainabledevelopment/pages/green_products_and_services.htm Vladimir, G., & Przemysław, D. (2017). European circular construction alliance-adopting circular economy for internationalization and global competitiveness of European SMEs in building and construction. Von Bertalanffy, L. (1950). An outline of general system theory. British Journal for the Philosophy of science.

331

Von Bertalanffy, L. (1968). General system theory. New York, 41973(1968), 40. Wahab, A. B., & Lawal, A. F. (2011). An evaluation of waste control measures in construction industry in Nigeria. African Journal of Environmental Science and Technology, 5(3), 246-254. Walker, J. L. (2012). Research column. The Use of Saturation in Qualitative Research. Canadian Journal of Cardiovascular Nursing, 22(2). Wallace, W. L. (1971). The Logic of Science in Sociology [sound Recording]: Transaction Publishers. Walls, M. (2004). EPR policy goals and policy choices: what does economics tell us? Economic Aspects of Extended Producer Responsibility, (Part 1). Walls, M. (2006). Extended producer responsibility and product design: Economic theory and selected case studies. Wan, S. K., & Kumaraswamy, M. M. (2012). Improving building services coordination at the pre-installation stage. Engineering, Construction and Architectural Management, 19(3), 235-252. Wang, C. Q., Wang, H., Liu, Q., Fu, J. G., & Liu, Y. N. (2014). Separation of polycarbonate and acrylonitrile–butadiene–styrene waste plastics by froth flotation combined with ammonia pretreatment. Waste management, 34(12), 2656-2661. Wang, J. Y., Kang, X. P., & Tam, V.W.Y (2008). An investigation of construction wastes: an empirical study in Shenzhen. Journal of Engineering, Design and Technology, 6(3), 227-236. Wang, J. Y., Touran, A., Christoforou, C., & Fadlalla, H. (2004). A systems analysis tool for construction and demolition wastes management. Waste management, 24(10), 989- 997. Wang, J., Li, Z., & Tam, V. W. (2014). Critical factors in effective construction waste minimization at the design stage: a Shenzhen case study, China. Resources, Conservation and Recycling, 82, 1-7. Wang, L.-y. (2009). Development Standard and Evaluation of Circular Economy on Chinese Cities—Positive Analysis Based on 29 Cities [J]. Journal of Shanxi Finance and Economics University, 5, 004. Wang, R., & Simeone, G. (2005). Circular Economy: Principles and Practices in Europe and China. Watson, M. (2008). The materials of consumption. Journal of Consumer Culture, 8(1): 5-10, 1469-5405 DOI: 10.1177/1469540507085668 WCED (1987). Our common future. World Commission on Environment and Development Oxford University Press. Webster, K. (2015). The Circular Economy: A Wealth of Flows. Ellen MacArthur Foundation, Isle of Wight. Wen, Z., & Li, R. (2010). Materials metabolism analysis of China's highway traffic system (HTS) for promoting circular economy. Journal of Industrial Ecology, 14(4), 641-649. Wen, Z., & Meng, X. (2015). Quantitative assessment of industrial symbiosis for the promotion of circular economy: a case study of the printed circuit boards industry in China's Suzhou New District. Journal of Cleaner Production, 90, 211-219. Wheaton, W.G. (2017). Designing for Disassembly in the Built Environment (Master’s Thesis, University of Washington, Seattle, WA, USA).

332

Whyte, J. (2012). Building Information Modelling in 2012: Research Challenges, Contributions, and Opportunities. Des Innov Res Cent Work Pap, 5, 1-22. Widén, K. (2002). Innovation in the Construction Process: A theoretical framework (Doctoral dissertation, Division of Construction Management, Lund Institute of Technology). Widen, K., & Hansson, B. (2007). Diffusion characteristics of private sector financed innovation in Sweden. Construction Management and Economics, 25(5), 467-475. Wijkman, A., & Skånberg, K. (2015). The circular economy and benefits for society. Club of Rome. Williams, B., Brown, T., & Boyle, M. (2012). Construct validation of the readiness for Interprofessional learning scale: a Rasch and factor analysis. Journal of interprofessional care, 26(4), 326-332. Wilson, D. C. (2007). Development drivers for waste management. Waste Management & Research, 25(3), 198-207. Wilson, J. (2014). Essentials of business research: A guide to doing your research project. Sage. Wilson, L. (2015). The sustainable future of the Scottish textiles sector: challenges and opportunities of introducing a circular economy model. Textiles and Clothing Sustainability, 1(1), 1-9. doi: 10.1186/s40689-015-0005-y Winans, K., Kendall, A., & Deng, H. (2017). The history and current applications of the circular economy concept. Renewable and Sustainable Energy Reviews, 68, 825-833. Womack, J. P., & Jones, D. T. (1996). Beyond Toyota: how to root out waste and pursue perfection. Harvard business review, 74(5), 140-158. Wong, E. O., & Yip, R. C. (2004). Promoting sustainable construction waste management in Hong Kong. Construction Management and Economics, 22(6), 563-566. Wong, J. K. W., San Chan, J. K., & Wadu, M. J. (2016). Facilitating effective green procurement in construction projects: An empirical study of the enablers. Journal of cleaner production, 135, 859-871. Woods, M. (2011). Interviewing for research and analysing qualitative data: An overview. Massey University. Wooi, G. C., & Zailani, S. (2010). Green supply chain initiatives: investigation on the barriers in the context of SMEs in Malaysia. International Business Management, 4(1), 20-27. World Bank, G. (2012). Urban Development Series - Knowledge Papers, Waste Generation. World Bank, G. (2013). Doing Business 2013. Nigeria – Country Profile. Retrieved 02 February 2016, from The World Bank Group http://data.worldbank.org/country/nigeria World Bank, G. (2016). Nigeria. Retrieved 02 February 2019, from The World Bank Group http://data.worldbank.org/country/nigeria World Bank, G. (2018a). Solid Waste Management. Retrieved 4 January 2019 from http://www.worldbank.org/en/topic/urbandevelopment/brief/solid-waste-management World Bank, G. (2018b). Nigeria. Retrieved 02 February 2019, from The World Bank Group http://data.worldbank.org/country/nigeria World Economic Forum (WEF) (2016). Circular Economy. Retrieved from https://www.weforum.org/global-challenges/projects/circular-economy/ World Resource Institute (2014). Policy and Action Standard and Mitigation Goals Standard: Pilot Testing Summary. WRAP (2007a). Waste Minimisation in Construction: Reducing Material Wastage in Construction. Banbury, UK.

333

WRAP (2007b). Achieving effective waste minimisation through design: Guidance on designing out waste for construction clients, design teams and contractors (online). Retrieved from http://www2.wrap.org.uk/downloads/Design_FINAL.67813ab5.4821.pdf WRAP (2008). Net Waste Tool (Online). Retrieved from http://nwtool.wrap.org.uk/Documents/WRAP%20NW%20Tool%20Data%20Report.p df WRAP (2008). The Courtauld Commitment. Available at: http://www.wrap.org.uk/retail/courtauldcommitment/index.html WRAP (2009a). Designing out waste: A design team guide for buildings (online). Retrieved from http://www.modular.org/marketing/documents/DesigningoutWaste.pdf WRAP (2009b). Materials Change for Better Environment: Achieving Good Practice Waste Minimisation and Management (Guidance for construction clients, design teams and contractors). Banbury, UK. WRAP (2009c). Delivering higher recycled content in construction projects (online). Retrieved from http://www.wrapni.org.uk/sites/files/wrap/Delivering%20higher%20recycled%20cont ent%20in%20construction%20projects.pdf WRAP (2010). Final Report: Waste arising in the supply of food and drink to households in the UK, March, 2010. Retrieved 10 September 2018 from http:// www.wrap.org.uk/downloads/RSC002-005_March_25_2010_ FINAL.17a54561.8904.pdf WRAP (2010a). Designing out Waste Tool for Buildings (DoWT-B) (online). Retrieved from http://www.wrap.org.uk/sites/files/wrap/DoWT-B%20User%20Guide.pdf WRAP (2013). Built Environment Circular Economy. Retrieved 2 January. 2019 from http://www.wrap.org.uk/sites/files/wrap/WRAP%20Built%20Environment%20%20C ircular%20Economy%20Jan%202013.pdf Wright, B. E., Manigault, L. J., & Black, T. R. (2004). Quantitative Research Measurement in Public Administration. An Assessment of Journal Publications. Administration & Society, 35(6), 747-764. Wu, C., Xu, B., Mao, C., & Li, X. (2017). Overview of BIM maturity measurement tools. Journal of Information Technology in Construction (ITcon), 22(3), 34-62. Wu, H. Q., Shi, Y., Xia, Q., & Zhu, W. D. (2014). Effectiveness of the policy of circular economy in China: A DEA-based analysis for the period of 11th five-year- plan. Resources, conservation and recycling, 83, 163-175. Wysokińska, Z. (2016). The “new” environmental policy of the European Union: A path to development of a circular economy and mitigation of the negative effects of climate change. Comparative Economic Research, 19(2), 57-73. Xiahou, X., Yuan, J., Liu, Y., Tang, Y., & Li, Q. (2018). Exploring the driving factors of construction industrialization development in China. International journal of environmental research and public health, 15(3), 442. Xie, H., Shi, W., & Issa, R. R. (2010). Implementation of BIM/RFID in computer-aided design- manufacturing-installation process. In 2010 3rd International Conference on Computer Science and Information Technology (Vol. 2, pp. 107-111). IEEE.

