ﺑﺴﻢ اﻟﻠﮫ اﻟﺮﺣﻤﻦ اﻟﺮﺣﯿﻢ

Sudan University of Science and Technology

College of Graduate Studies

Using Gum Arabic as Viscosity Modifying Agent with Natural Pozzolana in Producing

Self-Compacting Concrete

إﺳﺘﺨﺪام اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ ﻋﺎﻣﻼً ﻣﻌﺪﻻً ﻟﻠﺰوﺟﺔ ﻣﻊ اﻟﺒﻮزوﻻﻧﺔ اﻟﻄﺒﯿﻌﯿﺔﻹ َ ﻧﺘﺎج اﻟﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ

A Thesis Submitted to Department of Structural Engineering, College of Engineering, in Partial Fulfillment of the Requirements for the Degree of Master of Science in Civil Engineering (Structures).

Prepared by: Hassan Alhodaibe Ibrahim Hassan Ibrahim

B.Sc. in Civil Engineering Khartoum University (2010)

Supervisor: Prof. Abdelrahman Elzubair Mohamed

July 2016

DEDICATIONS

To my Father,,,

Mother,,,

Brothers , Sisters ,,,

To my friends,,,

And to whom I belong.

Hassan Alhodaibe ,,,

ACKNOWLEDGMENT

I would like to express my sincere appreciation to Prof. Abdelrahman Elzubair Mohamed for his help and guidance in the preparation and development of this work. The constant encouragement, support and inspiration offered were fundamental to the completion of this research

Special thanks to Civil Engineering Department of Omdurman Islamic University for contribution in laboratory works and their continuous support. I would like to express my deep thanks for my friends for their assistance during the practical work of the research. Finally, I would like to thank everyone who gave me advice or assistance that contributed to complete this research.

ABSTRACT

Development of SCC in Sudan is highly needed to overcome many problems in the construction sector. The elimination of vibration for compacting concrete during placing through the use of SCC leads to better homogeneity, enhancement of working environment and improvement in the productivity.

This research presents experimental investigation on introducing the technology of self-compacting concrete (SCC) in the hot climate of Sudan using local materials. In this experimental work, SCC was made by the usual ingredients cement, fine aggregate, coarse aggregate and water plus Natural Pozzolana and Gum Arabic .Natural Pozzolana is used for replacement of cement and Gum Arabic as viscosity modifying agent VMA. Six mixes containing Natural Pozzolana as 10% replacement of cement with (0,1.5,2,3,7,10) percentages of Gum Arabic were used to investigate the possibility of obtaining acceptable fresh properties of SCC. The European Guidelines for Self Compacting Concrete were used to define and check SCC properties and tests. A control mix with zero Pozzolana and zero Gum Arabic was also used for comparison. According to these guidelines mixes (1,2,3) which contained 0.0%,1.5% and 2.0% of Gum Arabic respectively did not match SCC standard and properties. But mix (4) which contained 3% of Gum Arabic was found to be the most acceptable and suitable mix for SCC. Mixes (5,6) which contained 7% and10% of Gum Arabic respectively had acceptable slump flow but their cubes compressive strength results were very low .

The research concludes that 3% Gum Arabic as VMA and 10% Pozzolana Replacement produces SCC.

اﻟﻤﺴﺘﺨﻠﺺ

اﻟﺤﻮﺟﺔ ﻟﺘﻄﻮﯾﺮ اﻟﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ ﻛﺒﯿﺮة ﻓﻰ اﻟﺴﻮدان ﻟﺘﺠﺎوز اﻟﻌﺪﯾﺪ ﻣﻦ اﻟﻤﺸﺎﻛﻞ ﻓﻰ ﻣﺠﺎل اﻟﺘﻨﻔﯿﺬ . إﻟﻐﺎء ﻋﻤﻠﯿﺔ اﻟﺪﻣﻚ ﻓﻰ اﻟﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ ﯾﻨﺘﺞ ﻋﻨﮫ زﯾﺎدة ﺗﺠﺎﻧﺲ و ﺗﺤﺴﯿﻦ ﺑﯿﺌﺔ اﻟﻌﻤﻞ ﺧﻼل ﻋﻤﻠﯿﺔ اﻟﺼﺐ ﺑﺎﻻﺿﺎﻓﺔ إﻟﻰ زﯾﺎدة اﻹﻧﺘﺎﺟﯿﺔ.

ھﺬا اﻟﺒﺤﺚ ﯾﻌﺮض إﺳﺘﻘﺼﺎءات ﻣﻌﻤﻠﯿﺔ ﻟﺘﻘﺪﯾﻢ ﺗﻜﻨﻮﻟﻮﺟﯿﺎ اﻟﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ ﻓﻰ ﺟﻮ اﻟﺴﻮدان اﻟﺤﺎر ﺑﺈﺳﺘﺨﺪام ﻣﻮاد طﺒﯿﻌﯿﺔ ﻣﺤﻠﯿﺔ. ﻓﻰ ھﺬه اﻹﺧﺘﺒﺎرات اﻟﻤﻌﻤﻠﯿﺔ ﺗﻢ ﻋﻤﻞ اﻟﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ ﻣﻦ اﻟﻤﻜﻮﻧﺎت اﻟﻌﺎدﯾﺔ اﻷﺳﻤﻨﺖ , اﻟﺮﻛﺎم اﻟﻨﺎﻋﻢ , اﻟﺮﻛﺎم اﻟﺨﺸﻦ و اﻟﻤﺎء ﺑﺎﻹﺿﺎﻓﺔ ﻟﻠﺒﻮزوﻻﻧﺔ اﻟﻄﺒﯿﻌﯿﺔ و اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ .ﺗﻢ اﺳﺘﺨﺪام اﻟﺒﻮزوﻻﻧﺔ اﻟﻄﺒﯿﻌﯿﺔ ﻹﺳﺘﺒﺪال اﻷﺳﻤﻨﺖ و اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ ﻣﻌﺪﻻ ُ ﻟﻠﺰوﺟﺔ .

ﺗﻢ إﺳﺘﺨﺪام ﺳﺘﺔ ﺧﻠﻄﺎت ﺗﺤﺘﻮى ﻧﺴﺒﺔ 10% ﻣﻦ اﻟﺒﻮزوﻻﻧﺔ اﻟﻄﺒﯿﻌﯿﺔ ﻹﺳﺘﺒﺪال اﻷﺳﻤﻨﺖ و اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ ﺑﻨﺴﺐ %(0,1.5,2,3,7,10) ﻹﺳﺘﻘﺼﺎء إﻣﻜﺎﻧﯿﺔ اﻟﺤﺼﻮل ﻋﻠﻰ ﺧﻮاص اﻟﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ اﻟﻤﻘﺒﻮﻟﺔ.

ﺗﻢ إﺳﺘﺨﺪام ﺗﻌﻠﯿﻤﺎت اﻟﻤﻨﻈﻤﺔ اﻷورﺑﯿﺔ ﻟﻠﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ ﻟﻤﺮاﻗﺒﺔ و ﺗﻌﺮﯾﻒ اﻟﺨﻮاص واﻹﺧﺘﺒﺎرات اﻟﺨﺎﺻﺔ ﺑﺎﻟﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ. أﯾﻀﺎ ُ ﺗﻢ إﺳﺘﺨﺪام ﺧﻠﻄﺔ ﺗﺤﻜﻢ ﻟﻠﻤﻘﺎرﻧﺔ ﺗﺤﺘﻮى ﻋﻠﻰ ﻧﺴﺒﺔ ﺻﻔﺮ ﻣﻦ اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ و ﻧﺴﺒﺔ ﺻﻔﺮ ﻣﻦ اﻟﺒﻮزوﻻﻧﺔ اﻟﻄﺒﯿﻌﯿﺔ. ﺑﻨﺎءا ُ ﻋﻠﻰ ھﺬه اﻟﻤﻮﺟﮭﺎت اﻟﺨﻠﻄﺎت (3,2,1) واﻟﺘﻰ ﺗﺤﺘﻮى ﻋﻠﻰ ﻧﺴﺒﺔ 0% , 1.5% , 2% ﻣﻦ اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ ﺑﺎﻟﺘﺮﺗﯿﺐ ﻟﻢ ﺗﻄﺎﺑﻖ ﺧﻮاص و ﻣﻌﺎﯾﯿﺮ اﻟﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ. ﻟﻜﻦ اﻟﺨﻠﻄﺔ (4) واﻟﺘﻰ ﺗﺤﺘﻮى ﻋﻠﻰ ﻧﺴﺒﺔ 3% ﻣﻦ اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ وﺟﺪت ﻟﺘﻜﻮن اﻷﻛﺜﺮ ﻗﺒﻮﻻ ُ و ﻣﻼﺋﻤﺔ ُ ﻟﻠﺨﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ. اﻟﺨﻠﻄﺎت (6,5) واﻟﺘﻰ ﺗﺤﺘﻮى ﻋﻠﻰ ﻧﺴﺒﺔ %7 و % 10 ﻣﻦ اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ ﺑﺎﻟﺘﺮﺗﯿﺐ ﻟﺪﯾﮭﺎ ﻗﯿﻤﺔ ﻣﻘﺒﻮﻟﺔ ﻹﺧﺘﺒﺎر اﻟﮭﺒﻮط وﻟﻜﻦ ﻗﯿﻤﺔ ﻣﻘﺎوﻣﺔ اﻹﻧﻀﻐﺎط ﻛﺎﻧﺖ ﻗﻠﯿﻠﺔ ﺟﺪا ُ.

اﻟﺒﺤﺚ ﯾﻠﺨﺺ أن ﻧﺴﺒﺔ 3% ﻣﻦ اﻟﺼﻤﻎ اﻟﻌﺮﺑﻰ و ﻧﺴﺒﺔ 10% ﻣﻦ اﻟﺒﻮزوﻻﻧﺔ اﻟﻄﺒﯿﻌﯿﺔ ﻹﺳﺘﺒﺪال اﻷﺳﻤﻨﺖ ﺗﻨﺘﺞ ﺧﺮﺻﺎﻧﺔ ذاﺗﯿﺔ اﻟﺪﻣﻚ.

