DEVELOPMENT OF SELF-CURED GEOPOLYMER CEMENT A thesis submitted for the degree of Doctor of Philosophy by Teewara Suwan Department of Mechanical, Aerospace & Civil Engineering Brunel University London March 2016 ABSTRACT To support the concept of environmentally friendly materials and sustainable development, the low-carbon cementitious materials have been extensively studied to reduce amount of CO2 emission to the atmosphere. One of the efforts is to promote alternative cementitious binders by utilizing abundant alumina-silicate wastes from the industrial sectors (e.g. fly ash or furnace slag), among which “Geopolymer (GP) cement” has received most attention as it can perform a wide variety of behaviours, in addition to cost reduction and less environmental impacts. The most common geopolymer production, fly ash-based, gained some strength with very slow rate at ambient temperature, while the strength is evidently improved when cured in high (above room) temperature, e.g. over 40°C. The major challenge is to step over the limitation of heat curing process and inconvenience in practice. In this study, the testing schemes of (i) GP manufacturing in various processes, (ii) inclusion of ordinary Portland cement (OPC) in GP mixture, called GeoPC and (iii) GeoPC manufactured with dry- mixing method, have been intensively investigated through mechanical testing (Setting time, Compressive strength and Internal heat measurement) and mechanism analysis (XRD, FTIR, SEM and EDXA) in order to develop the geopolymers, achieving reasonable strength without external sources of heat curing. It is found that the proposed (dry) mixing process could have generated intensive heat liberation which was observed as a comparable factor to heat curing from any other external sources, enhancing the curing regime of the mixture. The additional calcium content in the developed GeoPC system not only resulted in an improvement of an early strength by the extra precipitation of calcium compounds (C,N-A-S-H), but also provided a latent heat from the reaction of its high potential energy compounds (e.g. OPC or alkaline activators). The developments from these approaches could lead to geopolymer production to achieve reasonable strength in ambient curing temperature known as “Self-cured geopolymer cement”, without external heat, and hence provide construction industry viable technologies of applying geopolymers in on-site and off-site construction. i ACKNOWLEDGEMENTS My PhD programme was completed successfully because of my kind and knowledgeable principal supervisor, Professor Dr Mizi Fan and supervisor Dr Nuhu Braimah. I sincerely appreciate your invaluable advice, guidance and support from day one to completion. You continually inspire me and demonstrate what it means to be a great advisor and researcher. I am honoured to have both of you as my academic advisors. I would like to thank the rest of my committee members – Professor Asif Usmani, Dr Binsheng (Ben) Zhang and Dr Mujib Rahman. I greatly appreciate the time and energy you gave to being my committee member, as well as your creative suggestions and comments. I also would like to express my appreciation to Dr Xiangming Zhou for your suggestions on geopolymer cement and my experimental works, as well as Neil Macfadyen, Simon Le Geyt and Paul Szadorski at civil engineering laboratory, for supporting all lab equipment, materials and trainings on my research project – Thank you so much, you are the best! I will also like to extend special thanks to Brunel ETC’s staff, Dr Lorna Anguilano, Ashley Howkins, Dr Jesus Ojeda and Nita Verma for your supports and great techniques on handling all equipment and machines. Thanks to my lovely friends, Jane Paphawasit, Samira Safari, Seyed Ghaffar, Gediminas Kastiukas and Dasong Dai for your help and kindness relating to my research work. Last but not least, an endless gratitude to my inspiration, my support, my encouragement, my everything – Papa, Mama, Note and Neth, including my beloved aunt, Pa Ni. ii TABLE OF CONTENTS ABSTRACT ........................................................................................................................... i ACKNOWLEDGEMENTS .................................................................................................. ii TABLE OF CONTENTS ..................................................................................................... iii LIST OF TABLES ............................................................................................................. viii LIST OF FIGURES ............................................................................................................. ix LIST OF ABBREVIATIONS ............................................................................................ xiii LIST OF SYMBOLS ........................................................................................................... xv PART 1 INTRODUCTION, LITERATURE REVIEW AND METHODOLOGY ............. 1 CHAPTER 1 INTRODUCTION .......................................................................................... 2 1.1 Background of Research .............................................................................................. 2 1.2 Aim of the Research ..................................................................................................... 3 1.3 Research Objectives ..................................................................................................... 4 1.4 Research Scope ............................................................................................................. 4 1.5 Research Significance .................................................................................................. 5 1.6 Organisation of Contents .............................................................................................. 6 CHAPTER 2 LITERATURE REVIEW ............................................................................... 9 2.1 Portland Cement and Fly Ash ...................................................................................... 9 2.1.1 Ordinary Portland cement ...................................................................................... 9 2.1.2 The use of pozzolanic admixture (fly ash) in Portland cement ........................... 15 2.2 Geopolymer Cement ................................................................................................... 17 2.2.1 Fundamentals of geopolymers ............................................................................. 17 2.2.2 Geopolymerization reaction and its chemistry .................................................... 19 2.2.3 Geopolymer binder constituents .......................................................................... 21 2.2.4 Design of geopolymer constituents...................................................................... 28 2.2.5 Curing procedures of geopolymers ...................................................................... 30 2.2.6 Properties and application of geopolymer cement ............................................... 34 2.3 Factors Influencing Geopolymer Properties at Ambient Temperature ...................... 38 2.3.1 High humidity curing ........................................................................................... 38 2.3.2 Concentration of alkaline activators .................................................................... 39 2.3.3 Fineness and shape of particles ............................................................................ 39 2.3.4 Mixing procedures ............................................................................................... 40 2.3.5 Alternative heat curing sources............................................................................ 40 iii 2.3.6 Calcium content in mixtures ................................................................................ 41 2.4 Remark ....................................................................................................................... 42 CHAPTER 3 MATERIALS AND TESTING METHODS ................................................ 45 3.1 Experimental Programme and Work Packages .......................................................... 45 3.2 Materials and Equipment ............................................................................................ 47 3.2.1 Ordinary Portland cement (OPC) ........................................................................ 47 3.2.2 Coal-fired fly ash ................................................................................................. 47 3.2.3 Alkaline solutions ................................................................................................ 48 3.2.4 Experimental equipment ...................................................................................... 49 3.3 Sample Preparation ..................................................................................................... 50 3.3.1 Portland cement paste .......................................................................................... 50 3.3.2 Geopolymer cement paste .................................................................................... 51 3.3.3 GeoPC pastes ....................................................................................................... 51 3.4 Testing of Physical and Mechanical Properties ......................................................... 52 3.4.1 Particle size distribution analysis ........................................................................