334

Xinan, L., & Yanfu, L. (2011). Driving Forces on China's Circular Economy: From Government's perspectives. Energy Procedia, 5, 297-301. doi: http://dx.doi.org/10.1016/j.egypro.2011.03.051 Xing, Y., Brewer, M., El-Gharabawy, H., Griffith, G., & Jones, P. (2018, February). Growing and testing mycelium bricks as building insulation materials. In IOP Conference Series: Earth and Environmental Science (Vol. 121, No. 2, p. 022032). IOP Publishing. Xue, B., Chen, X.-p., Geng, Y., Guo, X.-j., Lu, C.-p., Zhang, Z.-l., & Lu, C.-y. (2010). Survey of officials’ awareness on circular economy development in China: Based on municipal and county level. Resources, Conservation and Recycling, 54(12), 1296-1302. doi: http://dx.doi.org/10.1016/j.resconrec.2010.05.010 Xue, H., Zhang, S., Su, Y., & Wu, Z. (2017). Factors affecting the capital cost of prefabrication - A case study of China. Sustainability, 9(9), 1512. Yan, W., Culp, C., & Graf, R. (2011). Integrating BIM and gaming for real-time interactive architectural visualization. Automation in Construction, 20(4), 446-458. Yana, A. G. A., Rusdhi, H. A., & Wibowo, M. A. (2015). Analysis of factors affecting design changes in construction project with Partial Least Square (PLS). Procedia Engineering, 125, 40-45. Yang, B. D., & Kim, L. S. (2005). A low-power CAM using pulsed NAND-NOR match-line and charge-recycling search-line driver. IEEE Journal of Solid-State Circuits, 40(8), 1736-1744. Yang, J., Du, Q., & Bao, Y. (2011). Concrete with recycled concrete aggregate and crushed clay bricks. Construction and Building Materials, 25(4), 1935-1945. Yang, S., & Feng, N. (2008). A case study of industrial symbiosis: Nanning Sugar Co., Ltd. in China. Resources, Conservation and Recycling, 52(5), 813-820. Yao, H. (2009). A dynamic approach for evaluating the sustainability performance of infrastructure projects. The Hong Kong Polytechnic University. Yap, N. T. (2005). Towards a Circular Economy: Progress and Challenges. Greener Management International, (50), 11-24. Retrieved from http://www.jstor.org/stable/greemanainte.50.11 Yeasmin, S., & Rahman, K. F. (2012). Triangulation research method as the tool of social science research. BUP journal, 1(1), 154-163. Yellishetty, M., Mudd, G. M., Ranjith, P. G., & Tharumarajah, A. (2011). Environmental lifecycle comparisons of steel production and recycling: sustainability issues, problems and prospects. Environmental science & policy, 14(6), 650-663. Yin, B. C. L., Laing, R., Leon, M., & Mabon, L. (2018). An evaluation of sustainable construction perceptions and practices in Singapore. Sustainable cities and society, 39, 613-620. Ying, J., & Li-jun, Z. (2012). Study on green supply chain management based on circular economy. Physics Procedia, 25, 1682-1688. Yong, R. (2007). The circular economy in China. Journal of material cycles and waste management, 9(2), 121-129. Youssef, M. M. S., Mallet, C., Chehata, N., Le Bris, A., & Gressin, A. (2014, July). Combining top-down and bottom-up approaches for building detection in a single very high resolution satellite image. In Geoscience and Remote Sensing Symposium (IGARSS), 2014 IEEE International (pp. 4820-4823).

335

Yuan, H. (2013a). A SWOT analysis of successful construction waste management. Journal of Cleaner Production, 39, 1-8. Yuan, H. (2013b). Critical management measures contributing to construction waste management: Evidence from construction projects in china. Project Management Journal, 44(4), 101-112. Yuan, H., Shen, L., & Wang, J. (2011). Major obstacles to improving the performance of waste management in China's construction industry. Facilities, 29(5/6), 224-242. Yuan, Y. Y. (2013). Adding environmental sustainability to the management of event tourism. International Journal of Culture, Tourism and Hospitality Research, 7(2), 175-183. Yuan, Z., Bi, J., & Moriguichi, Y. (2006). The circular economy: A new development strategy in China. Journal of Industrial Ecology, 10(1‐2), 4-8. Yunyan, L., & Biao, Z. (2014). Innovation and Development Strategies of Investment and Financing Modes for Circular Economy. Meteorological and Environmental Research, 5(6), 50. Yvonne Feilzer, M. (2010). Doing mixed methods research pragmatically: Implications for the rediscovery of pragmatism as a research paradigm. Journal of mixed methods research, 4(1), 6-16. Zayko, M. (2006). A systematic view of lean principles: reflection on the past 16years of lean thinking and learning. New York: Lean Thinkers‟ Corner, Lean Enterprise Institute. Zhang, X., Wu, Y., & Shen, L. (2012). Application of low waste technologies for design and construction: a case study in Hong Kong. Renewable and Sustainable Energy Reviews, 16(5), 2973-2979. Zhijun, F., & Nailing, Y. (2007). Putting a circular economy into practice in China. Sustainability Science, 2(1), 95-101. Zhu, D. (2000). From sustainable development to circular economy. World Environ, 3, 6-12. Zhu, Q., Geng, Y., & Lai, K. H. (2010). Circular economy practices among Chinese manufacturers varying in environmental-oriented supply chain cooperation and the performance implications. Journal of Environmental Management, 91(6), 1324-1331. Zhu, S., & Qiu, D. (2008). Eco-Efficiency Indicators and their Demonstration as the Circular Economy Measurement in China [J]. Resources and Environment in the Yangtze Basin, 1, 002. Zuidema, R. H. (2015). Open building as the basis for circular economy buildings. In Proceedings of the Future of Open Building Conference. ETH Zürich. Zuo, J., & Zhao, Z. Y. (2014). Green building research–current status and future agenda: A review. Renewable and sustainable energy reviews, 30, 271-281. Zuo, J., Rameezdeen, R., Hagger, M., Zhou, Z., & Ding, Z. (2017). Dust pollution control on construction sites: Awareness and self-responsibility of managers. Journal of cleaner production, 166, 312-320. Zuo, J., Read, B., Pullen, S., & Shi, Q. (2012). Achieving carbon neutrality in commercial building developments–Perceptions of the construction industry. Habitat International, 36(2), 278-286.

336

Appendices

Appendix A: Website of Lagos State Government Building Control Agency

337

Appendix B: Design Approaches for Minimising Waste

338

339

340

Source: Ajayi (2017)

341

Appendix C: Procurement Approaches for Minimising Waste

342

Source: Ajayi (2017)

343

Appendix D: Construction approaches to minimising waste

344

345

346

Source: Ajayi (2017)

347

Appendix E: Email Correspondence from Corporate Affairs Commission

348

Appendix F: Survey Questionnaire DEVELOPING A CIRCULAR ECONOMY-BASED CONSTRUCTION WASTE MANAGEMENT FRAMEWORK FOR THE NIGERIAN CONSTRUCTION INDUSTRY This questionnaire examines current waste minimisation and management practices on construction project sites to proffer possible solutions to effective and efficient waste management on and off sites. Please tick appropriate answers based on your experience with your present employer. SECTION A: GENERAL INFORMATION 1. What best describes your position in this company?  Chief Executive Officer  Manager  Project Manager  Architect  Engineer  Contract/Quality Manager  Quantity Surveyor  Builder  Technician  Other, Please specify……………………………………………………………

2. Highest level of education?  ND  HND  PGD  Bachelor  Masters  PhD

3. Your years of experience in the construction industry?  1-5  6 – 10  11 – 15 16 – 20  above 21

4. Company ownership status? Privately owned Partnership Government-owned Public Limited Company

5. How old is your company?  1 – 5yrs  6 – 10yrs  11 – 15yrs  16 – 20yrs  above 21yrs

6. Company’s main construction activity?  New build  maintenance/repair  Renovation  Demolition/Deconstruction  Other, please specify…………………………………………………………..

7. What best describes the annual turnover of your company?  Up to N50million  N51million – N100million  N101million and above

8. Please provide the percentage of each of the following types of construction that your company would normally undertake (e.g. 10%, 25%, 70% etc. Total = 100%)

Residential Commercial Industrial Educational Agricultural Religious Recreation/ Maintenance/ Entertainment Refurbishment

9. Does your company have a waste management policy?  Yes  No  I don’t know

10. Estimate the average loss due to material waste as a percentage of the total cost of materials (Please tick only one option).  < 10%  10 to < 20%  20 to

349

< 30%  30 to < 40%  40% to < 50%  > 50% Please specify……………………………………. SECTION B: AWARENESS, ATTITUDE AND PERCEPTION 11. Rank the type of material waste produced in your main type of construction (1 – most to 6 – least) Types of material waste Rank Concrete, ceramics and stone Timber and timber products Glass Metal products (e.g. reinforcement bars, aluminium, steel etc.) Plastic and rubber Bricks and blocks Other – please specify:

12. Thinking of your main type of construction, rank the causes of material waste (1- most to 8 – least) Causes of material waste Rank Design variations Contractual variations Procurement Transportation / material handling and storage On-site management and planning Site operation activities Weather damage and effects Vandalism / theft Other – please specify:

13. Based on your ranking of the causes of material waste (above), please rank the 3 main people/entities who should be responsible for material waste minimisation.