Table of Contents

Dedications……………………………………………………………………………………………………………………..I

Acknowledgment…………………………………………………………………………………………………………...II

Abstract, English…………………………………………………………………………………………………………....III

Abstract, Arabic…………………………………………………………………………………………………………..…IV

Table of contents……………………………………………………………………………………………………………V

List of figures………………………………………………………………………………………………………………..VII

List of tables………………………………………………………………………..………………………………………..VIII

CHAPTER ONE: INTRODUCTION...... 1 1.1Overview ...... 1 1.2 Problem Statement ...... 4 1.3 Objectives ...... 5 1.4 Methodology ...... 5 1.5 Thesis Layout ...... 6 CHAPTER TWO: LITERATURE REVIEW ...... 7 2.1 Introduction ...... 7 2.2 History of Developing SCC ...... 7 2.3 Examples of structures built of Self-Compacting Concrete …………………………………….……9

2.4 Defining the properties of fresh Self-Compacting Concrete……………………… …………..….14

2.5 Acceptance criteria for SCC ...... 16 2.5.1 Consistence classification ...... 18 2.6 Choice of Matrials ...... 21 2.7 Natural Pozzolanas ...... 23 2.8 Gum Arabic...... 27 2.9 Mix proportions ...... 28 2.10.1 Summary of Researchers Finding: ...... 39 CHAPTER THREE: EXPERIMENTAL WORK ...... 38 3.1 Introduction ...... 38 3.2 Constituent Material properties ...... 38 3.2.1 Portland Cement ...... 39 3.2.2 Coarse aggregates: ...... 40 3.2.3 Fine aggregates ...... 41 3.2.4 Natural Pozzolana ...... 42 3.2.5 Liquid Gum Arabic ...... 42 3.3.1 Procedure for SCC mix design ...... 46 3.4 Casting, curing and testing ...... 48 3.5 Calculation of initial key proportions ...... 48 3.5.2 Calculation of Mortar Volume...... 49 3.5.3 Calculation of Sand Volume...... 49 3.5.4 Calculation of Paste Volume ...... 49 3.5.5 Calculation of Cement Paste Composition ...... 49 3.5.6 Calculation of Constituent Materials for Concrete...... 50 3.6 Test Methods………………………………………………………………………… … …………………………………………...... 51

CHAPTER FOUR: ANALYSIS AND DISCUSSION OF RESULTS…………………………………………………………………55

4.1 Introduction……………………………………………………………………………...... 55

4.2 Test Result…………………………………………………………………………………………………………………………..…..56

4.3 Analysis of fresh SCC properties test results…………………………………………………………………..…………65

4.3.1 Effect of Gum Arabic in the slump flow test………………………………………………………………………..….65

4.3.2 Effect of Gum Arabic in the T500 time test…………………………………….……...... 66

4.4 Analysis of hardened SCC properties test results………………………………………………………………..…..67

4.4.1Effecvt of Natural Pozzolana in Concrete Compressive strength………………….………………………...68

4.4.2 Effect of Gum Arabic in the cubes compressive strength……………………………………………………...69

CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS ……………………………………………………………73

5.1 Conclusion……………………………………………………………………………………………………………………………..73

5.2 Recommendations………………………………………..…….…….…………………………………………………………..75

References…….….………………………………………………………………….……………………………………………..…76

Appendices ………………………………………………………………………………………………………………80

List of Figures

Fig.(2.1) Burj Dubai ...... 11 Fig.(2.2) Arlanda Airport Control Tower ...... 12 Fig.(2.3) National Museum of 21st Century Arts in Rome ...... 13 Fig.(2.4) Usce Shoping Center ...... 14 Fig.(2.5) Metakaolin, acalained clay ...... 24 Fig.(2.6) General purpose construction using pozzolna...... 26 Fig.(2.7) Hashab ...... 28 Fig.(3.1) Bayouda Natural Pozzolana ...... 43 Fig.(3.2) Mix Design Procedure ...... 45 Fig.(3.3)Slump flow test and T500 time test ...... 52 Fig.(3.4)Sump flow test ...... 54 Fig.(3.5) T500 time test ...... 54 Fig.(4.1) Effect of Gum Arabic on slump ...... 66 Fig.(4.2) Effect of Gum Arabic on T500 test...... 67 Fig.(4.3) Effect of Bayouda Natural Pozzolana in Concrete Compressive strength ...... 68 Fig.(4.4) Effect of Gum Arabic in Cubes compressive strength ...... 69 Fig.(4.5) Segregation in mix(5) cubes...... 70 Fig.(4.6) Segregation in mix (6) cubes ...... 71

List of Tables

Table (2.1) Slump flow classes...... 19 Table (2.2) Viscosity flow classes ...... 20 Table (2.3 ) Specification and classes of supplementary cementitious materials...... 25 Table (2.4) Typical range of Self compacting concrete ...... 30 Table (3.1) Chemical composition of the cement ...... 39 Table (3.2) Physical properties of the cement ...... 40 Table (3.3) Properties of the coarse aggregate ...... 40 Table (3.4) Sieve Analysis of coarse aggregate ...... 41 Table (3.5) Properties of the fine aggregate ...... 41 Table (3.6) Sieve analysis of fine aggregate ...... 42 Table (3.7) The chemical analysis of Bayouda Natural Pozzolana ...... 42 Table (3.8 ) Constituent Materials of mixes...... 51 Table (3.9 ) Slump flow classification ...... 53 Table (4.1) Control mix,without additive ...... 57 Table (4.2) Mix(1) ...... 58 Table (4.3) Mix(2) ...... 59 Table (4.4) Mix(3) ...... 60 Table (4.5) Mix(4) ...... 61 Table (4.6) Mix(5) ...... 62 Table (4.7) Mix(6) ...... 63 Table (4.8) Average of compresive strength,slump and T500 testes...... 64 Table (4.9) Reduction of compressive strength in mixes ...... 70

CHAPTER ONE

INTRODUCTION

1.1 Overview

As of 2012, more than 25 billion tones of Portland cement concrete is produced annually making it the world’s most widely used manufactured material (WBCSD, 2009). Even though the reasons for concrete’s dominance are diverse (Mehta and Monteiro, 2006), the massive production and consumption cycle of concrete have significant environmental impacts, making the concrete industry unsustainable (Mehta, 2001). Currently, Portland cement concrete production accounts for around 7% of anthropogenic carbon dioxide (CO2) emissions annually (Mehta, 2001). Most of the emissions are attributable to the production of Portland cement clinker; the active ingredient in Portland cement ([IEA] and [WBCSD], 2009). Using an increased proportion of supplementary cementing materials (such as natural pozzolan (NP) and fly ash) provides a sustainable solution, while yielding concrete mixtures with high workability, high durability, and comparable ultimate strength. Self-compacting concrete (SCC) was first developed in Japan in 1988 in order to achieve durable concrete structures by improving quality in the construction process. It was also found to offer economic, social and environmental benefits over traditional vibrated concrete construction (Krishna Murthy, NarasimhaRao, Ramana Reddy and Vijaya sekhar Reddy,2012). Research and development work into SCC in Europe began in Sweden in the 1990s and now nearly all the countries in Europe conduct some form of research and development into the material (International symposium, Stockholm, 1999). Once the fully compliant SCC is supplied to the point of application then the final operation of casting requires very little skill or manpower compared with traditional concrete to produce uniformly dense concrete. Because of vibration being unnecessary, the noise is reduced and the risk of developing problems due to the use of vibrating equipment is reduced. Fewer operatives are required, but more time is needed to test the concrete before placing. In addition to the benefits described above, SCC is also able to provide a more consistent and superior finished product for the client, with less defects. Another advantage is that less skilled labour is required in order for it to be placed, finished and made good after casting. As the shortage of skilled site labour in construction continues to increase in the UK and many other countries (International symposium, Stockholm, 1999), this is an additional advantage of the material which will become increasingly important. With the ongoing technological advances, the design and placement techniques of concrete are also changing. The ultimate target is the freedom in design while considering improved productivity, profitability, and sustainability. Self Compacting Concrete is highly engineered concrete mixtures obtained by optimizing normal concrete ingredients with a superplasticizer and a viscosity modifying agent (VMA) (Bartos,2000).

SCC is needed to overcome many difficulties, for example casting concrete in tall buildings, huge foundations, bridges, and long spans, where self compacting properties are required for making the pumping process easy and possible. For deteriorated structures which need rehabilitation and strengthening, SCC is recommended in to provide small cross sections able to carry existing or new loads. Building elements strengthened with SCC are usually densely reinforced. The small distance between reinforcing bars and the small spaces provided by framework, especially in the repair works, may lead to defects in concrete such as honeycombing and segregation. If concrete is self compacting, the production of densely reinforced strengthened building element from high strength concrete with high homogeneity would be an easy work.

But it is rarely used in Sudan , the hot climate and the available natural materials in Sudan need investigation to confirm the possibility of producing Self-compacting concrete with all it’s benefits.

In this study the superplasticizer was replaced with Gum Arabic as a viscosity modifying agent and local natural pozzolan from Bayouda desert was used for replacement of cement .

1.2 Problem Statement

The issue of producing SCC in the hot climate of Sudan by using local materias Natural Pozzalana as a replacement of cement and Gum Arabic as a viscosity modify agent instead of superplasticizer needs to be studied . Addding Gum Arabic to mix increase flowability and workability to concrete [Abdeljaleel,Hassaballa,Mohmed(2012)], while adding local pozzolana increase the compressive strength of concrete [Osman Alsr Osman Dabolk (2010)] .Results are compared in terms of compressive strength development and durability performance with reference concrete mixes that have no gum admixture.

1.3 Objectives

The main objectives of this reserch are:

1. To produce concrete based on the current mix proportion using local materials by adding Natural Pozzalana and Gum Arabic .

2. To obtain the fresh properties such as workability of the produced concrete.

3. To obtain the hardened properties such as compressive strength of the produced concrete

4.To investigate the possibility of the product being SCC.

1.4 Methodology

The following methodology was followed to achieve the research objectives.

1- Conducting comprehensive literature review related to subject of SCC.

2- Selection of suitable ingredient materials required for producing SCC, including cement, aggregates, water, Natural Pozzalana and Gum Arabic .

3- Producing different mixes with 10% pozzolana as a replacement, with different percentage of Gum Arabic .

4- Evaluating physical and mechanical properties of samples by performing the standard laboratory tests required for producing SCC and comparison of the results to the available standards.

5- Analysis of the results ,drawing conclusions and presenting recommendation.

1.5 Thesis Layout

The thesis contain five chapters organized as follows:

Chapter 1 (Introduction)

Chapter one gives a general overview about SCC and its main advantage in construction, effect of adding local material to concrete mix. Research problem statement and objectives and methodology used to achieve the research objectives are detailed together with thesis layout.

Chapter 2 (Literature Review)

Chapter two a general overview about normal SCC, reason for developing of SCC,the main advantages of application of self compacting concrete on site, general overview about Natural Pozzolana and benefits of adding it to concrete mix , general overview about Gum Arabic benefits of adding it to concrete mix , discusses the history of SCC, acceptance criteria for SCC, mixture proportions and short summary of various reports, papers and articles that were found to be relevant to this study.

Chapter 3 (Experimental Work)

Chapter three reviews the materials that were used in producing SCC and their properties, mix design of SCC, testing program and equipments used in the testing procedures , casting and curing .

Chapter 4 (Analysis and discussion of laboratory test result)

Chapter four illustrates the test results including the fresh and hardened results, the analysis of the fresh properties test , and the analysis of the hardening properties test results. Chapter 5 (Conclusions and Recommendations)

Chapter five included the concluding remarks, main conclusions drawn from this research and recommendations for further studies.

CHAPTER TWO

LITERATURE REVIEW

2.1 Introduction

An extensive literature review pertaining to SCC was conducted. A wealth of information was found in the literature and was studied with respect to different aspects of SCC, such as history of developing SCC, reasons, benefits, fresh and harden concrete properties, mixture proportioning methods and summary of various reports and papers that were found to be relevant to this study.

