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CHARACTERIZATION OF POZZOLANIC PROPERTIES OF

WASTE GLASS AS PARTIAL REPLACEMENT OF CEMENT

Characterization of Pozzolanic Properties of Waste Glass as Partial

Replacement of Cement

Nafisa Tamanna

Master of Engineering

(Civil Engineering)

2015

CHARACTERIZATION OF POZZOLANIC PROPERTIES OF WASTE

GLASS AS PARTIAL REPLACEMENT OF CEMENT

NAFISA TAMANNA

A thesis submitted

In fulfillment of the requirement for the degree of

Master of Engineering

(Civil Engineering)

Department of Civil Engineering

Faculty of Engineering

Universiti Malaysia Sarawak

2015

i

AUTHOR’S DECLARATION

This is to certify that the dissertation work entitled “Characterization of Pozzolanic

Properties of Waste Glass as Partial Replacement of Cement” has been done by the candidate

herself and does not contain any material extracted from elsewhere or from a work published by

anybody else. The work for this dissertation has not been submitted elsewhere by the author for

any degree. This is a true copy of the thesis, including any required final revisions, as accepted

by the examiners.

Nafisa Tamanna

Matric Number: 13020081

Department of Civil Engineering

Faculty of Engineering

Universiti Malaysia Sarawak

ii

ACKNOWLEDGEMENTS

First of all, Praise to ALLAH for giving me the strength, blessings and the patience to

complete this work successfully. I would like to express my sincere gratitude and appreciation to

my supervisor Dr. Norsuzailina Mohamed Sutan for her trust, guidance, help and encouragement

as well as financial support throughout the research. I would also like to appreciate the guidance

and invaluable co-operation provided by Dr. Delsey Teo Ching Lee and Ibrahim Yakub. I also

would like to thank the technicians in Civil Engineering Department, Chemical Engineering

Department, Mechanical Engineering Department and Faculty of Resource Science especially

Mr. Adha, Mr. Airul, Mr. Sabariman and Mr. Safri at Universiti Malaysia Sarawak. I would also

like to show my appreciation some of the graduate and post graduate students who have provided

invaluable support to me in my research work.

I also would like to acknowledge the financial support of Fundamental Research Grant

Scheme (FRGS) and UNIMAS postgraduate scholarship (Zamalah) during my research.

Last but not least, I wish to express my deep gratitude and sincere appreciation to my

beloved parents, family members and friends for their significant support. Without their support

and appreciations I would have not been able to complete this thesis.

Nafisa Tamanna

2015

iii

ABSTRACT

In recent years, the use of waste glass powder as a partial replacement of cement has introduced widely to reduce the amount of waste glass from the environment. Utilization of waste glass as cement replacement can contribute to reduce cement production that creates a greenhouse effect so that it can cut down the increasing environment pressure. The aims of this thesis were to investigate the pozzolanic characteristics of hardened cement paste inclusion with glass powder and the mechanical strength properties of mortar when cement is partially replaced with various sizes of glass powder and different level of replacement.

In the experiment, the analysis was divided into two sections. One was microstructural analysis of cement paste incorporating with Glass Powder and another was mechanical strength behavior. Characterization of pozzolanicity in terms of hydration, development of hydrated products, identification of microstructure, chemical composition of hydrated products, structure of materials by means of hydration were analyzed through several experiments such as X-Ray Diffraction (XRD), Thermal Analysis (TGA and DTA), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) in microstructural analysis section. The main products during hydration that are Calcium Silicate Hydrate (C-S-H) and Calcium Hydroxide (CH) were investigated to know the pozzolanic characteristics of samples. Mechanical properties in terms of compressive strength test was investigated in another section. For both microstructural analysis and mechanical strength analysis, soda lime glass powder with varying particle sizes in the range of 150-75µm, 75-38µm and <38µm were used as cement replacement with progressive curing of 1, 7, 21, 28, 56, 90 Days. Cement was replaced with 10%, 20%, 30% and 40% glass powder with constant water to cement ratio 0.45.

In the FT-IR analysis, it was observed that cement paste with <38µm glass powder showed the strong peak of Calcium Silicate Hydrate (C-S-H) formation at higher stages for the replacement level of 10%, 20% and 30% with decreasing peak of another hydrated product Calcium Hydroxide (Ca(OH)2) which fulfills the characteristics of pozzolanicity in terms of hydration. A similar result was also found for X-Ray diffraction analysis. With the hydration of both C3S and C2S, the production of C-S-H increases with time. From thermal analysis, it can be concluded that the decomposition of CH is decreased with increasing the decomposition of C-S-H simultaneously at 90 days for 75-38µm and <38µm glass powder. The microstructure analysis, SEM shows the formation of C-S-H (vide infra) is surrounded by many needle-like structures. It proves the development of C-S-H which makes the structure dense and compacted in nature gradually, while a part of cement is replaced by glass powder. Low Ca/Si ratio of cement paste supports the findings of microstructural analysis. From compressive strength, it can be concluded that the optimum percentage for clear glass powder as cement replacement is 10% by weight in mortar production with water to cement ratio 0.45. The compressive strength decreases with increasing replacement level and lower particle size shows the highest strength.