Stakeholders Rank Architects Builders Clients Contractors/Developers Engineers Government Labourers Material suppliers Project Managers/Site Managers Sub-contractors Quantity Surveyors Other – Please specify:

350

14. Please rate your level of agreement with the following items.

Awareness, Attitudes and Perceptions Level of agreement 14.1 Awareness Strongly Disagre Neutral Agree Strongly disagre e agree e 14.1.1 Construction waste is harmful to human health and the environment 14.1.2 An organized construction waste sorting method will increase materials re-use 14.1.3 Recycling rate of construction waste is low 14.1.4 Reusable containers / bags reduce materials packaging waste 14.1.5 Waste of materials is avoidable 14.2 Attitude Strongly Disagre Neutral Agree Strongly disagre e agree e 14.2.1 I interact closely with my construction team to avoid material waste. 14.2.2 I advise clients where there is potential for waste reduction 14.2.3 I see construction waste minimisation as important as other functions of construction management 14.2.4 I find it hard to change existing work practices 14.2.5 I think cost of waste does not have much effect on the project 14.3 Perceptions Strongly Disagre Neutral Agree Strongly disagre e agree e 14.3.1 Waste generation is often the result of bad planning and management 14.3.2 Through waste management, construction site employees can contribute significantly to protecting the environment 14.3.3 The benefits of recycling construction waste are not worth the time required to sort waste materials for recycling 14.3.4 The value of recycled or re-used construction materials is minimal 14.3.5 Waste is an inevitable by-product on construction projects

15. How important does your company view the following waste management factors? Level of importance Waste management Not Less Neutral Important Very factors important important important 15.1 Training and education of project team members 15.2 Sustainable construction

351

15.3 Eco design/Design for the Environment 15.4 Green procurement/Sustainable procurement 15.5 Communication with other firms 15.6 Government policies, laws and legislation

16. How important do you perceive the following project goals to your company? Level of importance Project goals Not Less Neutral Important Very important important important 16.1 Time 16.2 Cost 16.3 Quality 16.4 Environment 16.5 Safety

17. Thinking of your main type of material waste, tick the main disposal method (tick only one option).  Open dumping  Recycling  Landfilling  Composting  Incineration  Reuse as backfill  Onsite dig and bury  Burning  Other (Please specify)…………………………………………………………

SECTION C: WASTE MANAGEMENT APPROACHES C1 Eco design/Design for the environment (DfE)

18. Please rate your level of agreement with the following causes of material waste at the design phase. Material waste at design phase Strongly Disagree Neutral Agree Strongly disagree agree 18.1 Lack of attention/knowledge about dimensional co-ordination of materials 18.2 Design changes while construction is in progress 18.3 Designer’s inexperience in method and sequence of construction 18.4 Designer’s unfamiliarity with alternative products 18.5 Complexity of drawing details 18.6 Errors in contract documents 18.7 Unclear/unsuitable specifications 18.8 Poor coordination and communication between design team members 18.9 Selection of low-quality products 18.10 Other – Please specify:

352

19. Identify your company’s design approaches to material waste minimisation.

Eco Design / Design for the Environment Level of usage 19.1 Design for reuse and recovery: designing for use of Never Used in Used in used in recycled materials or materials salvaged from other sites been Rarely some most all used used projects projects projects 19.1.1 Reuse existing buildings and landscapes 19.1.2 Reuse building components and materials 19.1.3 Use recycled building components and materials 19.1.4 Design with less variety of materials 19.2 Design for off-site construction: designing for use of Never Used in Used in used in prefabrication to reduce the number of trades and activities been Rarely some most all on site used used projects projects projects 19.2.1 Use off-site prefabricated pods i.e. kitchen cabinets, railings, doors etc. 19.2.2 Use off-site prefabricated and pre-cut building elements 19.2.3 Use off-site prefabrication of structural elements 19.2.4 Use modular construction 19.3 Design for materials optimisation: designing to minimise Never Used in Used in used in excavation, or standardise materials or component choices been Rarely some most all used used projects projects projects 19.3.1 Simplify the building form, layout and elements 19.3.2 Uniform design, e.g. room sizes, floor to ceiling heights and material sizes 19.3.3 Use local materials 19.3.4 Specify recycled content in design 19.3.5 Consider maintenance, service and replacement requirements of each component 19.4 Design for waste efficient procurement: designing to ensure early consultation with contractors on how to reduce Never Used in Used in used in waste in the supply chain, or tighter specification of work been Rarely some most all procedures such as allowing use of off-cuts used used projects projects projects 19.4.1 Use contractual documents to set waste performance requirements 19.4.2 Specify responsibly sourced materials 19.4.3 Prepare a Site Waste Management Plan 19.4.4 Consider materials logistics e.g. Just-in-time deliveries 19.4.5 Reduce packaging requirements in materials procurement 19.4.6 Consider impact of material on the environment 19.4.7 Collaborate with others in the supply chain 19.5 Design for deconstruction and flexibility: designing to allow for recovery of materials during building Never Used in Used in used in refurbishments, such as use of easily disassembled been Rarely some most all structures in building projects used used projects projects projects 19.5.1 Use precast concrete and / or steel frames 19.5.2 Use lime mortar and / or mortar-less masonry to facilitate reuse

353

19.5.3 Use flexible construction methods to enable change of use 19.5.4 Consider reuse potential once design life is complete

C2 Green Procurement

20. Please rate your level of agreement with the following causes of material waste at the procurement phase. Procurement phase Strongly Disagree Neutral Agree Strongly disagree agree 20.1 Ordering errors (too much or too little) 20.2 Lack of possibilities to order small quantities 20.3 Non-compliance with specification 20.4 Supplier’s errors e.g. incorrect thickness supplied 20.5 Substandard materials 20.6 Bulk delivery (storage of materials delivered in bulk) 20.7 Manufacturing defects/Defective materials 20.8 Other – Please specify:

21. Identify your company’s procurement approaches to material waste minimisation.

Green procurement / Sustainable procurement Level of usage Never Used in Used in used in been Rarely some most all used used projects projects projects 21.1 Choose materials with low environmental impact 21.2 Purchase multifunctional materials 21.3 Purchase durable materials 21.4 Purchase from local suppliers 21.5 Examine the need for the material 21.6 Consider alternatives, such as reusing, refurbishing or reconditioning existing products or their components to extend their life 21.7 Choose materials with the least environmental and/or social impact 21.8 Consider the environmental management practices of suppliers / manufacturers 21.9 Verify the social responsibility and ethical behaviour of manufacturers and suppliers of the product 21.10 Reduce the hazardous material content in purchases, including toxicity 21.11 Consider the end-of-life options, including the reuse, repair, recycling and disposal options 21.12 Ask suppliers to commit to waste reduction goals 21.13 Adopt just-in-time (JIT) delivery of materials 21.14 Other – Please, specify

354

C3 Sustainable Construction 22. Please rate your level of agreement with the following causes of material waste at the construction phase. Construction phase Strongly Disagree Neutral Agree Strongly disagree agree 22.1 Errors by tradespersons or labourers 22.2 Accidents 22.3 Use of incorrect material, thus requiring replacement 22.4 Equipment malfunction 22.5 Required quantity differs from quantity needed 22.6 Quality of supervision 22.7 Lack of on-site waste management plans 22.8 Improper site layout 22.9 On-site material controls 22.10 Poor material storage 22.11 Off-cuts from materials 22.12 Ineffective communication 22.13 Waste from application processes (e.g. plastering) 22.14 Unconcerned attitude of project team and labourers 22.15 Other – Please specify:

23. Identify your company’s construction approaches to material waste minimisation.

Sustainable construction Level of usage Never Used in Used in used in been Rarely some most all used used projects projects projects 23.1 Conduct comprehensive feasibility studies 23.2 Set targets for allowable waste 23.3 Appoint a waste management contractor 23.4 Improved construction methods e.g. Industrialised building system 23.5 Lean construction 23.6 Effective teamwork among stakeholders 23.7 Make waste reduction efforts financially beneficial 23.8 Educate construction and management teams on waste reduction 23.9 Avoid excavating unnecessary soil 23.10 Use excavated soil elsewhere on the same construction site 23.11 Use no-dig or trenchless technologies 23.12 Provide space on site for the management of C&D waste

355

23.13 Identify construction activities that can reuse materials 23.14 Stock control measures (e.g. stock taking) 23.15 Adopt building information modelling (BIM) and ICT tools 23.16 Other – Please, specify

C4 The 3Rs’ – Reduce, Reuse and Recycle 24. Identify your company’s 3Rs’ (reduce, reuse & recycle) approaches to material waste minimisation.

3Rs – Reduce, Reuse and Recycle Level of usage Never Used in Used in used in been Rarely some most all used used projects projects projects 24.1 On-site sorting and segregation of material wastes 24.2 Use systems that favour segregation into their elements at the end of their useful life 24.3 Use skips for segregation on specific materials 24.4 Evaluate if salvage of used-products is possible 24.5 Use reusable formwork and scaffolding 24.6 Re-use of materials on-site 24.7 Re-use of materials on different site 24.8 Use recycled materials 24.9 Send waste materials to recycling facility 24.10 Recycle waste on-site 24.11 Other – Please, specify

SECTION D: POLICY AND IMPLEMENTATION 25. Are you aware of government policies or legislation about construction waste minimisation/management?  Yes  No 26. From your experience, please rank the following waste management implementation methods in their order of priority (Please, use positions e.g. 1st, 2nd, 3rd etc.)

Implementation methods Rank 26.1 Policy and goal on construction waste management 26.2 Legislation on construction waste management 26.3 Cooperation and communication among stakeholders in the construction industry 26.4 Promotion of research and technology 26.5 International cooperation among construction industries 26.6 Education and training of construction professionals 26.7 Other - Please specify:

27. Please, indicate the level of importance of the following policies/measures in managing construction waste.

356

Policies/Measures Level of importance Not at Less Neutral Important Very all important important 27.1 Construction waste disposal charging scheme (to encourage the construction workforce to consider 3R principles before disposal) 27.2 Stepwise incentive system (an award given to those producing low levels of waste) 27.3 Extended Producer Responsibility (producers’ responsibilities across the life cycle of their products especially when the products are discarded as waste) 27.4 Pay-as-you-throw (PAYT) / landfill charging scheme (requires construction workforce to pay for the amount of waste that they produce) 27.5 Landfill ban (outright ban on the disposal of reusable/recyclable construction materials) 27.7 Contractor’s willingness to pay (WTP) for waste management 27.8 Financial incentives for operatives (labourers) to sort and segregate waste 27.9 Appoint a waste manager (new position where someone is appointed to coordinate waste management procedures on site) 27.10 Use waste prediction tools (to generate waste forecasts) 27.11 Site waste management plan (SWMP) 27.12 Other – Please, specify

28. Please, indicate your level of agreement with the following. Level of agreement Strongl Disagree Neutral Agree Strongl Factors y y agree disagre e 28.1 Our current design approaches meet the sustainability agenda on eco design/design for the environment of our organisation 28.2 Our current procurement method(s) meet the sustainability agenda on green procurement of our organisation 28.3 Our current construction method(s) meet the sustainability agenda on sustainable construction of our company 28.4 Our current construction waste minimisation and management approaches are efficient and effective 28.5 Our company is willing to adopt a new construction waste minimisation/ management method if proven efficient and effective

357

**End of Questionnaire** Thank you for taking time to complete this questionnaire.

358

Appendix G: Cover Letter for Online Survey Request Subject: Invitation to take a research survey on construction waste management Date Dear Participant,

My name is Olabode Emmanuel Ogunmakinde and I am a PhD student at the University of Newcastle (UoN), Australia. I am developing a circular economy-based construction waste management framework for Nigeria. Because you are an Architect / Engineer / Project Manager / Manager / Chief Executive Officer /Quantity Surveyor / Technician / Contract or Quality Control Manager / Builder working at a construction firm in Lagos State, Nigeria, I am inviting you to participate in this research study by completing a survey.