2.2 History of Developing SCC

The idea of a concrete mixture that can be compacted into every corner of a form work, purely by means of its own weight and without the need for vibration, was first considered in 1983 in Japan, when concrete durability, constructability and productivity became a major topic of interest in the country. During this period, Japan was suffering a reduction in the number of skilled workers in the construction industry which directly affected the quality of the concrete as placed. Okamura proposed the use of SCC in 1986 (Okamura.H,1997).Studies to develop SCC, including a fundamental study on the workability of concrete, were carried out by Ozawa at the University of Tokyo (Ozawa K,1989) , and by 1988 the first practical prototypes of SCC were produced. By the early 1990’s Japan started to develop and use SCC and, as of 2000, the amount of SCC used for prefabricated products and ready-mixed concrete in Japan was over (400,000 m3) (Arediwala , 2012) .In 1996, several European countries formed the “Rational Production and Improved explore the significance of published achievements in SCC and develop applications to take advantage of the potentials of SCC. Since then, SCC has been used successfully in a number of bridges, walls and tunnel linings in locations in Europe, interest in SCC has grown in the United States, particularly within the precast industry (Arediwala , 2012.) SCC has been used in several commercial projects. ,Numerous research studies have been conducted recently with the objective of developing raw material requirements, mixture proportions, material requirements and characteristics, and test methods necessary to routinely implement SCC. The latest studies of SCC focused on improved reliability and prediction of properties, production of a dense and uniform surface texture, improved durability, and both high strength and earlier strength permitting faster construction and increased productivity.

Self-compacting concrete (SCC) has many advantages and benefits but the main benefits of using it may be summarized as[(Arediwala , 2012.) and (Mehta, 2001)]:

• No vibration of fresh concrete is necessary during placement into forms. • Placement of concrete is easier. • Faster and more efficient placement of fresh concrete is achieved. Total concreting time is reduced. • Noise level on construction site is reduced. Thus the number of working hours on the construction site can be increased and the night shift in urban zones is enabled. • Energy consumption is reduced. • Required number of workers on construction site is reduced. • Safer and healthier working environment is obtained. Upon self- compacting concrete hardening in structures. • High quality of placed concrete is achieved, regardless the skill of the workers. • Good bond between concrete and reinforcement is obtained, even in congested reinforcement. • High quality of concrete surface finish is obtained with no need for subsequent repair. • With a better final appearance of concrete surface, smooth wall surfaces and flat floor. surfaces that need no further finishing are obtained. • Improved durability of structures is achieved. • Maintenance costs are reduced.

2.3 EXAMPLES OF STRUCTURES BUILT OF SELF-COMPACTING CONCRETE :

Earliest research in design of self-compacting concrete mixes began in the mid-eighties in the twentieth century in Japan. In 1986, Okamura, Kochi University, Japan, was the first to propose concrete that would be placed under the influence of self-weight only. The new technology was possible owing to the development of concrete superplasticizers which had been developed during the previous decades. After an extremely successful initial application in actual structures in Japan, the application of self-compacting concrete began in the entire world (Ruža Okrajnov-Bajić and Dejan Vasović,2009) . Extensive testing of physical and mechanical properties of SCC was carried out during the two past decade. This was followed by economic analyses which confirmed the rationality of SCC application. Practical application was extended from large infrastructure buildings (bridges, tanks, retaining walls, tunnels, etc.) onto architectural buildings also. SCC appears here as a structural material in load-bearing members but at the same time it also appears frequently as architectural concrete. Architectural concrete is defined by the American Concrete Institute as “concrete which will be permanently exposed to view and which therefore requires special care in selection of the concrete materials, forming, placing and finishing to obtain the desired architectural appearance” (Ruža Okrajnov-Bajić and Dejan Vasović,2009). Several characteristic examples are shown below. a) Burj Dubai The Burj Dubai structure represents the state of- the-art in super high- rise buildings. During its construction the most recent accomplishments in all fields have been united, including concrete production technology. The designed concretes were obtained using Portland cement combined with silica fume, fly ash or ground slag (http://www.burjdubai.com/ ) . In course of construction of the building the concrete was pumped to higher and higher heights so it was necessary to provide extraordinary flowing ability of concrete through pipes. A world record was achieved: on November 8, 2007 highest vertical concrete pumping for buildings, 601m, was performed.

Figure (2.1): Burj Dubai, (http://www.burjdubai.com/ )

b) Arlanda Airport Control Tower,Stockholm, Sweden This tower was designed by Wingårdh Arkitektkontor AB. The total height of the tower is 83 m. The tower was completed and opened in 2001. Today it represents a symbol of Stockholm. SCC was used in order to achieve the concreting speed of a standard floor height h=3.27m in a 4 day climbing cycle of formwork and to ensure high-quality concrete placing without vibration. The decreased noise level during concrete placing enabled concreting during the night shift (http://en.wikipedia.org/wiki/File:Arlanda_Flightower.jpg) .

Figure (2.2): Arlanda Airport Control Tower, (http://en.wikipedia.org/wiki/File:Arlanda_Flightower.jpg) .

c) National Museum of 21st Century Arts (MAXXI) in Rome, Italy MAXXI was designed by Zaha Hadid. The building is characteristic for its winding exhibition space formed of reinforced concrete walls with glass roof. The concrete was cast along the entire lengths of the walls to avoid construction joints. This amounted up to 70 meters in length and 9 m in height in some members. To avoid segregation, the height from which the fresh concrete was poured was limited to maximum 15cm (Ruža Okrajnov-Bajić and Dejan Vasović,2009). Application of powdered limestone and epoxyresin additives provided perfectly smooth surface finish of concrete walls. To prevent development of excessive heat in fresh concrete, concreting was performed only when the temperature was below 25oc.

Figure (2.3): National Museum of 21st Century Arts in Rome, Italy, model, (http://www.maxxi.parc.beniculturali.it/english/museo.htm ) d) Ušće Shopping Center The Ušće Shopping Center was designed by a company from Belgrade, "ARCVS. Upon opening on March 31, 2009, Belgrade gained the largest Shopping centre in the region with 130,000 m2 in area (Ruža Okrajnov-Bajić and Dejan Vasović,2009). Peripheral walls of underground structures were built with SCC. Used fresh concrete reached flow ability 850mm.Hardened concrete was MB 40 . Columns of underground floors were also made with SCC. Flow ability of fresh concrete was 900mm, and class of hardened concrete was MB60. Concrete in foundation slabs was SCC, with flow ability of fresh concrete 900mm. Hardened concrete was MB40. Foundation slab thickness of 30cm provided complete watertight concrete.

These are only some of the most recent and most modern architectural buildings in which SCC was used. It is expected that the implementation of SCC in the future be more frequent and wider. Basics in technology of self- compacting concretes are described in the following sections.

Figure (2.4): Ušće Shopping Center, (Ruža Okrajnov-Bajić and Dejan Vasović,2009)

2.4 DEFINING THE PROPERTIES OF FRESH SELF-COMPACTING CONCRETE :

Behavior and usability of fresh self compacting concrete can be defined with four key properties of fresh concrete mix:

• Slump-flow – flow ability is a property of fresh concrete mix to flow and fully fill complex formwork under action of self-weight only (Ruža Okrajnov-Bajić and Dejan Vasović,2009) . This is the first, essential property, and therefore it is always (e.g. with every new batch on construction site) necessary to perform the slump flow test.

• Viscosity is the resistance of the fresh concrete to flow once it has already started to flow. We can also speak of density of concrete as a fluid. Through terms of time we can gain an insight into rate of movement of fresh concrete mass. Low- viscosity concrete will have large initial flow and then it will stop. High-viscosity concrete will flow slowly but it will continue to move in a longer period of time. The reciprocal of viscosity is called fluidity. Fluidity can be defined as flow ability in a certain period of time (Ruža Okrajnov-Bajić and Dejan Vasović,2009). • Passing ability is a property of fresh concrete mix to find its way through congested reinforcement assemblies or small openings between reinforcing bars. When defining the necessary SCC passing ability, geometry, reinforcement quantity and arrangement, maximum aggregate grain size and previously adopted slump-flow and viscosity are taken into account (Ruža Okrajnov-Bajić and Dejan Vasović,2009). The dimension of the smallest opening (limit opening) through which the SCC must continually pass is defined. Testing of this property must be especially emphasized since in a large number of structures the reinforcing bars are spaced at a sufficient distance thus enabling SCC to bypass them without any problem and to fill the space between them (Petersson,1996).

• Segregation resistance – stability is a feature of maintaining constant content of all components in the mix during transport and placing, without segregation of coarser aggregate grains or water bleeding. If the stability of the mix is not sufficient, two types of segregation occur, in respect of time and place of occurrence (Ruža Okrajnov-Bajić and Dejan Vasović,2009) : 1) External segregation occurs during transport or placing concrete into formwork. It is manifested by visible cement slurry bleeding in the first wave of concrete and by piling of coarser aggregate grains in front of obstacles or near the location where the concrete is placed into the structure. 2) Internal segregation occurs after the concrete has been placed into forms, before cement starts setting. Coarse aggregate grains settle in the lower layers of concrete section and cement slurry bleeds on the surface. Internal segregation has the worst influence in high elements (columns, walls). In thin plates this phenomenon gives weak surface finish and causes cracks. Segregation resistance becomes a very significant parameter in self-compacting concretes with higher slump–flow classes or in placing which can be favorable for segregation (when placing concrete from a larger height or along longer flow path). Only in these cases it is necessary to define the segregation resistance class.

2.5 Acceptance criteria for SCC

In 2002 EFNARC published their “Specification & Guidelines for Self- Compacting concrete” which, at that time, provided state of the art information for producers and users. Since then, much additional technical information on SCC has been published but European design, product and construction standards do not yet specifically refer to SCC and for site applications this has limited its wider acceptance, especially by specifiers and purchasers (EFNARC, 2002).

In 2004 five European organizations BIBM, CEMBUREAU, ERMCO, EFCA and EFNARC, all dedicated to the promotion of advanced materials and systems for the supply and use of concrete, created a “European Project Group” to review current best practice and produce a new document covering all aspects of SCC. This document “The European Guidelines for Self Compacting Concrete” serves to particularly address those issues related to the absence of European specifications, standards and agreed test methods (The European Guidelines for Self Compacting Concrete,2005).

“The European Guidelines for Self Compacting Concrete” represent a state of the art document addressed to those specifiers, designers, purchasers, producers and users who wish to enhance their expertise and use of SCC. The Guidelines have been prepared using the wide range of the experience and knowledge available to the European Project Group. The proposed specifications and related test methods for ready-mixed and site mixed concrete, are presented in a pre- normative format, intend to facilitate standardisation at European level. This approach should encourage increased acceptance and utilisation of SCC. “The European Guidelines for Self Compacting Concrete” define SCC and many of the technical terms used to describe its properties and use. They also provide information on standards related to testing and to associated constituent materials used in the production of SCC (The European Guidelines for Self Compacting Concrete,2005). Durability and other engineering properties of hardened concrete are covered to provide reassurance to designers on compliance of SCC with EN 1992-1-1 Design of concrete structures (Eurocode 2)

2.5.1 Consistence classification

2.5.1.1 Slump-flow

Slump-flow value describes the flowability of a fresh mix in unconfined conditions. It is a sensitive test that will normally be specified for all SCC, as the primary check that the fresh concrete consistence meets the specification. Visual observations during the test and/or measurement of the T500 time can give additional information on the segregation resistance and uniformity of each delivery.

The following are typical slump-flow classes for a range of applications (The European Guidelines for Self Compacting Concrete,2005) :

SF1 (550 - 650 mm) is appropriate for: • unreinforced or slightly reinforced concrete structures that are cast from the top with free displacement from the delivery point (e.g. housing slabs)

• casting by a pump injection system (e.g. tunnel linings)

• sections that are small enough to prevent long horizontal flow (e.g. piles and some deep foundations).

SF2 (660 - 750 mm) is suitable for many normal applications (e.g. walls, columns)

SF3 (760 – 850 mm) is typically produced with a small maximum size of aggregates (less than 16 mm) and is used for vertical applications in very congested structures, structures with complex shapes, or for filling under formwork. SF3 will often give better surface finish than SF 2 for normal vertical applications but segregation resistance is more difficult to control.

Table (2.1): Slump flow classes (The European Guidelines for Self Compacting Concrete,2005).

Target values higher than 850 mm may be specified in some special cases but great care should be taken regarding segregation and the maximum size of aggregate should normally be lower than 12 mm.

2.5.1.2 Viscosity

Viscosity can be assessed by the T500 time during the slump-flow test or assessed by the V-funnel flow time. The time value obtained does not measure the viscosity of SCC but is related to it by describing the rate of flow. Concrete with a low viscosity will have a very quick initial flow and then stop. Concrete with a high viscosity may continue to creep forward over an extended time. Viscosity (low or high) should be specified only in special cases such as those given below (The European Guidelines for Self Compacting Concrete,2005) . It can be useful during mix development and it may be helpful to measure and record the T500 time while doing the slump-flow test as a way of confirming uniformity of the SCC from batch to batch. VS1/VF1 has good filling ability even with congested reinforcement. It is capable of self-levelling and generally has the best surface finish. However, it is more likely to suffer from bleeding and segregation. VS2/VF2 has no upper class limit but with increasing flow time it is more likely to exhibit thixotropic effects, which may be helpful in limiting the formwork pressure or improving segregation resistance. Negative effects may be experienced regarding surface finish (blow holes) and sensitivity to stoppages or delays between successive lifts.

Table (2.2) Viscosity flow classes (The European Guidelines for Self Compacting Concrete,2005).

The typical acceptance criteria for self-compacting concrete with a maximum aggregate size up to 20 mm, as stated before, are shown in Table (2.1) method according to European Guidelines for Self-Compacting Concrete (The European Guidelines for Self Compacting Concrete,2005) . Results outside these acceptance criteria may be acceptable in specific conditions such as large spaces between reinforcement, layer thickness less than 500 mm, short distance of flow from point of discharge, fewer obstructions in the formwork, simpler design of formwork, etc. However, causes for not fulfilling the specified requirements can be very diverse. In (Tables 2.1 and 2.2) possible causes for not fulfilling the requirements of the different tests is provided. As indicated in these tables, the four possible predominant causes are (The European Guidelines for Self Compacting Concrete,2005);

1. Yield value: The force (shear stress) that must be exerted on a material for initial flow.

2. Viscosity: The resistance of a material to flow due to internal friction.

3. Blockage: When a material cannot flow through a specified opening due to interlocking of the aggregate particles.

4. Segregation: When a material doesn’t remain homogeneous in composition during placement.

2.6 CHOICE OF MATERIALS

The following are the key steps in choosing materials for self-compacting concrete mixes: Defining the type of aggregate, maximum grain size and grading curve. Maximum aggregate grain size is limited to 8 – 20 mm. Decreasing maximum grain size results in lower local stresses in cement paste, influences improvement of concrete workability without vibration and prevents segregation of coarse grains (Ruža Okrajnov-Bajić and Dejan Vasović,2009). In normal strengths, natural, river aggregate is used. With its smooth surfaces it contributes to better flowability and workability. Only in cases where high classes of hardened concrete are required, crushed aggregate can also be applied. Aggregate grading curve is usually continuous, with maximum quantity of fine aggregate. Adopting mineral additions: Mineral additions are inorganic materials that are added to concrete. They are classified into two groups (Ruža Okrajnov-Bajić and Dejan Vasović,2009): - Inert Fillers which include powdered limestone, and pigments. - Pozzolanic or latent hydraulic additions: those are ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF), synthetic silica and natural pozzolana. The following are the most important properties of mineral additions: High level of fineness, high pozzolanic activity and compatibility with other ingredients of the mix. Moistened fine particles of mineral additions "lubricate" like spheres the cement grains thus reducing friction in fresh concrete mix. They give the concrete better workability and higher cohesion and impermeability. Water bleeding from fresh concrete mix is significantly reduced. Adopting the type and quantity of hydraulic binder: As a rule, the mixture for SCC is designed with a large quantity of cement. Expected cement quantities are 350– 500 kg/m3(The European Guidelines for Self Compacting Concrete,2005 . If reduction of hydration heat is desired when designing the mixture, cements with low hydration heat should be applied, a part of the cement mass should be replaced by puzzolana or special measures for reducing temperature of the fresh concrete mix should be provided. Adopting the water/powder ratio, with simultaneous application of chemical Admixtures (Ruža Okrajnov-Bajić and Dejan Vasović,2009). Self-compacting concrete is much more sensitive to water content than ordinary concretes. The specified water quantity must be sufficient for chemical reaction with all hydraulic binders. Larger quantity of cement requires a larger quantity of water in a fresh mix. Further increasement of water quantity is necessary to increase the workability of fresh concrete but we usually remain at water quantity 150 – 210 l/m3. The final water/powder ratio (by volume) is 0.85 – 1.10. The required flow ability and other properties of fresh concrete are achieved by wide application of chemical admixtures. Admixtures are materials which are added to concrete in very small quantities (compared to the cement mass) before or during mixing in order to achieve certain properties of fresh or hardened concrete.

2.7 Natural pozzolans

Natural pozzolans have been used for centuries. The term “pozzolan” comes from a volcanic ash mined at Pozzuoli, a village near Naples, Italy, following the 79 AD eruption of Mount Vesuvius. However, the use of volcanic ash and calcined clay dates back to 2000 BC and earlier in other cultures. Many of the Roman, Greek, Indian, and Egyptian pozzolan concrete structures can still be seen today, attesting to the durability of these materials. The North American experience with natural pozzolans dates back to early 20th century public works projects, such as dams, where they were used to control temperature rise in mass concrete and provide cementitious material (Design and Control of Concrete Mixtures,3rd chapter,2000). In addition to controlling heat rise, natural pozzolans were used to improve resistance to sulfate attack and were among the first materials to be found to mitigate alkali-silica reaction. The most common natural pozzolans used today are processed materials, which are heat treated in a kiln and then ground to a fine powder they include calcined clay, calcined shale, and metakaolin.

Figure (2.5): Metakaolin, a calcined clay, (Design and Control of Concrete Mixtures,3rd chapter,2000)

Natural pozzolans, such as calcined shale, calcined clay or metakaolin, are materials that, when used in conjunction with portland or blended cement, contribute to the properties of the hardened concrete through hydraulic or pozzolanic activity or both. A pozzolana is a siliceous or aluminosiliceous material that, in finely divided form and in the presence of moisture, chemically reacts with the calcium hydroxide released by the hydration of portland cement to form calcium silicate hydrate and other cementitious compounds. Pozzolans and slags are generally categorized as supplementary cementitious materials or mineral admixtures. Table(2.3) lists the applicable specifications these materials meet.

Table(2.3):Specifications and Classes of Supplementary Cementitious Materials, (Design and Control of Concrete Mixtures,3rd chapter,2000).

The practice of using supplementary cementitious materials in concrete mixtures has been growing in North America since the 1970s. There are similarities between many of these materials in that most are by products of other industrial processes; their judicious use is desirable not only from the national environmental and energy conservation standpoint but also for the technical benefits they provide concrete. Supplementary cementitious materials are added to concrete as part of the total cementitious system. They may be used in addition to or as a partial replacement of Portland cement or blended cement in concrete, depending on the properties of the materials and the desired effect on concrete. Supplementary cementitious materials are used to improve a particular concrete property, such as resistance to alkali-aggregate reactivity. The optimum amount to use should be established by testing to determine (1) whether the material is indeed improving the property, and (2) the correct dosage rate, as an overdose or underdose can be harmful or not achieve the desired effect. Supplementary cementitious materials also react differently with different cements. Traditionally, fly ash, slag, calcined clay, calcined shale, and silica fume were used in concrete individually. Today, due to improved access to these materials, concrete producers can combine two or more of these materials to optimize concrete properties. Mixtures using three cementitious materials, called ternary mixtures, are becoming more common. Supplementary cementitious materials are used in at least 60% of ready mixed concrete (PCA 2000). ASTM C 311 provides test methods for fly ash and natural pozzolans for use as supplementary cementitious material in concrete.

Figure (2.6): General purpose construction using Pozzolana(left to right)walls for residential buildings, pavements, high-rise towers, and dams(Design and Control of Concrete Mixtures,3rd chapter,2000).

The natural Pozzolanas include the materials that can be ground and used directly without any treatment, such materials include: i. Materials of volcanic origin. ii. Material of sedimentary origin. In Sudan, both natural and artificial Pozzolanas were reported by Whiteman (Whiteman, 1978) and Siyam (Siyam,1987) . The pumice(volcanic origin) was found in the northern part of the Sudan (Bayouda desert), and in the Western part at Marra Mountains. Another source for natural Pozzolana materials is diatomite earth which occurs at Gregrieb area North Wad Madani at the Western bank of the Blue Nile.

2.8 Gum Arabic

Gum Arabic, also known as gum acacia, chaar gund, char goond or meska, is a natural gum made from the sap taken including two types of acacia trees; Acacia Senegal and Acacia Seyal. Gum Arabic is harvested on a commercial scale from wild trees in the Sahel from Senegal to Somalia and Sudan, although it was there in earlier times in some areas of the Arabian Peninsula in the west of Asia [Karamalla, A, Siddig, Osman, (1998)]. Sudan is the largest producer of Gum Arabic in the world which produces 70- 85% of world production, and produces most of Gum Arabic in Sudan from the tree Acacia Senegal (in Arabic: Hashab) is the tree found naturally in the semi- desert in Africa and some areas of Asia and the Sudan is characterized by the presence of the largest belt of Acacia Senegal in the west see Fig (2.7) (Rahim, 2006). .

Figure (2.7): Hashab, (Rahim, 2006).

2.9 Mix proportions

To produce SCC, the major work involves designing an appropriate mix proportion and evaluating the properties of the concrete thus obtained. In practice, SCC in its fresh state shows high fluidity, self-compacting ability and segregation resistance, all of which contribute to reducing the risk of honey combing of concrete. With these good properties, the SCC produced can greatly improve the reliability and durability of the reinforced concrete structures. In addition SCC shows good performance in compressive strength test and can fulfill other construction needs because it has taken into consideration the requirements in the structural design (Subramanian and Chattopadyay 2002). No standard method for determining mixture proportions currently exists for SCC. However, many different proportion limits have been listed in various publications. Multiple guidelines and “rules of thumb” about mixture proportions for SCC have been found (EFNARC,2002) . For example, 1. Okamura and Ozawa (1995) proposed a simple proportioning system assuming general supply from ready-mixed concrete plants.  The coarse and fine aggregate contents are fixed so that self-compactability can be a achieved easily by adjusting the water-power and super plasticizer dosage only.  The coarse aggregate content in concrete is fixed at 50% of the solid volume. The fine aggregate content is fixed at 40% of the mortar volume.  The water-powder ratio in volume assumed as 0.9 to 1.0, depending on the properties of the powder.  The super plasticizer dosage and the final water powder ratio are determined so as to ensure self-compact ability. 2. The “Standardized mix design method of SSC” proposed by the Japan Ready Mix Concrete Asocial, JRMCA (1998) is a simplified version of Okamura and ozawa method. This method can be employed to produce SCC with a large amount of powder materials, and water-binder ratio of < 0.30. 3. Gibbs (1999) states that the following particle rules of thumb for the proportioning of SCC mixture exist.  Coarse aggregate content by weight should be limited to 700-800 kg/m3 (about 30%of the total volume)  Paste not less than 40% of the volume of the mixture.  Low sand content in the mortar (40-50%by volume).  Water/powder ratio not more than 0.5(powder being solids < 0.0035 in, 0.09 mm). 4. A visual Summary of the segregations as listed by Chattopadya (2002) is a follows.  Water : 13.5 to 15% of volume  Powder : 15 to 16.5% of volume  Fine aggregate : 20% of volume  Coarse aggregate : 50% of volume

Table (2.4 ): Typical range of SCC mix composition based on “The European Guidelines for Self Compacting Concrete”.