The questionnaire will require approximately 20 – 30 minutes to complete. There are no right or wrong answers. We are seeking your opinion on various aspects of construction waste. There is no known risk in completing the survey. If you choose to participate in this project, please answer all questions as frankly as possible. Participation is voluntary and you may refuse to participate at any time. Please see the attached information sheet for full details about your participation and this survey.

Thank you for taking time to assist me in my research. The data collected will provide useful information regarding construction waste minimisation and management on construction projects in Nigeria. If you would like a summary copy of this study please email [email protected]. Completion and return of the questionnaire will indicate your willingness to participate in this study. If you require additional information or have questions, please refer to the information sheet for the contact details.

Click here to participate in the survey.

Thank you for considering my request. I sincerely hope you will assist me and participate in this survey.

Sincerely, Olabode Emmanuel Ogunmakinde T: +61 4 1581 5561; +2348032302068 E: [email protected]

Supervisors A/Prof. William David Sher T: +61 2 4921 5792 E: [email protected]

Dr Kim Maund T: +61 2 4921 6729 E: [email protected]

359

Appendix H: Reminder Letter for Online Survey Request Subject: REMINDER: Invitation to take a research survey on construction waste management Date Dear Sir/Madam, Recently you received an e-mail message asking you to assist us in assessing construction waste management by filling out a web-based survey. If you have filled out the survey, thank you! If you have not had a chance to take the survey yet, I would appreciate your reading the message below and completing the survey. This survey should take no more than 20 to 30 minutes to complete. This message has gone to everyone in the selected sample population. Since no personal data is retained with the surveys for reasons of confidentiality, we are unable to identify whether or not you have already completed the survey. To complete the survey, please click on the web address below. If that does not work, please copy and paste the entire web address into the address field of your browser. * https://www.surveymonkey.com/r/DFDS5W9

Thank you for your time!

Kind regards, Olabode Emmanuel Ogunmakinde PhD Candidate, School of Architecture and Built Environment, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia. Tel: +61415815561 Alt. Email: [email protected] Profile: http://www.newcastle.edu.au/profile/olabode-ogunmakinde-uon

360

Appendix I: Interview Guide DEVELOPING A CIRCULAR ECONOMY APPROACH FOR MANAGING CONSTRUCTION AND DEMOLITION WASTE IN THE NIGERIAN CONSTRUCTION INDUSTRY INTERVIEW GUIDE Introduction: Self introduction, name and general affiliation Purpose of Interview We are aware that waste generated on construction sites poses serious threats to the environment and sustainable construction. Some methods have been applied to manage construction waste but their effectiveness remains unknown. We are interested in knowing your views about any waste management method(s) you have adopted particularly at the design, procurement and construction phases. If it is okay with you, I will be recording our conversation. The purpose is to get all the details and at the same time be able to carry on an attentive conversation with you. I assure you that all your comments will remain confidential. If you agree to this interview and the recording, please sign this consent form.

Questions Demographic data/ Background Information 1. Could you please introduce yourself, your professional background and industry experience? 2. Could you please tell me precisely your role on this project? 3. Does your company have a plan or policy on managing construction waste? (Probes - Can you provide an overview of that policy? What are the key things in that policy to support construction waste management in an efficient manner?) Causes and effects of material wastage 4. From your perspective, what are the causes of material wastage and their effects on this project? 5. Based on the causes of waste you have enumerated, who do you think should be responsible for minimising such wastes? 6. How do you dispose material waste generated on this project? Awareness, Attitudes and Perceptions 7. What does material waste management mean to you? 8. How do you decide what to do with material waste? 9. Considering waste management on this project, why do you think it is important to minimise material waste? 10. If your company were to organise training on construction management, what will be the focus of such training? Material Waste Minimisation/Management Strategy 11. In terms of material waste minimisation, how would you describe the design approaches adopted for this project?

361

12. In terms of material waste minimisation, how would you describe the procurement approaches adopted for this project? 13. In terms of material waste minimisation, how would you describe the construction method(s) adopted for this project? 14. In terms of material waste management, how would you describe the reuse and recycling approaches adopted for this project?

Implementation/Managerial Strategies 15. Are you aware of government policies or legislation about waste management on construction sites? 16. Drawing from your experience, what strategies do you think will aid effective material waste management on local construction sites? 17. How best can we implement material waste management in the Nigerian construction industry? **End of Interview** Thank you!

362

Appendix J1: Information Statement for Organisations (Interviews)

Associate Professor William D. Sher School of Architecture and Built Environment Faculty of Engineering and Built Environment University of Newcastle Callahan, NSW 2308] +61 2 49215792 [email protected]

Information Statement for the Research Project Developing a Circular Economy Approach for Managing Construction and Demolition Wastes in the Nigerian Construction Industry (Version number 2, dated 06 September 2016) Research Team: Principal Investigator: Principal Investigator: Student Investigator: Associate Professor William D. Dr Kim Maund Olabode E. Univ ersity of Newcastle Lecturer PhD candidate University of Newcastle University of Newcastle

University Drive, Callaghan NSW 2308, Australia.

15 September 2016

Dear Mr/Mrs……………………………………………………

Your organisation is invited to participate in the research project identified above which is being conducted by Associate Professor William D. Sher, Dr Kim Maund and Olabode E. Ogunmakinde from the School of Architecture and Built Environment at the University of Newcastle, Australia. The research is part of Olabode E. Ogunmakinde’s PhD studies at the University of Newcastle.

We are exploring the status quo and management of construction and demolition (C&D) waste in Nigeria with a view to developing a circular economy approach for managing C&D wastes. Your organisation is being invited to participate as a construction firm operating in Nigeria. This sheet contains information about the research.

363

Nigeria, C&D wastes contribute to environmental degradation with little or no active waste management strategies in place. Unsurprisingly, a large portion of this waste ends up as landfill, resulting in environmental hazards, and inefficient resource and energy use. To mitigate these outcomes, there is need for effective and efficient waste management strategies. The circular economy concept has the potential to minimise waste, reduce pressure on resource consumption and promote efficient energy use. Although, principles of the circular economy such as reuse and recycling have been identified as effective waste minimisation strategies, very few construction firms in Nigeria adopts them.

The aim of the research is to develop a circular economy based waste management framework for improving the management of C&D waste in the Nigerian construction industry. To do this, the status quo of C&D wastes in Nigeria needs to be explored to inform the development of a tailor-made circular economy waste minimisation strategy.

Who can participate in the research? Participants in the research will be Architects, Engineers, Quantity Surveyors, Builders, Project Managers/Site Managers, Contractors, Sub-contractors, Foremen and labourers working on building construction projects in Lagos State, Nigeria.

What choice do you have? Participation in this research is entirely your choice. Only those who give their informed consent will be included in the project. Whether or not you consent to your employees participating, your decision will not disadvantage you. If you do decide for your employees to participate, you may withdraw from the project at any time without giving a reason.

What would you be asked to do? Your organisation has been identified from the construction project sign board displayed at ………………………………………………………………………………………………… ………………….... If you agree to participate, you will be asked to read the information statement, sign and return the consent form to the researchers. Your consent to conduct interviews with your employees on company’s premises will be required. Also, you will be asked to disseminate Participant Information Sheet and Participant consent form to eligible employees and allow them decide whether to participate or not. An introduction to eligible participants and other management staff on the construction site will be required. The interview will be conducted at the participant’s convenience, in a location of their choice (face to face or through telephone).

What will your employees be asked to do? Your employees will be asked to read the information statement and sign the consent form if they are willing to participate. They will be asked to participate in an interview seeking to obtain information on construction waste management practices adopted on the current construction site. They will be contacted to arrange interviews. Where possible, interviews will be conducted at the participant’s workplace and during business hours. The interview questions seek opinions – there are no right or wrong answers.

What are the risks and benefits of participating? By participating in this research your organisation will be contributing to the development of a circular economy based waste management approach for the Nigerian construction industry. It is not anticipated that participation in the research would present any appreciable risks to you. There are no identifiable direct benefits to your organisation or you as an individual.

364

However, the findings of this research could benefit the industry to better understand how C&D wastes can be managed effectively using the circular economy approach.

How will your privacy be protected? All data gathered through the Interview will be treated with the strictest confidence. All identifiable features (i.e. names of individuals, projects and email addresses) will be removed and codes will be assigned. Participants will be provided the opportunity, upon request to review, edit, or erase the recordings or transcripts of the interviews. Only the research team, except as required by law, will have access to personally identifiable data collected. All information will be stored in password protected computer files. Once the project is complete the information will be stored for a minimum of five years in the Principal Investigator’s office in a locked cabinet and then destroyed according to University of Newcastle procedures. Interview data will be transcribed by a transcribing service used by the University. The transcription service will be bound by a confidentiality agreement.

How will the information collected be used? The data will be used within a range of publications such as journals, international conferences and in the Doctoral thesis to be submitted by Olabode E. Ogunmakinde. Participants will not be identified in any reports arising from the project. The participants will be offered a summary of the results. If you would like to receive a summary of the results of the research, please register your request in the ‘Consent Form’ or by contacting Associate Professor William D. Sher on the phone number or email address below.