2.10 Previous Researches Related to Research Problem: Mohja M.Osman (2010) studied the use of Graygreb`s Natural Pozzolana in concrete mix with several different percentage replacements of cement(10%,20%,30%).She found that when replacing pozzolana with cement the compressive strength of concrete will increase depending on the quantity of pozzolan in mixes up to certain percentage then decrease. Her results showed that 10% Graygreb`s Natural Pozzolana replaced with cement gives higher compressive strength than other mixes (20%,30%).

Osman Alsr Osman Dabolk (2010) Undertook a case study of Pozzolana Excavated from the mountain in Bayoda Desert. He tested four mixes with different percentage of Bayoda Desert Pozzolana replacements of cement(0%,10%,20%,30%).Also , he tested other mixes with the same previous percentage of replacement but adding lime Stone with pozzolana. These resulted more compressive strength in concrete mixes than those without adding lime Stone. In all these experimental tests the percentage of 10% replacement gave the highest value of compressive strength in all mixes. The improvement of strength in concrete was large, 20% of extra strength gained in 28 days comparison to the control mix

Ghassan K. Al-Chaar, Mouin Alkadi and Panagiotis G. Asteris(2013) investigated the use of natural pozzolan as a partial cement substitute in concrete materials, four mixes using three types of natural pozzolan, as well as a Class F fly ash, are evaluated. In their study the compressive strength of test specimens (50 mm cubes), cement and sand paste was selected instead of concrete mix to eliminate the variability exhibited by the presence of aggregate. In the test mixtures, mineral admixtures were used to replace 10, 15, 20, 25, 30, and 40% of the mass of the Portland cement used in the control mixture. The results are presented in appendix A1 and A2 . From these experimental tests they found that the percentage of 10% replacement will lead to a better strength development than other percentages.

According to Hajime (Okamura, 1997), a new type of concrete which can be compacted into every corner of a formwork purely by means of its own weight, was proposed by Okamura in 1997. He started a research project on the flowing ability and workability of this special type of concrete, later called SCC. The self- compactability of this concrete was largely affected by the characteristics of materials and the mix proportions. In his study Okamura had fixed the coarse aggregate content to 50% of the solid volume of concrete and the fine aggregate content to 40%of the mortar volume, so that self-compactability could be achieved easily by adjusting the water to cement ratio and superplasticizer dosage only. A model formwork, comprised of two vertical sections (towers) at each end of a horizontal trough, was used by Okamura to observe how well SCC could flow through obstacles.

Appendix (A3) shows the ends of small pipes mounted across the horizontal trough and used as obstacles. The concrete was placed into a right-hand tower, flowed through the obstacles, and rose in the left-hand tower. For the achievement of self- compactability, a superplasticizer was indispensable. With a superplasticizer, the paste can be made more flowable with little concomitant decrease in viscosity, compared to the drastic effect of the water, when the cohesion between the aggregate and the paste is weakened.

After Okamura began his research in 1986, other researchers in Japan have started to investigate SCC, looking to improve its characteristics. One of those was Ozawa (1989) who had done some research independently from Okamura, and in the summer of 1988, he succeeded in developing SCC for the first time. Ozawa completed the first prototype of SCC using materials already on the market. By using different types of superplasticizers, he studied the workability of concrete and developed a concrete which was very workable. Other experiments carried out by Ozawa focused on the influence of mineral admixtures, like fly ash and blast furnace slag, on the flowing ability and segregation resistance of SCC. He found out that the flowing ability of the concrete improved remarkably when Portland cement was partially replaced with fly ash and blast furnace slag. After trying different proportions of admixtures, he concluded that 10-20% of fly ash and 25- 45% of slag cement, by mass, showed the best flowing ability and strength characteristics.

(Khayat,1997), evaluated the uniformity of in situ mechanical properties of SCC used to cast experimental wall elements. Eight optimized SCC mixtures with slump flow values greater than 630 mm and a conventional concrete with a slump of 165 mm were investigated. The SCC mixtures incorporated various combinations of cementitious materials and chemical admixtures. Several trails were obtained in order to evaluate the uniformity of compressive strength and modulus of elasticity along the height of each wall. Khayat found out that all cores from both types of concrete exhibited little variation in compressive strength and modulus of elasticity in relation to height of the wall, indicating a high degree of strength uniformity. However, compressive strength and modulus of elasticity were greater for SCC samples than those obtained from the medium fluidity conventional concrete.

Kemal Celik, Cagla Meral1, Mauricio Mancio, P.K. Mehta, P.J.M. Monteiro(2012),investigated the effects of Portland cement replacement on the strength and durability of SSC by testing two replacement materials high-volume natural pozzolan (HVNP), a Saudi Arabian aluminum-silica rich basaltic glass and high-volume Class-F fly ash (HVFAF), from Jim Bridger Power Plant, Wyoming US. As an extension of the study, limestone (LS) was also used to replace Portland cement, alongside HVNP or HVFAF, forming ternary blends. Along with compressive strength tests, non-steady state chloride migration and gas permeability tests were performed, as durability indicators on SCC specimens. The results were compared to two reference concretes; 100% ordinary Portland cement (OPC) and 85% OPC – 15% LS by mass. The HVNP and HVFAF concrete mixes showed strength and durability results comparable to the reference concretes; identifying that both can effectively be used to produce of low-cost and environmental friendly SCC.The larger amount of NP/FAF addition led to reduced compressive strength compared to the control specimen that have only 15% LS addition. The comparison between FAF and NP among the ternary mixes in appendix (4) shows that 30 mass% NP replacement had higher strength than the 30 mass% FAF replacement, whereas 40% and 50 mass% NP replacement had lower strength than the corresponding FAF replacements.

HafezE.Elyamanya,AbdElmoatyM.AbdElmoatya,BasmaMohamed(2014), sudied the effect of filler types on physical, mechanical and microstructure SCC and Flow-able concrete The objective of their study was to evaluate the effect of various filler types on the fresh and hardened properties of SCC. For this purpose, two groups of fillers were selected. The first group was pozzolanic fillers (silica fume and metakaolin) while the second group was non-pozzolanic fillers (limestone powder, granite dust and marble dust). Cement contents of 400 kg/m3 and 500 kg/m3 were considered while the used filler material was 7.5%, 10% and 15%.there was a good correlation between fresh concrete properties and hardened concrete properties for SCC and Flow-able concrete. Appendix (A4) shows the variation in concrete compressive strength of SCC at the different ages of curing for different types of fillers for concrete mixes with 400 kg/m3 cement content.. The SCC containing 500 kg/m3 cement content shows the same pervious observation as presented in appendix (A5). Further, it is clear that the increase in filler content from 7.5% to 15.0% has not any significant effect on concrete compressive strength for all types of fillers except silica fume. There is a noticeable increase in concrete compressive strength as silica fume content increase. Also, appendix (A6) shows the concrete compressive of flow-concrete at the different ages of curing for different types of fillers for concrete mixes with 400 kg/m3 cement content.

Abdeljaleel, Hassaballa and Mohmed(2012) investigated the use of Gum Arabic from (Hashab) trees in concrete mixes, after crushing to be in a form of powder which was dissolved in water to get the liquid of this additive. In this study, Gum Arabic (G.A.) powder and liquid was added to concrete mixes at ratios 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0 % and 1.2 % of cement content. Fifteen concrete mixes were prepared: One as a control mix, seven with Gum Arabic powder, and seven with Gum Arabic liquid. The study showed that the addition of Gum Arabic to the concrete mixes has a clear effect when equal to 0.4% of cement content. The compressive strength was measured at ages of 7, 21, and 28 days and it was found that it decreases slightly with increase in the proportion of Gum Arabic in concrete mixes. Their paper shows good results of compressive strength and workability of concrete were obtained when using the Gum Arabic liquid. The results of these experiments have been shown in appendix A(7-11) The results of fresh and hardened concrete tests conducted by adding different ratios of the powder and liquid of gum Arabic .Appendix A(8 and 13) show the results of compressive strength and slump test during all ages .From Appendix A(8, 12and 13), the compressive strength values decrease with the increase of the Gum Arabic powder and slump values remain constant in all mixes when adding different ratios of Gum Arabic powder , during all ages, and is thought to be due to the adhesive and bonding properties of this product. Appendix A(9,11,14 and 15) , show the results of compressive strength and slump , from which it is found that there was significant change in the properties of fresh and hardened concrete when adding all ratios of G.A. liquid , during all ages, the compressive strength values decrease with the increase of the G.A . Liquid and slump values increase in all mixes at all ages. Appendix A(16-20) show relation between liquid & powder of .G.A. ratios and compressive strength of concrete at different ages.

Tarig A,Abd Allah(2016) investigated the effect of (Gum Arabic) on fresh and hardened concrete for trying to produce a self-compacting concrete(SCC).Results for trail concrete mixes were analyzed using the European guidelines for self- compacting concrete. The study shows that the values of slump flows increased with the increasing of the dosage of super plasticizer and gum Arabic liquid, the use of super plasticizer and gum Arabic liquid as additive to concrete mixes may result in SCC. The value of compressive strength decreased slightly. When increasing the value of gum Arabic liquid and SP dosage for. Thus it is concluded from this study there is possibility of that the Gum Arabic in liquid state as local additive in the concrete mixes to produce self-compacting concrete provided that another additive that increases or stops the decrease in strength.

2.10.1 Summary of Researchers Finding:

The main points that can be excavated from reviewed researches are:

 10% Replacement of cement volume with Natural Pozzolana in concrete mix produce more compressive strength for concrete . This percentage is the most suitable and effective for Natural Pozzolana in concrete mix than others.  Addition of Gum Arabic decrease concrete compressive strength.  Gum Arabic in liquid state can work as local additive in the concrete mixes to produce SCC.  The possibility of using Natural Pozzolana with Gum Arabic to produce SCC is to be investigated.

CHAPTER THREE

EXPERIMENTAL WORK

3.1 Introduction

This chapter presents the experimental program for mixes and constituent materials used to produce SCC associated with this research work. The laboratory investigation consisted of testing the constituent materials and the mix with both fresh and hardened properties. Fresh concrete was tested to ensure the self- compacting ability of various mixes (mix1,mix2,mix3,mix4,mix5,mix6), slump test to ensure filling ability in the plastic state. The test used for hardened concrete was compressive strength test. The properties of several constituent materials used to produce SCC are also discussed such as unit weight, specific gravity and the grading distribution. Then , the procedure for mix design, the initial calculation of mixes, casting, curing and testing are presented.

3.2 Constituent Material properties

The Constituent materials used to make SCC can have a significant influence on the fresh and hardened characteristics of the SCC. The following sections describe constituent materials used for manufacturing SCC in the laboratory program. Information on the chemical and physical characteristics of the constituent materials and the mixture proportions is also presented.

3.2.1 Portland Cement

Ordinary Sudanese Portland Cement PC 42.5 manufactured by mass was used conforming to EN 197-1. The physical properties and the chemical composition of the cement used throughout the tests are presented in the Tables (3.1) and (3.2) .

Table (3.1): Chemical composition of the cement

Determined as EN 197-1 Oxide (%) Limits CaO 61.94 -

SiO2 18.08 -

Al2O3 5.58 -

Fe2O3 2.43 - MgO 2.43 max. 6.0%

SO3 2.93 max 3.5%

K2O 0.99 -

Na2O 0.18 -

Table (3.2): Physical properties of the mass cement Result Specification Physical property obtained EN 197-1 Vicat initial setting time (minutes) 132 `≥30 Vicat final setting time (minutes) 208 ≤600 Compressive strength 3- day 37 MPa ≥22.0 MPa Compressive strength 28- day 46 MPa ≥43.0 MPa Specific gravity 3.15 -

3.2.2 Coarse aggregates:

20mm maximum diameter rounded coarse aggregate was used. The specific gravity and water absorption of the coarse aggregate are 2.65 and 0.8% respectively. The properties of coarse aggregate are presented in Table (3.3).The gradation of the coarse aggregate was determined by sieve analysis as per BS 882 and is presented in Table (3.4) .

Table (3.3) Properties of the coarse aggregate Properties Determined as Specific gravity 2.65 Bulk density (kg/m3) 1610

Table (3.4): Sieve Analysis of coarse aggregate %Cumulative %Cumulative BS Sieve Retained retain by passing by 882 size(mm) weight(g) weight weight Limits 85- 20 60 0.78 99.22 100 14 4180 55 45 5-70 10 6232 82 18 0-25 5 7372 97 3 0-5

2.36 7600 100 0 0-5

3.2.3 Fine aggregates

The fine aggregate used in the experimental program was natural river sand. The specific gravity and absorption of the sand is presented in Table (3.5). The gradation of the aggregate was determined by sieve analysis and is presented in Table (3.6).

Table (3.5): Properties of the fine aggregate Properties Determined as Specific gravity 2.65 Bulk density (Kg/m3) 1692

Table (3.6) Sieve analysis of fine aggregate Total %retained %passing BS882 Sieve size(mm) retained by weight by weight limits weight(g) 10 0 0 100 100 5 59.06 8.76 91.24 89-100 2.36 170.18 25.23 74.77 60-100 1.18 345.27 51.18 48.82 30-100 600 517.04 76.65 23.35 15-100 300 624.47 92.57 7.43 5-70 150 674.56 100 0 0-15

3.2.4 Natural Pozzolana

Local Natural Pozzolana from Bayouda desert was used in this experimental work. The chemical analysis of the Pozzolana is shown in Appendix (C1).The specimen of this Pozzlana was collected by Yara For Cement Solutions Company.

Figure (3.1): Bayouda Natural Pozzolana

3.2.5 Liquid Gum Arabic

Liquid Gum Arabic used in this experimental work was brought from Gum Arabic Company Ltd as a powder, then mixed with water for at least 24 hours.

3.3 Mix design

There is no standard method for SCC mix design and many academic institutions, admixture, ready-mixed, precast and contracting companies have developed their own mix proportioning methods.Mix designs often use volume as a key parameter because of the importance of the need to over fill the voids between the aggregate particles. Some methods try to fit available constituents to an optimized grading envelope. Another method is to evaluate and optimize the flow and stability of first the paste and then the mortar fractions before the coarse aggregate is added and the whole SCC mix tested. Laboratory trials should be used to verify properties of the initial mix composition with respect to the specified characteristics and classes. If necessary, adjustments to the mix composition should then be made. Once all requirements are fulfilled, the mix should be tested at full scale in the concrete plant and if necessary at site to verify both the fresh and hardened properties. The mix design is generally based on the approach outlined below(EFNARC, 2002). : • Evaluate the water demand and optimize the flow and stability of the paste • Determine the proportion of sand and the dose of admixture to give the required robustness • Test the sensitivity for small variations in quantities (the robustness) • Add an appropriate amount of coarse aggregate • Produce the fresh SCC in the laboratory mixer, perform the required tests • Test the properties of the SCC in the hardened state • Produce trial mixes in the plant mixer.

Fig.(3.2):Mix design procedure flow chart, (EFNARC, 2002).

In SCC mix design, required quantity of individual concrete components is defined. In addition, it is necessary to achieve the following: • The paste carries the aggregate grains. Therefore the paste volume has to be greater than the volume of voids between the aggregate grains. Each individual aggregate grain has to be fully coated and lubricated by a layer of paste. Thus the fluidity is increased and the friction between aggregate grains is reduced. • Fluidity and viscosity of the paste have to be controlled and balanced by the choice and ratio of cement and admixtures. •Replacement 10% of cement by Natural Pozzolana in order to control concrete shrinkage and temperature during the hydration process and increasing the final strength of concrete. • The coarse aggregate grains must be full surrounded by mortar. This reduces coarse aggregate interlock when the concrete passes through narrow openings in forms or gaps between reinforcement. The quantity of coarse aggregate in SCC is always reduced. As a result, concretes having the following in comparison to vibrated concretes are obtained: • Lower coarse aggregate content with limited nominal maximum grain up to 20 mm. • Greater total quantity of fines, lower than 0.125 mm (cement, active and inert mineral additions and finest aggregate particles), • Increased paste content. • Lower water/powder ratio, and adding Gum Arabic in order to obtain the required properties of concrete in fresh and hardened state (Abdeljaleel, Hassaballa and Mohmed,2012). It is necessary to define the mix design method (procedure). The best known is the Method of mix design by Okamura, in 6 steps. The properties of concrete mix thus specified must be confirmed by laboratory testing in each step and corrected if necessary. Mixing procedure for SCC according shown in (Figure 3.2) is described as follows:

1. Binder and aggregate were mixed for one minute.

2. (70%) of water was added and mixed for two minutes.

3. Liquid Gum Arabic with the (30%) of water was added and mixed for two minutes.

4. The mix was stopped and kept rest for 2 minutes.

5. The mix was remixed for one minute and discharged for SCC tests. . Procedure for SCC mix design

An example of a procedure for efficiently designing SCC mixes is shown below. It is based on a method developed by Okamura. The sequence is determined as :

A ) Definition of desired air content

Air content may generally be set at 2 per cent, or a higher value specified when freeze thaw resistant concrete is to be designed.

B ) Determination of coarse aggregate volume:

Coarse aggregate volume is defined by bulk density. Generally coarse aggregate content (D> 4 mm)should be between 50 per cent and 60 per cent. When the volume of coarse aggregate in concrete exceeds a certain limit, the opportunity for collision or contact between coarse aggregate particles increases rapidly and there is an increased risk of blockage when the concrete passes through spaces between steel bars. The optimum coarse aggregate content depends on the following parameters :Maximum aggregate size. The lower the maximum aggregate size, the higher the proportion of coarse aggregate.· Crushed or rounded aggregates. For rounded aggregates, a higher content can be used than for crushed aggregates.

C) Determination of sand content:

Sand, in the context of this mix composition procedure is defined as all particles larger than 0.125 mm and smaller than 4 mm. Sand content is defined by bulk density. The optimal volume content of sand in the mortar varies between 40 – 50 % depending on paste properties.

D) Design of paste composition

Paste > 40 % of the volume of the mix E) Determination of optimum volumetric water/powder ratio.

F) Concrete tests

The concrete composition is now determined and ready for concrete tests.

3.4 Casting, curing and testing

Before casting the fresh properties of SCC such as slump flow and T50 tests were conducted to characterize the workability of the fresh concrete to access filling abilities. During the slump flow test, the time required for SCC to reach 500mm length slump flow radius (T50) and the final diameter of the concrete circle through two directions were measured. Specimens (cubes) were then casted in steel moulds and were not subjected to any compaction other than their own self weights. After the specimens hardened, the moulds were removed and they were placed in the water for curing. After 7,14 and 28 days curing, the robustness of the specimens was determined.

3.5 Calculation of initial key proportions

The detailed steps for calculation of key proportions are presented below based on EFNARC method:

SCC mix with 28% coarse aggregate content of concrete volume was designed for water/ binder ratio 0.45(by weight). Coarse aggregate of size max 20mm was used in this mix. Air content was assumed as 2% of concrete volume.

3.5.1 Calculation of Coarse Aggregate Content in Concrete Volume

Specific gravity of Aggregate = 2.65

Density of coarse aggregate =1610 kg/m3 Coarse aggregate weight = 1610*(45.4/100) = 731kg/m3

Coarse aggregate volume =731/2.65

=275.85 liter/m3

3.5.2 Calculation of Mortar Volume

Mortar Volume = Concrete volume-coarse aggregate volume

= 1000-275.85=724.15liter/m3

3.5.3 Calculation of Sand Volume

% of sand in Mortar volume = 45.7

Sand Volume = 724.15*(45.7/100) = 331 liter/m3

3.5.4 Calculation of Paste Volume

Cement Paste Volume = Mortar volume-sand volume

= 724.15-331= 393.15 liter/m3

3.5.5 Calculation of Cement Paste Composition

Specific gravity of cement = 3.15

Air content (assumed) = 2% = 20 liter/m3

Water/ binder ratio (by weight) = 0.45

Binder = 500 kg/m3

Cement = 450kg/m3 Water = 500*0.45 = 225 liter/m3

Volume of binder = 500/3.15 = 158.73liter/m3

Total Paste volume

: Volume of (binder +Water +Air)

158.73+225+20=403.7litre/m3

3.5.6 Calculation of Constituent Materials for Concrete

Cement = 450 kg/m3

Initial water content = 225 liter/m3

Coarse aggregate = 730 kg/m3

Sand

: 331*2.65 = 877 kg/m3

Pozzolana 10% of cement = 50 kg/m3

These constituent material of mixes shown are shown in Table (3.7).

Table (3.7 ): Constituent Materials of mixes

Binder Cement Pozzolana water Coarse aggregate sand kg/m3 kg/m3 kg/m3 kg/m3 kg/m3 kg/m3

500 450 50 225 730 877

3.6 TEST METHODS

The slump flow test is used to assess the horizontal free flow and filling ability of SCC in the absence of obstructions. The test also indicates resistance to segregation. On lifting the slump cone, filled with concrete the average diameter spread of the concrete is measured. It indicates the filling ability of the concrete. Slump flow test apparatus is shown in Figures(3.3)and (3.4). Slump cone has 20 cm bottom diameter, 10 cm top diameter and 30 cm in height. In this test, the slump cone mould is placed exactly on the 20 cm diameter graduated circle marked on the plate, filled with concrete and lifted upwards. The subsequent diameter of the concrete spread is measured in two perpendicular directions and the average of the diameters is reported as the spread of the concrete. T50cm is the time measured from lifting the cone to the concrete reaching a diameter of 50 cm. The measured T50cm indicates the deformation rate or viscosity of the concrete. This test is used along with slump flow test to assess the flowability of SCC. T50cm test apparatus is shown in Figures(3.3)and (3.5). The slump flow is used to assess the horizontal free flow and the of SCC in the absence of obstructions.

Figure (3.3): Slump flow test and T500 time test(EFNARC, 2002) .