What do you need to do to participate? Please read this Information Statement and be sure you understand its contents before you consent to participate. If there is anything you do not understand, or you have questions, contact the researcher. Should you choose to participate in this study, please complete the attached ‘Consent Form’ and e-mail or post it to Associate Professor William D. Sher. The research team will then make contact with potential participants. Please keep this information sheet.

Further information If you would like further information please contact Associate Professor William D. Sher, Dr Kim Maund or Olabode E. Ogunmakinde on the phone number or email address below.

Thank you for considering this invitation.

Research Team: Principal Investigator: Principal Investigator: Student Investigator: A/Prof. William D. Sher Dr Kim Maund Olabode E. Ogunmakinde University of Newcastle Lecturer PhD candidate University of Newcastle University of Newcastle

365

Research Team Contact Details

Associate Professor William D. Sher University of Newcastle Telephone: +61 2 49215792 Email: [email protected]

Dr Kim Maund University of Newcastle Telephone: +61 2 49216729 Email: [email protected]

Olabode E. Ogunmakinde University of Newcastle Telephone: +61415815561 Email: [email protected]

Complaints about this research This project has been approved by the University’s Human Research Ethics Committee (H- 2016-0295).

Should you have concerns about your rights as a participant in this research, or you have a complaint about the manner in which the research is conducted, it may be given to the researcher, or, if an independent person is preferred, to the Human Research Ethics Officer, Research Office, The Chancellery, The University of Newcastle, University Drive, Callaghan NSW 2308, Australia, telephone +61 2 49216333, email [email protected].

366

Appendix J2: Information Statement for Interviewees

Information Statement for the Research Project Developing a Circular Economy Approach for Managing Construction and Demolition Wastes in the Nigerian Construction Industry (Version number 2, dated 06 September 2016) Research Team: Principal Investigator: Principal Investigator: Student Investigator: Associate Professor William D. Sher Dr Kim Maund Olabode E. Ogunmakinde University of Newcastle Lecturer PhD candidate University of Newcastle University of Newcastle

You are invited to participate in the research project identified above which is being conducted by Associate Professor William D. Sher, Kim Maund and Olabode E. Ogunmakinde (PhD candidate) from the School of Architecture and Built Environment at the University of Newcastle, Australia. The research is part of Olabode E. Ogunmakinde’s PhD studies at the University of Newcastle.

You are being invited to participate in the research as a construction and management team member working on a construction site in Nigeria. This sheet contains information about the research.

Why is the research being done? Across developing countries particularly in Africa and Asia, infrastructure development has soared as a result of rapid urbanization. This implies more construction activities. Wastes generated from these activities are known as construction and demolition waste (C&D). In Nigeria, C&D wastes contribute to environmental degradation with little or no active waste management strategies in place. Unsurprisingly, a large portion of this waste ends up as landfill, resulting in environmental hazards, and inefficient resource and energy use. To mitigate these outcomes, there is need for effective and efficient waste management strategies. The circular economy concept has the potential to minimise waste, reduce pressure on resource consumption and promote efficient energy use. Although, principles of the circular economy such as reuse and recycling have been identified as effective waste minimisation strategies, very few construction firms in Nigeria adopts them.

367

What would you be asked to do? The interview will be conducted at your convenience, in a location of your choice (face to face or through telephone). Where possible interviews will be conducted at your workplace and during business hours. The interview questions seek your opinion – there are no right or wrong answers. Once you have provided your consent to participate, Olabode E. Ogunmakinde will be the researcher that will contact you to organise a date and time for the interview. He will also be the person conducting the interviews.

How much time will it take? The interview should take about one (1) hour to complete. You will only be required to participate in one interview.

What are the risks and benefits of participating? By participating in this research you will be contributing to the development of a circular economy based waste management approach for the Nigerian construction industry. It is not anticipated that participation in the research would present any appreciable risks to you. There are no identifiable direct benefits to individual participants. However, the findings of this research could benefit the industry to better understand how C&D wastes can be managed effectively using the circular economy approach.

How will your privacy be protected? All data gathered through the Interview will be treated with the strictest confidence. All identifiable features (i.e. names of individuals, projects and email addresses) will be removed and codes will be assigned. You will be provided the opportunity, upon request to review, edit, or erase the recordings or transcripts of the interviews. Only the research team, except as required by law, will have access to personally identifiable data collected. All information will be stored in password protected computer files. Once the project is complete the information will be stored for a minimum of five years in the Principal Investigator’s office in a locked cabinet and then destroyed according to University of Newcastle procedures. Interview data will be transcribed by a transcribing service used by the University. The transcription service will be bound by a confidentiality agreement.

What do you need to do to participate? Please read this Information Statement and be sure you understand its contents before you consent to participate. If there is anything you do not understand, or you have questions, contact the researcher. Should you choose to participate in this study, please complete the attached ‘Consent Form’ and e-mail or post it to Associate Professor William D. Sher. The research team will then contact you to arrange a time convenient to you for the interview. Please keep this information sheet.

Further information If you would like further information please contact Associate Professor William D. Sher, Kim Maund or Olabode E. Ogunmakinde on the phone number or email address below.

Thank you for considering this invitation.

368

Research Team: Principal Investigator: Principal Investigator: Student Investigator: Associate Professor William D. Sher Dr Kim Maund Olabode E. Ogunmakinde University of Newcastle Lecturer PhD candidate University of Newcastle University of Newcastle

Research Team Contact Details

Associate Professor William D. Sher University of Newcastle Telephone: +61 2 49215792 Email: [email protected]

Dr Kim Maund University of Newcastle Telephone: +61 2 49216729 Email: [email protected]

Olabode E. Ogunmakinde University of Newcastle Telephone: +61415815561 Email: [email protected]

Complaints about this research This project has been approved by the University’s Human Research Ethics Committee (H-2016-0295).

369

Appendix K1: Consent Form for Organisations

370

Appendix K2: Consent Form for Interviewees

371

Appendix L: Information Statement for Organisations (Questionnaire)

Information Statement for the Research Project Developing a Circular Economy Approach for Managing Construction and Demolition Wastes in the Nigerian Construction Industry (Version number 2, dated 06 September 2016) Research Team: Principal Investigator: Principal Investigator: Student Investigator: Associate Professor William D. Dr Kim Maund Olabode Ogunmakinde Univ ersity of Newcastle Lecturer PhD candidate University of Newcastle University of Newcastle

University Drive, Callaghan NSW 2308, Australia.

15 September 2016

Dear Mr/Mrs……………………………………………………

Why is the research being conducted? Across developing countries particularly in Africa and Asia, infrastructure development has soared as a result of rapid urbanization. This implies more construction activities. Wastes generated from these activities are known as construction and demolition waste (C&D). In Nigeria, C&D wastes contribute to environmental degradation with little or no active waste

372 management strategies in place. Unsurprisingly, a large portion of this waste ends up as landfill, resulting in environmental hazards, and inefficient resource and energy use. To mitigate these outcomes, there is need for effective and efficient waste management strategies. The circular economy concept has the potential to minimise waste, reduce pressure on resource consumption and promote efficient energy use. Although, principles of the circular economy such as reuse and recycling have been identified as effective waste minimisation strategies, very few construction firms in Nigeria adopts them.

Who can participate in the research? Representatives of building construction organisations including Chief Executive Officers, General Managers, Architects, Engineers, Quantity Surveyors, Builders, Project Managers, Contract/Quality Managers and Technicians working at building construction firms in Lagos State, Nigeria.

What choice do you have? Participation in this research is entirely your choice. Only those who give their informed consent will be included in the project. Whether or not you consent to participate, your decision will not disadvantage you. If you do decide to participate, you may withdraw from the project at any time without giving a reason.

What would you be asked to do? “If you are not one of the following: Chief Executive Officer, General Manager, Architect, Engineer, Quantity Surveyor, Builder, Project Manager, Contract/Quality Manager, or Technician, please pass these documents to a colleague who qualifies. As a representative of your organisation, if you agree to participate, you will be asked to read the information statement, complete a survey questionnaire and return it to the researchers. If you do not agree to participate, you do not need to do anything further.

How long will it take? The questionnaire will take approximately 30 – 45 minutes to complete.

What are the risks and benefits of participating? By participating in this research your organisation will be contributing to the development of a circular economy-based waste management approach for the Nigerian construction industry. It is not anticipated that participation in the research would present any appreciable risks to you. There are no identifiable direct benefits to your organisation or you as an individual. However, the findings of this research could benefit the industry to better understand how C&D wastes can be managed effectively using the circular economy approach.

How will your privacy be protected? All data gathered through the survey will be treated with the strictest confidence. All identifiable features (i.e. names of individuals, projects and email addresses) will be removed and codes will be assigned. Only the research team, except as required by law, will have access to personally identifiable data collected. All information will be stored in password protected computer files. Once the project is complete the information will be stored for a minimum of

373

five years in the Principal Investigator’s office in a locked cabinet and then destroyed according to University of Newcastle procedures.

How will the information collected be used? The data will be used within a range of publications such as journals, international conferences and in the Doctoral thesis to be submitted by Olabode E. Ogunmakinde. Participants will not be identified in any reports arising from the project. The participants will be offered a summary of the results. If you would like to receive a summary of the results of the research, please register your request by contacting Associate Professor William D. Sher on the phone number or email address below.

What do you need to do to participate? Please read this Information Statement and be sure you understand its contents before you consent to participate. If there is anything you do not understand, or you have questions, contact the researcher. Should you choose to participate in this study, please complete and return the ‘Survey Questionnaire’ sent to your email to: [email protected] Please keep this information sheet.

Further information If you would like further information please contact Associate Professor William D. Sher, Dr Kim Maund or Olabode E. Ogunmakinde on the phone number or email address below.

Thank you for considering this invitation.

Research Team Contact Details

Associate Professor William D. Sher University of Newcastle Telephone: +61 2 49215792 Email: [email protected]

Dr Kim Maund University of Newcastle Telephone: +61 2 49216729 Email: [email protected]

Olabode E. Ogunmakinde University of Newcastle Telephone: +61415815561 Email: [email protected]

374

Complaints about this research This project has been approved by the University’s Human Research Ethics Committee (H- 2016-0295).