This is a fast, simple method which is most frequently used both in laboratories and in Construction sites. It gives a good assessment of deformability (flow ability of fresh concrete) and can give visual information on stability. It is necessary and obligatory to define the slump flow class, SF, as the basic characteristic of fresh concrete mix, in the concrete design. Three classes are proposed and the mark is derived as an acronym from the name of the test in the English language: Application of concrete according to the introduced classes: SF1 can be applied in: - Slightly or non-reinforced concrete structures that are cast from the top with free spread from the delivery point (for example, floor structure slabs), - Pumped concretes, - Sections of structures that are sufficiently small to prevent larger horizontal flow (piles and some sections of foundations). SF2 can be applied in majority of normal structures (walls and columns). SF3 is usually applied in concrete with maximal aggregate grain size less than 16 mm, in elements with congested reinforcement, in structures with complex shapes of forms, if the forms are filled from below. SF3 class gives better surface finish than SF2 when the fresh concrete is placed normally vertically but the risks of segregation are higher. In special cases self-compacting concretes with flow diameter greater than 850 mm can be required but then special care should be taken of control of all forms of segregation. In that case maximum grain of coarse aggregate should be less than 12 mm. In case time required to reach the spread concrete diameter of 500 mm is measured, viscosity of the fresh mix can also be controlled. The planned classification is given in Table(3.8 ).

Table (3.8 ): Slump flow classification (EFNARC, 2002).

Concrete class Slump flow Criteria (mm) specified

SF1 550-650 520mm ≤ ds ≤ 700mm

SF2 660-750 640mm ≤ ds ≤ 800mm

SF3 760-850 740mm ≤ ds ≤ 900mm Stated value of spread

concrete diameter ds ds ± 80mm

Figure (3.4): Slump flow test

Figure (3.5): T500 time test.

CHAPTER FOUR

ANALYSIS AND DISCUSSION OF LABORATORY TEST RESULTS

4.1 Introduction

This chapter presents the results obtained from the testing program and discusses the effect of the local additive (Natural Pozzolana and Gum Arabic) in concrete mix. The results were obtained from the slump flow test and T500 test and compression test.

Six different percentage of Gum Arabic were tested (0.00, 1.5 ,2 ,3 ,7 and 10)%. The mixes along side with control mix without additive were tested to investigate the role of Gum as a viscosity modifying agent and its affect in concrete strength.

Comparison between these results and The European Guidelines for Self- Compacting Concrete standard and limits was used to check the properties of mixes and determine the optimum percentage of additives .

4.2 Tests Result

The result obtained by conducting the test methods on the fresh mixes and hardened concrete are shown in tables as follows:

 Table 4.1 contain the results for the control mix.  Table 4.2 presents the results for mix(1) with 10% Pozzolana and 0.0% Gum Arabic.  Table 4.3 presents the results for mix(2) with 10% Pozzolana and 1.5% Gum Arabic.  Table 4.4 presents the results for mix(3) with 10% Pozzolana and 2.0% Gum Arabic.  Table 4.5 presents the results for mix(4) with 10% Pozzolana and 3.0% Gum Arabic.  Table 4.6 presents the results for mix(5) with 10% Pozzolana and 7.0% Gum Arabic.  Table 4.7 presents the results for mix(6) with 10% Pozzolana and 10.0% Gum Arabic.

 Average for results of compressive strength , slump and T500 time tests are shown in Table (4.8).

Table (4.1) : Control mix ,without additive.

Age Area Slump Failure Compressive Average Load Strength Compressive (Day) (mm2) (mm) (N/mm2) Strength (KN) (N/mm2) 517.5 23 24.17

562.5 25 7 551 24.5

697.5 31 30.33 22500 60

630 28 14 720 32

799 35.5 36.5

855 38 28 810 36

Table (4.2): Mix (1) 10% Replacement cement with pozzolana & 0.00% G.A added.

Age Area Slump Failure Compressive Average Load Strength Compressive (Day) (mm2) (mm) (N/mm2) Strength (KN) (N/mm2) 675 30

756 33.6 7 32.24 745 33.11

878 39 41.5 22500 90

957 42.50 14 970 43

950 42 45

1080 48 28 1035 46

Table (4.3): Mix (2) 10% Replacement cement with pozzolana & 1.5% G.A added.

Age Area Slump Failure Compressive Average Load Strength Compressive (Day) (mm2) (mm) (N/mm2) Strength (KN) (N/mm2) 661.5 29.4 30.29

725.5 32.24 7 658 29.24 22500 150 832.5 37 36.28

799.0 35.5 14 817.9 36.35

945 42 42.27

967.5 43 28 940.5 41.8

Table (4.4): Mix (3) 10% Replacement cement with pozzolana & 2.0% G.A added.

Age Area Slump Failure Compressive Average Load Strength Compressive (Day) (mm2) (mm) (N/mm2) Strength (KN) (N/mm2) 630 28 28.66

616 27.38 7 688.5 30.6 22500 220 765.0 34 34

787.5 35 14 742.5 33

945 42 40

880 39.11 28 855 38

Table (4.5): Mix (4) 10% Replacement cement with pozzolana & 3.0% G.A added.

Age Area Slump Failure Compressive Average Load Strength Compressive (Day) (mm2) (mm) (N/mm2) Strength (KN) (N/mm2) 520 23.11 23.62

528 23.45 7 549.7 24.3

652.5 29 30.17

22500 570 697.5 31 14 686.5 30.5

750 33.33 34.22

775 34.44 28 785 34.9

Table (4.6):Mix (5) 10% Replacement cement with pozzolana & 7.0% G.A added.

Age Area Slump Failure Compressive Average Load Strength Compressive (Day) (mm2) (mm) (N/mm2) Strength (KN) (N/mm2) 202.5 9 10.2

259 11.51 7 227 10.1 22500 560 349 15.5 14.33

315 14 14 304 13.5

410.3 18.24 16.62

370.6 16.47 28 337.5 15

Table (4.7): Mix(6) 10% Replacement cement with pozzolana & 10% G.A added.

Age Area Slump Failure Compressive Average Load Strength Compressive (Day) (mm2) (mm) (N/mm2) Strength (KN) (N/mm2) 75 3.33 2.96

57 2.53 7 68 3.02 22500 555 126 5.6 5.63

117 5.2 14 137 6.1

148.5 6.6 6.33

130 5.7 28 152.5 6.7

Table (4.8): Average for results of compressive strength and slump, T500 time tests.

G.A Average Average Average Slump T500 time Compressive Compressive Compressive Strength Strength Strength 2 2 2 (%) (N/mm ) (N/mm ) (N/mm ) (mm) (sec) 7days 14days 28days 0.00 32.24 41.5 45 90 ------

1.5 30.29 36.28 42.27 150 ------

2.0 28.66 34 40 220 ------

3.0 23.62 30.17 34.22 570 2.2

7.0 10.2 14.33 16.62 560 2.7

10 2.96 5.63 6.33 555 3.4

4.3 Analysis of fresh SCC properties test results

The slump-flow and T500 time are tests to assess the flowability and the flow rate of self-compacting concrete in the absence of obstructions. The slump-flow is based on the slump test described in EN 12350-2. The result is an indication of the filling ability of self-compacting concrete. The T500 time is also a measure of the speed of flow and hence the viscosity of the self-compacting concrete.

4.3.1 Effect of Gum Arabic in the slump flow test Gum Arabic has a marked effect on flowability and workability of concrete. Increasing the percentage of Gum in the mix produce more flowability and workability.

For more than 3% the effect of Gum becomes almost constant and the slump start to decrease slowly with rising the percentage of Gum in concrete. That is due to the considerable cohesion which is formed in the mix when containing a high percentage of Gum (mix5,mix6). Hence Figure(4.1) summarizes the effect of Gum Arabic on slump flow.

600

500

400

Slump(mm) 300 570 560 555

200

220 100 150 90 0 0.00% G.A 1.5% G.A 2% G.A 3% G.A 7% G.A 10% G.A

Figure(4.1): Effect of Gum Arabic on slump

For mixes 1,2,3 which contained 0.00%,1.5%,2.0% of Gum Arabic respectivly the slump was measured as anormal slump test , reading the distance betweenn the top of concrete and the top of the standard cone.So these mixes did not match the standard and limits of The European Guidelines for Self-Compacting Concrete .

Mixes 4,5,6 which contained 3.0%,7.0%,10% % of Gum Arabic respectivly show a good range of slump flow and match the standard and limits of The European Guidelines for Self-Compacting Concrete.

4.3.2 Effect of Gum Arabic in the T500 time test

This test was conducted on three mixes only (4,5,6)since these only meet the European Guidelines for Self-Compacting Concrete standard and limits. Mixes contain a high percentage of Gum Arabic (mix5,mix6) had a lower flow speed comparision to mix1, that is due to extensive cohesion and consistanicy which formed in these mixes.That makes the paste slow and limit the viscosity noticeably which means increasing of filling time ability.Figure( 4.2) describes this situation clearly.

3.5

3

2.5

2 Time(sc) 3.4 1.5 2.7 2.2 1

0.5

0 3.0% G.A 7.0% G.A 10% G.A

Figure(4.2): Effect of Gum Arabic in T500 time test

4.4 Analysis of hardened SCC properties test results

Compressive strength of concrete is a key parameter which indicates the quality of concrete in hardened state. In order to study the quality of SCC in hardened state, along with other important parameters, compressive strength of SCC mixes was measured using (150×150×150 mm cubes) tests.

For each of the six different mixes prepared a total of 9 concrete cube specimens, 150 mm in size, were cast for determining the compressive strength after 7, 14 and 28 days of water curing. The casting of cubes was made without vibration as required for SCC. The compressive strength of all the mixes after 7, 14 and 28 days curing are shown in Table (4.8).

4.4.1 Effect of Natural Pozzolana in Concrete Compressive strength

Results obtained from cubes tests prove the influence of Bayouda Natural Pozzolana in concrete mix . The Compressive strength was raised by 18.9% on replacement of 10% of cement by pozzolna in concrete mix as shown in Figure (4.3).

45 40 35 30 Compressive strength 25 45 N/mm2 20 36.5 15 10 5 0 Control mix mix (1)

Figure(4.3): Effect of Bayouda Natural Pozzolana in Concrete Compressive strength. 4.4.2 Effect of Gum Arabic in the cubes compressive strength

As can be clearly seen from Figure(4.4) increasing the percentage of Gum Arabic in mixes lead to reducing the strength of SCC.

45 45 42.27 Compressive 40 strength 40 36.5 N/mm2 34.22 35 30 7 days 25 14 days 20 16.62 28 days 15 10 6.33 5 0 0.00% 1.5% G.A 2.0% G.A 3.0% G.A 7.0% G.A 10% G.A control G.A mix

Figure(4.4): Effect of G.A in cubes compressive strength

For the first four mixes (1,2,3,4) which contained (0.00%,1.5%,2.0%,3.0%) of Gum Arabic respectively there was a small change in concrete strenght from each mix to another,but on comparing mix (1) with mix (4) the loss in strength is large as can be seen from Table (4.9) .

Table (4.9): Reduction of compressive strength in mixes

Mix Average Compressive Reduction of Compressive Strength Compressive Strength Strength Comparison to Comparison to mix (1) (N/mm2) control mix % difference 28days % difference control 36.5 ------

1 45 +18.9 ------

2 42.27 +13.65 -6.067

3 40 +8.75 -11.11

4 34.22 -7.0 -23.96

5 16.62 -54.4 -63.067

6 6.33 -82.66 -85.93

Mixes (5 and 6) have very little compressive Strength that makes these mixes very weak and not suitable to be utilized in any construction projects.