375

Appendix M: Human Research Ethics Approval

376

377

378

Appendix N: Overall causes of material waste

Overall causes SD D N A SA W RII Rank Quality of supervision 0 2 19 126 94 1035 0.859 1 Design changes 4 4 14 127 92 1022 0.844 2 Unconcerned attitude of project 0 8 20 137 78 1014 0.835 3 team and labourers Lack of on-site waste management 2 8 20 136 77 1007 0.828 4 plans Off-cuts from materials 2 7 27 136 71 996 0.819 5 Waste from application processes 1 11 19 151 57 969 0.811 6 (e.g. plastering) Errors by tradespersons or 2 13 19 146 63 984 0.809 7 labourers Poor material storage 1 5 35 135 64 976 0.807 8 Poor coordination and communication between design 4 15 19 147 57 964 0.797 9 team members On-site material controls 0 9 33 156 44 961 0.794 10 Ineffective communication 1 16 29 149 48 956 0.786 11 Substandard materials 4 23 34 116 65 941 0.777 12 Required quantity differs from 5 13 39 133 52 940 0.776 13 quantity needed Use of incorrect material, thus 1 23 25 149 43 933 0.774 14 requiring replacement Unclear/unsuitable specification 2 20 37 134 50 939 0.773 15 Manufacturing defects or defective 1 16 35 153 37 935 0.773 16 materials Lack of attention/knowledge about dimensional coordination of 6 20 24 149 43 929 0.768 17 material Designer’s inexperience in method 4 26 32 130 50 922 0.762 18 and sequence of construction Selection of low-quality products 2 28 39 119 54 921 0.761 19 Designer’s unfamiliarity with 3 20 38 145 36 917 0.757 20 alternative products Non-compliance with specification 4 26 37 135 40 907 0.749 21 Equipment malfunction 3 16 51 146 27 907 0.746 22 Improper site layout 3 28 43 133 36 900 0.741 23 Ordering errors (too much or too 5 26 43 130 38 896 0.740 24 little) Accidents 1 17 65 136 22 884 0.734 25 Supplier’s errors 5 35 38 122 41 882 0.732 26 Bulk delivery (storage of materials 5 32 41 136 28 876 0.724 27 delivered in bulk) Lack of opportunities to order 6 43 53 120 21 836 0.688 28 small quantities Complexity of drawing details 10 52 55 99 26 805 0.665 29 Errors in contract documents 10 59 43 103 27 804 0.664 30 379

Appendix O: Correlation Matrix of Design Approaches

DA1 DA1 DA2 DA3 DA4 DA5 DA6 DA7 DA8 DA9 DA10 DA11 DA12 DA13 DA14 DA15 DA16 DA17 DA18 DA19 DA20 DA21 DA22 DA23 DA24

Correlation 1.000 Coefficient DA1 p-value Correlation .518** 1.000 Coefficient DA2 p-value 0.000 Correlation .474** .532** 1.000 Coefficient DA3 p-value 0.000 0.000 Correlation .385** .253** .318** 1.000 Coefficient DA4 p-value 0.000 0.000 0.000 Correlation .163* 0.092 .176** .391** 1.000 Coefficient DA5

p-value 0.012 0.155 0.006 0.000 Correlation .254** .170** .240** .237** .455** 1.000 Coefficient DA6 p-value 0.000 0.008 0.000 0.000 0.000

Spearman's rho Spearman's Correlation .271** .245** .324** .251** .259** .501** 1.000 Coefficient DA7 p-value 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .302** .207** .266** .302** .279** .375** .519** 1.000 Coefficient DA8 p-value 0.000 0.001 0.000 0.000 0.000 0.000 0.000 Correlation .302** .211** .257** .251** 0.113 0.125 .133* .245** 1.000 Coefficient DA9 p-value 0.000 0.001 0.000 0.000 0.082 0.053 0.038 0.000 Correlation .381** .221** .207** .308** .238** .226** .216** .309** .420** 1.000 Coefficient DA10 p-value 0.000 0.001 0.001 0.000 0.000 0.000 0.001 0.000 0.000 Correlation .237** .259** .269** .242** 0.032 .187** .181** .166* .373** .261** 1.000 Coefficient DA11 p-value 0.000 0.000 0.000 0.000 0.628 0.004 0.005 0.010 0.000 0.000

380

Correlation .318** .214** .357** .189** 0.105 .220** .315** .437** .221** .266** .244** 1.000 Coefficient DA12 p-value 0.000 0.001 0.000 0.003 0.107 0.001 0.000 0.000 0.001 0.000 0.000 Correlation .345** .202** .136* .203** .145* .285** .212** .268** .391** .377** .266** .285** 1.000 Coefficient DA13 p-value 0.000 0.002 0.034 0.001 0.025 0.000 0.001 0.000 0.000 0.000 0.000 0.000 Correlation .310** .138* .224** .167** .175** .273** .323** .372** .280** .234** .290** .493** .344** 1.000 Coefficient DA14 p-value 0.000 0.032 0.000 0.010 0.007 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .296** 0.069 .186** .144* .128* .207** .161* .282** .238** .262** .346** .441** .385** .555** 1.000 Coefficient DA15 p-value 0.000 0.286 0.004 0.026 0.049 0.001 0.012 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .357** .222** .347** .136* .195** .295** .362** .342** .190** .261** .228** .491** .346** .609** .478** 1.000 Coefficient DA16 p-value) 0.000 0.001 0.000 0.035 0.003 0.000 0.000 0.000 0.003 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .241** .129* .197** 0.100 0.090 .180** .127* .149* .194** .197** .251** .229** .395** .394** .422** .503** 1.000 Coefficient DA17 p-value 0.000 0.045 0.002 0.122 0.168 0.005 0.050 0.022 0.003 0.002 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .238** .148* .257** .157* 0.109 .252** .311** .310** 0.098 .285** .175** .375** .264** .425** .429** .475** .492** 1.000 Coefficient DA18 p-value 0.000 0.021 0.000 0.014 0.091 0.000 0.000 0.000 0.127 0.000 0.007 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .243** .157* .181** 0.046 0.039 .246** .312** .279** .239** .225** .275** .342** .400** .468** .472** .558** .498** .468** 1.000 Coefficient DA19 p-value 0.000 0.015 0.005 0.475 0.545 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .319** .198** .224** .186** 0.088 .230** .230** .271** .289** .323** .343** .380** .424** .405** .464** .525** .579** .495** .603** 1.000 Coefficient DA20 p-value 0.000 0.002 0.000 0.004 0.173 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .225** 0.117 .223** .172** .209** .290** .399** .450** .187** .233** .164* .368** .251** .404** .285** .377** .303** .307** .316** .327** 1.000 Coefficient DA21 p-value 0.000 0.071 0.001 0.008 0.001 0.000 0.000 0.000 0.004 0.000 0.011 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .293** .301** .414** .239** 0.101 .309** .418** .437** .241** .162* .311** .437** .306** .393** .317** .375** .249** .328** .312** .311** .564** 1.000 Coefficient DA22 p-value 0.000 0.000 0.000 0.000 0.117 0.000 0.000 0.000 0.000 0.012 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Correlation .237** .164* .239** .217** .173** .377** .309** .326** .312** .253** .233** .403** .394** .418** .431** .470** .391** .386** .468** .440** .468** .500** 1.000 Coefficient DA23 p-value 0.000 0.011 0.000 0.001 0.007 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Correlation DA24 .336** .199** .259** .142* .133* .379** .296** .394** .266** .279** .283** .510** .404** .488** .420** .506** .348** .343** .443** .463** .405** .518** .662** 1.000 Coefficient

381

p-value 0.000 0.002 0.000 0.028 0.040 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

**. Correlation is significant at the 0.01 level (2-tailed).

*. Correlation is significant at the 0.05 level (2-tailed).

382

Appendix O1: KMO and Bartlett's Test for Design Approaches

Kaiser-Meyer-Olkin Measure of Sampling Adequacy. .902 Bartlett's Test of Sphericity Approx. Chi-Square 2388.719 df 276 Sig. .000

Appendix O2: Communalities of Design Approaches

Code Design Approaches Initial Extraction DA1 Reuse existing buildings and landscapes 1.000 .614 DA2 Reuse building components and demolition materials 1.000 .708 DA3 Use recycled building components and demolition materials 1.000 .710 DA4 Design with less variety of materials 1.000 .546 DA5 Use off-site prefabricated pods i.e. kitchen cabinets, railings, doors etc. 1.000 .651 DA6 Use off-site prefabricated and pre-cut building elements 1.000 .575 DA7 Use off-site prefabrication of structural elements 1.000 .624 DA8 Use modular construction 1.000 .561 DA9 Simplify the building form, layout and elements 1.000 .672 DA10 Uniform design, e.g. room sizes, floor to ceiling heights and material sizes 1.000 .559 DA11 Use local materials 1.000 .482 DA12 Specify recycled content in design 1.000 .489 DA13 Consider maintenance, service and replacement requirements of each 1.000 .568 component DA14 Use contractual documents to set waste performance requirements 1.000 .548 DA15 Specify responsibly sourced materials 1.000 .545 DA16 Prepare a Site Waste Management Plan 1.000 .647 DA17 Consider materials logistics e.g. Just-in-time deliveries 1.000 .623 DA18 Reduce packaging requirements in materials procurement 1.000 .621 DA19 Consider impact of material on the environment 1.000 .622 DA20 Collaborate with others in the supply chain 1.000 .648 DA21 Use precast concrete and / or steel frames 1.000 .595 DA22 Use lime mortar and / or mortar-less masonry to facilitate reuse 1.000 .738 DA23 Use flexible construction methods to enable change of use 1.000 .653 DA24 Consider reuse potential once design life is complete 1.000 .648 Average .610 Extraction Method: Principal Component Analysis.

383

Appendix O3: Principal component Analysis

Total Variance Explained Extraction Sums of Squared Rotation Sums of Squared Initial Eigenvalues Loadings Loadings % of Cumulative % of Cumulative % of Cumulative Component Total Variance % Total Variance % Total Variance % 1 8.633 35.969 35.969 8.633 35.969 35.969 4.278 17.826 17.826 2 2.056 8.567 44.536 2.056 8.567 44.536 3.186 13.274 31.101 3 1.592 6.634 51.170 1.592 6.634 51.170 2.432 10.135 41.236 4 1.207 5.029 56.199 1.207 5.029 56.199 2.420 10.083 51.319 5 1.161 4.836 61.035 1.161 4.836 61.035 2.332 9.716 61.035 6 .894 3.726 64.761 7 .807 3.361 68.122 8 .766 3.190 71.312 9 .696 2.900 74.211 10 .634 2.640 76.852 11 .578 2.410 79.262 12 .576 2.398 81.660 13 .531 2.212 83.872 14 .518 2.160 86.031 15 .460 1.916 87.947 16 .431 1.796 89.743 17 .403 1.679 91.422 18 .370 1.542 92.964 19 .345 1.439 94.403 20 .305 1.271 95.673 21 .292 1.218 96.892 22 .271 1.127 98.019 23 .254 1.058 99.078 24 .221 .922 100.000 Extraction Method: Principal Component Analysis.

384

Appendix O4: New categorisation of variables after factor analysis

Design for reuse and recovery NBU RU USP UMP UAP W RII Rank (DFRR) Reuse building components and 22 66 105 44 5 670 0.554 1 materials Reuse existing buildings and 20 67 117 34 4 661 0.546 2 landscapes Use recycled building 39 78 90 33 3 612 0.503 3 components and materials Design for off-site construction (DFOC) Use off-site prefabricated pods 12 31 98 80 19 783 0.652 1 i.e. kitchen cabinets, railings, doors etc. Use off-site prefabricated and 10 56 100 66 10 736 0.608 2 pre-cut building elements Use off-site prefabrication of 24 66 95 50 8 681 0.560 3 structural elements Use modular construction 36 63 87 40 15 658 0.546 4 Design with less variety of 18 52 101 31 9 594 0.492 5 materials Design for materials optimisation (DFMO) Uniform design, e.g. room sizes, 5 31 89 89 28 830 0.686 1 floor to ceiling heights and material sizes Consider maintenance, service 2 44 91 77 29 816 0.672 2 and replacement requirements of each component Simplify the building form, layout 8 29 118 66 21 789 0.652 3 and elements Use local materials 7 32 122 61 19 776 0.644 4 Design for waste efficient procurement (DFWEP) Consider material logistics e.g. 8 32 87 77 37 826 0.685 1 Just-in-time deliveries Collaborate with others in the 6 41 96 59 41 817 0.672 2 supply chain Consider impact of material on 11 52 64 82 33 800 0.661 3 the environment Specify responsibly sourced 11 45 86 77 23 782 0.646 4 materials Prepare a site waste 31 59 70 48 32 711 0.593 5 management plan Reduce packaging requirements 19 70 98 46 10 687 0.565 6 in materials procurement

385

Use contractual documents to 33 79 65 49 16 662 0.547 7 set waste performance requirements Design for deconstruction and flexibility (DFDF) Use flexible construction 6 56 95 67 19 766 0.630 1 methods to enable change of use Use precast concrete and/or 15 47 116 51 11 716 0.597 2 steel frames Consider reuse potential once 21 80 79 43 19 685 0.566 3 design life is complete Use lime mortar and/or mortar- 49 87 57 38 12 606 0.498 4 less masonry to facilitate reuse Specify recycled content in 47 96 66 27 6 575 0.475 5 design

Appendix O5: New ranking of categories of design approaches

Eco Design/Design for the Environment Average RII Cronbach’s Rank Alpha Design for materials optimisation (DFMO) 0.664 0.705 1 Design for waste efficient procurement 0.624 0.877 2 (DFWEP) Design for off-site construction (DFOC) 0.572 0.751 3 Design for deconstruction and flexibility 0.553 0.827 4 (DFDF) Design for reuse and recovery (DFRR) 0.534 0.755 5

386

Appendix P: Correlation Matrix of Procurement Approaches Correlations

PA1 PA2 PA3 PA4 PA5 PA6 PA7 PA8 PA9 PA10 PA11 PA12 PA13 Correlation Coefficient 1.000 PA1 Sig. (2-tailed)

Correlation Coefficient .449** 1.000 PA2 Sig. (2-tailed) 0.000

Correlation Coefficient .333** .405** 1.000 PA3 Sig. (2-tailed) 0.000 0.000

Correlation Coefficient .210** .249** .231** 1.000 PA4 Sig. (2-tailed) 0.001 0.000 0.000

Correlation Coefficient .320** .330** .517** .362** 1.000 PA5 Sig. (2-tailed) 0.000 0.000 0.000 0.000 Correlation Coefficient .428** .359** .290** .282** .458** 1.000 PA6 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 Spearman's rho

Correlation Coefficient .634** .365** .334** .319** .409** .583** 1.000 PA7 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .523** .391** .291** .162* .381** .529** .652** 1.000 PA8 Sig. (2-tailed) 0.000 0.000 0.000 0.012 0.000 0.000 0.000

Correlation Coefficient .429** .340** .250** 0.103 .331** .480** .564** .698** 1.000 PA9 Sig. (2-tailed) 0.000 0.000 0.000 0.112 0.000 0.000 0.000 0.000

Correlation Coefficient .531** .373** .311** 0.126 .372** .490** .601** .633** .648** 1.000 PA10 Sig. (2-tailed) 0.000 0.000 0.000 0.051 0.000 0.000 0.000 0.000 0.000

387

Correlation Coefficient .503** .428** .347** .190** .423** .539** .570** .653** .609** .697** 1.000 PA11 Sig. (2-tailed) 0.000 0.000 0.000 0.003 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .430** .337** .187** 0.088 .252** .430** .451** .580** .530** .492** .571** 1.000 PA12 Sig. (2-tailed) 0.000 0.000 0.004 0.173 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .312** .261** .319** .161* .356** .370** .371** .519** .408** .378** .478** .508** 1.000 PA13 Sig. (2-tailed) 0.000 0.000 0.000 0.012 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 **. Correlation is significant at the 0.01 level (2-tailed). *. Correlation is significant at the 0.05 level (2-tailed).

388

Appendix P1: KMO and Bartlett's Test for Procurement Approaches

Kaiser-Meyer-Olkin Measure of Sampling Adequacy. .913 Bartlett's Test of Sphericity Approx. Chi-Square 1435.151 df 78 Sig. .000

Appendix P2: Communalities of procurement approaches

Code Procurement Approaches Initial Extraction PA1 Choose materials with low environmental impact 1.000 .457 PA2 Purchase multi-functional materials 1.000 .404 PA3 Purchase durable materials 1.000 .497 PA4 Purchase from local suppliers 1.000 .586 PA5 Examine the need for the material 1.000 .580 PA6 Consider alternatives, such as reusing, refurbishing or reconditioning existing 1.000 .536 products or their components to extend their life PA7 Choose materials with the least environmental and/or social impact 1.000 .640 PA8 Consider the environmental management practices of suppliers / manufacturers 1.000 .740 PA9 Verify the social responsibility and ethical behaviour of manufacturers and suppliers 1.000 .670 of the product PA10 Reduce the hazardous material content in purchases, including toxicity 1.000 .659 PA11 Consider the end-of-life options, including the reuse, repair, recycling and disposal 1.000 .683 options PA12 Ask suppliers to commit to waste reduction goals 1.000 .599 PA13 Adopt just-in-time (JIT) delivery of materials 1.000 .355 Average .569 Extraction Method: Principal Component Analysis.

389

Appendix P3: Total Variance of Procurement Approaches

Extraction Sums of Squared Rotation Sums of Squared Initial Eigenvalues Loadings Loadings % of Cumulative % of Cumulative % of Cumulative Component Total Variance % Total Variance % Total Variance % 1 6.036 46.427 46.427 6.036 46.427 46.427 4.925 37.882 37.882 2 1.368 10.525 56.953 1.368 10.525 56.953 2.479 19.071 56.953 3 .894 6.879 63.831 4 .843 6.487 70.318 5 .710 5.465 75.784 6 .577 4.436 80.220 7 .509 3.918 84.138 8 .440 3.386 87.524 9 .416 3.202 90.726 10 .394 3.029 93.755 11 .297 2.285 96.040 12 .274 2.107 98.148 13 .241 1.852 100.000 Extraction Method: Principal Component Analysis.

390

Appendix Q: Correlation Matrix of Sustainable Construction Approaches

Correlations

SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SC9 SC10 SC11 SC12 SC13 SC14 SC15 Correlation Coefficient 1.000 SC1 Sig. (2-tailed)

Correlation Coefficient .570** 1.000 SC2 Sig. (2-tailed) 0.000

Correlation Coefficient .479** .494** 1.000 SC3 Sig. (2-tailed) 0.000 0.000

Correlation Coefficient .456** .532** .570** 1.000 SC4 Sig. (2-tailed) 0.000 0.000 0.000

Correlation Coefficient .428** .491** .549** .609** 1.000 SC5 Sig. (2-tailed) 0.000 0.000 0.000 0.000

Correlation Coefficient .451** .464** .288** .514** .411** 1.000 SC6 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .352** .441** .428** .460** .439** .492** 1.000 SC7 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .452** .480** .426** .477** .409** .622** .546** 1.000 SC8 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .312** .353** 0.127 .256** .190** .476** .434** .360** 1.000

SC9 Sig. (2-tailed) 0.000 0.000 0.050 0.000 0.003 0.000 0.000 0.000

Correlation Coefficient .173** .159* .147* .196** 0.114 .294** .267** .270** .454** 1.000 SC10 Sig. (2-tailed) 0.007 0.014 0.024 0.002 0.079 0.000 0.000 0.000 0.000

** ** ** ** ** * ** ** ** ** Spearman's rho SC11 Correlation Coefficient .230 .277 .496 .348 .474 .148 .289 .202 .176 .184 1.000

391

Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.021 0.000 0.002 0.006 0.004 Correlation Coefficient .331** .386** .449** .386** .438** .341** .357** .342** .376** .259** .451** 1.000 SC12 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .337** .454** .409** .455** .479** .506** .514** .434** .440** .389** .353** .498** 1.000 SC13 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .395** .431** .231** .285** .336** .439** .419** .388** .506** .350** .211** .410** .489** 1.000 SC14 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.000 0.000 Correlation Coefficient .408** .450** .522** .454** .449** .457** .484** .479** .318** .311** .465** .442** .487** .458** 1.000 SC15 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 **. Correlation is significant at the 0.01 level (2-tailed). *. Correlation is significant at the 0.05 level (2-tailed).