During the curing phase it was noticed that mixes (5 and 6) resulted some type of segregation to the concrete cubes, this may be the cause of the very low compressive Strength. Figures (4.5 and 4.6) describes this situation clearly. According to slump and compressive strength results which compared to The European Guidelines for Self-Compacting Concrete standard and limits , mix4 had best results to make Self Compacting Concrete.

Figure(4.5): Segregation in mix (5) cubes.

Figure(4.6) Segregation in mix (6) cubes.

CHAPTER FIVE CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusions

From the investigation, the following conclusions can be drawn:

 In all mixes there weren’t any noticeable segregation in the fresh concrete and there was a homogenous form. Accordingly, in order to avoid any segregation the W/C ratio has to be equal or less than 0.45.  Increasing the percentage of Gum in the mix produce more flowability and workability (slump flow for Mix(4 ) equal 570mm).  For more than 3% of added Liquid Gum the effect in flowability and workability still almost constant and start to decrease slowly when rising the percentage of Gum in concrete.  Increasing the percentage of Liquid Gum more than 3% in the mix cause

decreasing in concrete flow speed (from 2.2 second in Mix(4) T500 test to 2.7 second in Mix(5)) due to extensive cohesion and consistanicy.  10% replacement of cement by Bayouda Natural Pozzolana increase the Compressive strength of mix by 18.9%.  Bayouda Natural Pozzolana slightly increase the flowability and workability in concrete mixes (slump from 60mm in control mix to 90mm in Mix(1)).  Increasing the percentage of Liquid Gum Arabic in mixes leads to reducing the Compressive strength of Self Compacting Concrete (from 40 N/mm2 in Mix(3) to 34.22 N/mm2 in Mix(3)).  When adding Gum Arabic with percentage 7% and more the Compressive strength in mix becomes very low and the concrete will not be suitable to be utilized in any construction projects(Mix(6) compressive strength equal 6.33 N/mm2) .  Segregation in concrete occurred during the curing phase in mixes contained high Liquid Gum Arabic percentage (7% and more ) .  3% Gum Arabic with 10% Natural Pozzolana replacement results in produce of Self Compacting Concrete that satisfy the European Guidelines for Self Compacting Concrete.

5.2 Recommendations The following recommendations are proposed for further research in producing of SCC:

 Use of another additive with Pozzolana like (limestone) to increase the compressive strength.  Decreasing W/C ratio with increasing percentage of Gum Arabic to improve the Compressive strength of concrete .  Conducting tests other than compressive strength that are applied to hardened concrete like splitting tensile strength, and flexural strength to check different types of load influence.  Investigating more percentages of added Liquid Gum Arabic between (2% to 4%) to get better compressive strength .  Investigating the absorption of concrete due to adding Liquid Gum Arabic.  Long time effect should be investigated for this type of SCC mix.

From the results obtained it is recommended to:  Use 3% Gum Arabic with 10% Natural Pozzolana replacement to produce SCC.  Avoid the use of Gum Arabic more than 3% if the w/c ratio is 0.45% due to the low acceptable compressive strength required.

References:

1. [IEA] & [WBCSD], 2009, “Cement Technology Roadmap 2 - Carbon emissions reductions up to 2050 [Online]”. Available: http://www.iea.org/papers/2009/Cement_Roadmap.pdf [Accessed May 11 2010]. 2. ASTM 2007. C192/C192M – 07, “ Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory1”. Safety Precautions, Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards. ASTM. 3. ASTM 2009, C1611/C1611M – 09b, “Standard Test Method for Slump Flow of Self-Consolidating Concrete. ASTM”. 4. MEHTA, P. K. 2001, “Reducing the Environmental Impact of Concrete”, Concrete International, 23, PP.61-66. 5. MEHTA, P. K. 2009, “Global Concrete Industry Sustainability: Tools for Moving Forward to Cut Carbon Emissions”, Concrete International, PP.45- 48. 6. MEHTA, P. K. & MONTEIRO, P. J. M. 2006, “Concrete: Microstructure, Properties, and Materials”, USA, McGraw-Hill. 7. WBCSD 2009, “The Cement Sustainability Initiative: Recycling Concrete”, In: KLEE, H. (ed.). Geneva, Switzerland: World Council for Sustainable Business Development. 8. Krishna Murthy.N., NarasimhaRao.A.V., Ramana Reddy,I.V. and Vijayasekhar Reddy M(September2012) ,” Mix Design procedure for Self- Compacting Concrete”, IOSR Journal of Engineering(IOSRJEN, Volume 2,Issue 9, P.P 33-41. 9. International symposium 1999 on Self-Compacting Concrete, Stockholm, P.P 345-359. 10. Bartos, J. M. (2000),”Measurement of Key Properties of fresh self- compacting concrete”. 11. Okamura, H. (1997). ("Self-Compacting High-Performance Concrete.") Concrete International: P.P 50-54. 12. Ozawa, K. (1989), (“Development of high performance concrete based on the durability design of concrete structures”), EASEC-2, Vol. 1, pp.445-450. 13. Ruža Okrajnov-Bajić and Dejan Vasović, 20 September 2009 , “SELF- Compacting Concrete And Its Application In Contemporary Architectural Practice”, SPATIUM International Review, p.p 28-34. 14. Petersson Ö. et al. (1996): a "MODEL FOR SELF–COMPACTING CONCRETE", Proceedings of International RILEM Conference on ‘Production Methods and Workability of Concrete’, Paisley, pp.483–490. 15. EFNARC, February 2002 , “Specification and guidelines for Self Compacting Concrete”‖,www.efnarc.org. 16. Siyam, A. M. A. 1987, “ Pozzolana Stabiized Blocks for low Cost Housing”, M. Sc.thesis, BRRI, U. of K. 17. Whiteman, A. J. Oxford (1978) Clarendon Press,“The Geology of the Sudan Republic”. 18. Rahim, A.H. (2006),” Economic Analysis of Deforestation: the Case of the Gum Arabic Belt in Sudan”, PhD thesis, Wageningen University. 19. Subramanian, S. and D. Chattopadhyay (2002) , (“Experiments for mix proportioning of self-compacting concrete”), The Indian Concrete Journal, pp.13-20 (2002). 20. JRMCA Tokyo, 1998 , "Manual of Producing High Fluidity (Self- Compacting) Concrete". 21. J.C Gibbs, W.Zhu 1999 ,”Strength of hardened self-compacting concrete”,International RILEM on self-compacting concrete Stockholm, Sweden. 22. Khayat, K.H., Manai K. , A. Trudel(1997) , (“In situ mechanical properties of wall elements cast using self-consolidating concrete”), ACI Materials Journal, pp.491-500 . 23. Kemal Celik, Cagla Meral, Mauricio Mancio, P.K. Mehta, P.J.M. Monteiro 2012, “A Comparative Study Of Self-Consolidating Concretes Incorporating High-Volumn Natural Pozzolana Or High-Volume Fly Ash”, International journal. 24. Ghassan K. Al-Chaar, Mouin Alkadi and Panagiotis G. Asteris ,2013, “Natural pozzolan as a partial cement substitute in concrete” ,The open construction and building technology journal. 25. HafezE.Elyamanya,AbdElmoatyM.AbdElmoatya,BasmaMohamed ,2014, “Effect of filler types on physical, mechanical and microstructure SCC and Flow-able concrete “ , Alexandria engineering journal. 26. Mohja M.Osman 2010 , use of Graygreb`s Natural Pozzolana in Concrete Mix, MSc thesis. College of Engineering, SudanUniversity of Science and Technology. 27. Osman Alsr Osman Dabolk 2010 , “Study about use of Pozzolana in concrete A Case Study of Pozzolana Excavated from the Mountain in Bayod Desert”, MSc thesis. College of Engineering, SudanUniversity of Science and Technology. 28. Abdeljaleel,N,S.,Hassaballa,A,E.,and Mohamed,A,E.,[ 2012],”( Effect of gum Arabic Powder and Liquid on the Properties of Fresh and Hardened Concrete)”.International Journal of Engineering Invention, volume .1, Issue. 12,PP.57-65. 29. Trig A. Abd Allah, 2016 ,”(Investigation of the Effect of Gum Arabic on the Production of Self Compacting Concrete)”, MSc thesis. College of Engineering, SudanUniversity of Science and Technology. 30. Design and Control of Concrete Mixtures,2000 PCA, Portland Cement Association, published book on concrete mixture , proportioning concrete mixtures and placing concrete.

Another resources:

 "SPECIFICATION AND GUIDELINES FOR SELF– COMPACTING CONCRETE", EFNARC, Farnham, UK, February2002,http://www.efnarc.org/pdf/SandGforSCC.PDF

 "THE EUROPEAN GUIDELINES FOR SELF–COMPACTING CONCRETE", BIBM, CEMBUREAU, ERMCO, EFCA, EFNARC, May 2005,http://www.efnarc.org/pdf/SCCGuidelinesMay2 005.pdf

 Burj Dubai 2007, http://www.burjdubai.com/

 Arlanda Airport2003, http://en.wikipedia.org/wiki/File:Arlanda_Flightower.jpg

 MAXXI 2009, http://www.maxxi.parc.beniculturali.it/english/museo.htm Appendices

Appendix (A):

Appendix (A1): Effect of replacement cement with Natural pozzolan from Saudi Arabia on strength development.

Appendix (A2): Effect of cement replacement with Natural pozzolan from South Africa on strength development.

Appendix (A1): Small pipes used as obstacles in formwork (Okamura, 1997).

Appendix (A4): Concrete compressive strength for SCC with 400 kg/m3 cement content.

Appendix (A5): Concrete compressive strength for SCC with 500 kg/m3 cement content and 10% filler content.

Appendix (A6): Concrete compressive strength for Flow-able concrete with 400 kg/m3 cement content.

Appendix (A7): Results of slump and compressive strength tests of the control mix using (0.0 % of Gum Arabic) .

Appendix (A8): Results of compressive strength of concrete mixes containing 0.2% of Gum Arabic powder .

Appendix (A9): Results of compressive strength of the concrete mixes containing 0.6% of Gum Arabic liquid.

Appendix (A10): Average for results of compressive strengths and slump tests (% G.A powder).

Appendix (A11): Average for results of compressive strengths and slump tests ((% G.A liquid).

Appendix (A12): Relation between .G.A. powder ratios and compressive strength of concrete at ages of 7, 21, and 28 days.

Appendix (A13): Relation between powder of .G.A. ratios and slump tests of fresh concrete.

Appendix (A14): Relation between G.A liquid ratios and compressive strength of concrete at ages of 7, 21, and 28 days.

Appendix (A15): Relation between liquid of G.A. ratios and slump tests of fresh concrete.

Appendix (A16): Relation between liquid and powder of G.A. ratios and compressive strength of concrete at age of 7 days.

Appendix (A17): Relation between liquid and powder of G.A. ratios and compressive strength of concrete at age of 21 days.

Appendix (A18): Relation between liquid and powder of G.A. ratios and compressive strength of concrete at age of 28 days.

Appendix (A19): Relation between liquid and powder of G.A. ratios (0.4%, 0.6% and 0.8 %) and compressive strength of concrete at age of 28 days.

Appendix (A20): Relation between powder and liquid of G.A. ratios and compressive strength of concrete at ages of 7, 21, and 28 days.

Appendix (B):

Appendix (B1):Compressive strength machine .

Appendix (B2):Mix2 cubes test.

Appendix (B3): Mix5 cube specimen. Appendix (C):

Appendix (C1): The chemical analysis of the Bayouda Natural Pozzolana.

Appendix (C2): Concrete mix design for Control Mix.