392

Appendix Q1: KMO and Bartlett's Test for Sustainable Construction Approaches

Kaiser-Meyer-Olkin Measure of Sampling Adequacy. .915 Bartlett's Test of Sphericity Approx. Chi-Square 1571.909 df 105 Sig. .000

Appendix Q2: Communalities of Sustainable Construction Approaches

Code Sustainable Construction Approaches Initial Extraction SC1 Conduct comprehensive feasibility studies 1.000 .542 SC2 Set targets for allowable waste 1.000 .595 SC3 Appoint a waste management contractor 1.000 .722 SC4 Improved construction methods e.g. Industrialised building system 1.000 .612

SC5 Lean construction 1.000 .639 SC6 Effective teamwork among stakeholders 1.000 .685 SC7 Make waste reduction efforts financially beneficial 1.000 .538

SC8 Educate construction and management teams on waste reduction 1.000 .627

SC9 Avoid excavating unnecessary soil 1.000 .714 SC10 Use excavated soil elsewhere on the same construction site 1.000 .621

SC11 Use no-dig or trenchless technologies 1.000 .769 SC12 Provide space on site for the management of C&D waste 1.000 .592

SC13 Identify construction activities that can reuse materials 1.000 .625

SC14 Stock control measures (e.g. stock taking) 1.000 .508 SC15 Adopt building information modelling (BIM) and ICT tools 1.000 .553

Average .623 Extraction Method: Principal Component Analysis.

393

Appendix Q3: Total Variance of Sustainable Construction Approaches

Extraction Sums of Squared Rotation Sums of Squared Initial Eigenvalues Loadings Loadings % of Cumulative % of Cumulative % of Cumulative Component Total Variance % Total Variance % Total Variance % 1 6.765 45.103 45.103 6.765 45.103 45.103 3.848 25.653 25.653 2 1.505 10.034 55.137 1.505 10.034 55.137 2.763 18.421 44.074 3 1.070 7.136 62.273 1.070 7.136 62.273 2.730 18.199 62.273 4 .748 4.988 67.262 5 .661 4.409 71.670 6 .638 4.250 75.920 7 .556 3.706 79.626 8 .518 3.456 83.082 9 .450 3.001 86.083 10 .425 2.835 88.918 11 .402 2.681 91.599 12 .379 2.526 94.125 13 .341 2.276 96.402 14 .275 1.833 98.234 15 .265 1.766 100.000 Extraction Method: Principal Component Analysis.

394

Appendix R: Correlation Matrix of 3R Approaches

Correlations

- site rials

products is possible - site sorting and use of materials on use of materials on

- - - site On segregation of material wastes favour that systems Use segregation into their elements at the end of their useful life Use skips for segregation on specific mate Evaluate if salvage of used Use reusable formwork and scaffolding Re Re different site Use recycled materials Send waste materials to facility recycling Recycle waste on

On-site sorting and segregation of material Correlation Coefficient 1.000 wastes Sig. (2-tailed)

** Use systems that favour segregation into their Correlation Coefficient .683 1.000 elements at the end of their useful life Sig. (2-tailed) 0.000 Correlation Coefficient .555** .687** 1.000 Use skips for segregation on specific materials Sig. (2-tailed) 0.000 0.000

** ** ** Evaluate if salvage of used-products is Correlation Coefficient .600 .614 .639 1.000 possible Sig. (2-tailed) 0.000 0.000 0.000

Correlation Coefficient .270** .233** .168** .332** 1.000 Use reusable formwork and scaffolding Sig. (2-tailed) 0.000 0.000 0.009 0.000 Correlation Coefficient .287** .318** .210** .412** .681** 1.000

Re-use of materials on-site Sig. (2-tailed) 0.000 0.000 0.001 0.000 0.000

's rho Correlation Coefficient .287** .290** .232** .327** .485** .651** 1.000 Re-use of materials on different site Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000

** ** ** ** * ** ** Spearman Use recycled materials Correlation Coefficient .343 .432 .440 .391 .155 .323 .377 1.000

395

Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.016 0.000 0.000 - Correlation Coefficient .362** .461** .473** .318** 0.094 .279** .645** 1.000 Send waste materials to recycling facility 0.006 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.928 0.144 0.000 0.000

Correlation Coefficient .276** .426** .464** .293** 0.000 0.117 .245** .547** .666** 1.000 Recycle waste on-site Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.996 0.070 0.000 0.000 0.000 **. Correlation is significant at the 0.01 level (2-tailed). *. Correlation is significant at the 0.05 level (2-tailed).

396

Appendix R1: KMO and Bartlett's test for the 3R approaches

Kaiser-Meyer-Olkin Measure of Sampling Adequacy. .842 Bartlett's Test of Sphericity Approx. Chi-Square 1188.542 df 45 Sig. .000

Appendix R2: Communalities of the 3R approaches

3R approaches Initial Extraction On-site sorting and segregation of material wastes 1.000 .715 Use systems that favour segregation into their elements at the end of 1.000 .776 their useful life Use skips for segregation on specific materials 1.000 .732 Evaluate if salvage of used-products is possible 1.000 .714 Use reusable formwork and scaffolding 1.000 .760 Re-use of materials on-site 1.000 .826 Re-use of materials on different site 1.000 .720 Use recycled materials 1.000 .724 Send waste materials to recycling facility 1.000 .795 Recycle waste on-site 1.000 .730 Average .7492 Extraction Method: Principal Component Analysis.

Appendix R3: Total variance of the 3R approaches

2 1.751 17.513 63.305 1.751 17.513 63.305 2.366 23.663 51.886 3 1.161 11.614 74.919 1.161 11.614 74.919 2.303 23.034 74.919 4 .488 4.882 79.801

5 .439 4.394 84.195 6 .414 4.136 88.331 7 .338 3.379 91.710 8 .327 3.271 94.982

9 .279 2.794 97.776 10 .222 2.224 100.000 Extraction Method: Principal Component Analysis.

397

Appendix S: Correlation Matrix of Waste Minimisation Policies/Measures

Correlations

S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 Correlation Coefficient 1.000 S1 Sig. (2-tailed)

Correlation Coefficient .352** 1.000 S2 Sig. (2-tailed) 0.000

Correlation Coefficient .349** .516** 1.000 S3 Sig. (2-tailed) 0.000 0.000

Correlation Coefficient .177** .327** .319** 1.000 S4 Sig. (2-tailed) 0.006 0.000 0.000

Correlation Coefficient .138* .184** .296** .401** 1.000 S5 Sig. (2-tailed) 0.033 0.004 0.000 0.000

Correlation Coefficient .286** .254** .281** .343** .223** 1.000 S6 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.001

Correlation Coefficient .254** .409** .434** .437** .274** .400** 1.000 S7 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .284** .238** .284** .437** .298** .283** .461** 1.000 S8 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Spearman's rho

398

Correlation Coefficient .254** .312** .380** .301** .257** .264** .421** .449** 1.000 S9 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Correlation Coefficient .495** .336** .431** .282** 0.126 .375** .422** .502** .466** 1.000 S10 Sig. (2-tailed) 0.000 0.000 0.000 0.000 0.052 0.000 0.000 0.000 0.000

**. Correlation is significant at the 0.01 level (2-tailed). *. Correlation is significant at the 0.05 level (2-tailed).

399

Appendix S1: KMO and Bartlett's test of waste minimisation strategies

Kaiser-Meyer-Olkin Measure of Sampling Adequacy. .858 Bartlett's Test of Sphericity Approx. Chi-Square 641.433 df 45 Sig. .000

Appendix S2: Communalities of waste minimisation strategies

Code Initial Extraction S1 Construction waste disposal charging scheme (to encourage the construction 1.000 .600 workforce to consider 3R principles before disposal) S2 Step-wise incentive system (an award given to those producing low levels of 1.000 .475 waste) S3 Extended Producer Responsibility (producers’ responsibilities across the life cycle 1.000 .530 of their products especially when the products are discarded as waste) S4 Pay-as-you-throw (PAYT) / landfill charging scheme (requires construction 1.000 .600 workforce to pay for the amount of waste that they produce) S5 Landfill ban (outright ban on the disposal of reusable/recyclable construction 1.000 .497 materials) S6 Contractor’s willingness to pay (WTP) for waste management 1.000 .377 S7 Financial incentives for operatives (labourers) to sort and segregate waste 1.000 .528 S8 Appoint a waste manager (new position where someone is appointed to 1.000 .494 coordinate waste management procedures on site) S9 Use waste prediction tools (to generate waste forecasts) 1.000 .451 S10 Site waste management plan (SWMP) 1.000 .601 Average .515 Extraction Method: Principal Component Analysis.

400

Appendix S3: Total variance of waste minimisation strategies

2 1.160 11.601 51.535 1.160 11.601 51.535 2.473 24.729 51.535 3 .925 9.253 60.788 4 .800 7.997 68.785

5 .730 7.296 76.082 6 .593 5.931 82.012 7 .474 4.741 86.753 8 .469 4.686 91.439

9 .467 4.670 96.108 10 .389 3.892 100.000 Extraction Method: Principal Component Analysis.

401