Based on the results and observations, glass powder shows impressive results in the microstructure as well as compressive strength for <38µm glass powder. It can be concluded that the addition of waste glass can show better pozzolanic characteristics and enhance the performance of mechanical strength as cement replacement.

iv

ABSTRAK

Sejak beberapa tahun kebelakangan ini, penggunaan serbuk kaca buangan sebagai pengganti sebahagian simen telah diperkenalkan secara meluas untuk mengurangkan jumlah sisa kaca dari alam sekitar. Penggunaan kaca buangan sebagai gantian simen boleh menyumbang kepada pengurangan pengeluaran simen yang menyebabkan kesan rumah hijau supaya ia dapat mengurangkan tekanan persekitaran yang semakin meningkat. Tujuan karya ini ialah untuk melihat ciri-ciri pozzolanik daripada pes simen keras yang dimasukkan dengan serbuk kaca dan sifat-sifat kekuatan mekanikal apabila sebahagian mortar simen digantikan dengan pelbagai saiz serbuk kaca dan tahap penggantian yang berbeza.

Dalam eksperimen ini, analisis dibahagikan kepada dua seksyen. Pertama adalah analisis mikrostruktur pes simen digabungkan dengan serbuk kaca dan kedua adalah sifat kekuatan mekanikal. Pencirian pozzolanik dari segi penghidratan, pembangunan produk terhidrat, mengenalpasti mikrostruktur, komposisi kimia produk terhidrat, struktur bahan melalui penghidratan dianalisis melalui beberapa eksperimen seperti X-Ray Difrraction (XRD), kaedah terma (TGA dan DTA), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) dan Energy Dispersive Spectroscopy (EDS) dalam seksyen analisis mikrostruktur. Produk utama semasa penghidratan ialah Calcium Silicate Hydrate (C-S-H) dan Calcium Hydroxide (CH) yang telah diuji untuk mengetahui ciri-ciri pozzolanik sampel tersebut. Sifat mekanik dari segi ujian kekuatan mampatan telah diuji di seksyen yang lain. Bagi kedua-dua analisis mikrostruktur dan analisis kekuatan mekanikal, serbuk kaca soda kapur dengan pelbagai saiz zarah dalam lingkungan 150-75μm, 75-38μm dan <38μm telah digunakan sebagai pengganti simen dengan pengawetan progresif 1, 7, 21, 28, 56, 90 hari. Simen digantikan dengan 10%, 20%, 30% dan 40% serbuk kaca dengan nisbah air 0.45 yang berterusan.

Dalam analisis FT-IR, pemerhatian mendapati bahawa pes simen dengan serbuk kaca <38μm menunjukkan kemuncak kekuatan bagi pembentukan Calcium Silicate Hydrate (C-S-H) di peringkat yang lebih tinggi untuk tahap penggantian 10%, 20% dan 30% dengan penurunan kemuncak produk terhidrat lain iaitu Calcium Hydroxide (Ca(OH)2) yang memenuhi ciri-ciri pozzolanik dari segi penghidratan. Keputusan yang sama juga dijumpai untuk analisis X-Ray Diffraction. Dengan penghidratan kedua-dua C3S dan C2S, penghasilan C-S-H akan meningkat seiring dengan masa. Dari analisis terma, dapat disimpulkan bahawa penguraian CH adalah menurun dengan peningkatan penguraian C-S-H serentak pada 90 hari untuk 75-38μm dan <38μm serbuk kaca. Analisis mikrostruktur, SEM menunjukkan pembentukan C-S-H (vide infra) dikelilingi oleh struktur seperti jarum yang banyak. Ini membuktikan pembentukkan C-S-H yang menjadikan struktur padat dan dipadatkan dalam alam semula jadi secara beransur-ansur, manakala sebahagian daripada simen digantikan dengan serbuk kaca. Nisbah Ca/Si pes simen yang rendah menyokong dapatan analisis mikrostruktur. Dari kekuatan mampatan, dapat disimpulkan bahawa peratusan optimum untuk serbuk kaca yang jelas sebagai pengganti simen adalah 10% mengikut berat dalam pengeluaran mortar dengan 0.45 nisbah air untuk simen. Kekuatan mampatan menurun dengan tahap penggantian meningkat dan saiz zarah yang lebih rendah menunjukkan kekuatan tertinggi. Berdasarkan keputusan dan pemerhatian, serbuk kaca menunjukkan keputusan yang memberangsangkan dalam mikrostruktur serta kekuatan mampatan bagi serbuk kaca <38μm. Kesimpulannya, penambahan sisa kaca boleh menunjukkan ciri-ciri pozzolanik yang lebih baik dan meningkatkan prestasi kekuatan mekanikal sebagai penggantian simen.

v

TABLE OF CONTENTS

DECLARATION………………………………………………...…………………….....………..i

ACKNOWLEDGEMENT…………………………………………………………………...…....ii

ABSTRACT……………………………………………………………………………………...iii

ABSTRAK..……………………………………………………………………………………....iv

TABLE OF CONTENTS……………………………………………………………...…….…….v

LIST OF FIGURES………………………………………………………………………….….viii

LIST OF TABLES…………………………………………………….………...…………..….xiii

CHAPTER ONE……………………………..……………………………………………………1

INTRODUCTION………………………………………………………………..…………….1

1.1 INTRODUCTION……………………………………………………………...…………1

1.2 RESEARCH SIGNIFICANCE……………………………………....……………………3

1.3 RESEARCH HYPOTHESIS ……………………………………………...…………...…4

1.4 RESEARCH OBJECTIVES ………………………………………...……………………4

1.5 LAYOUT OF THESIS ………………………………………………………...…………5

CHAPTER TWO…………………………………………………………….……………………7

LITERATURE REVIEW………………………………………………………………………7

2.1 GENERAL…………………………………………...……………………………………7

2.2 DEFINITION AND CLASSIFICATIONS OF WASTE …………………………………7

2.3 WASTE GLASS…………………………………………………………..………………9

2.4 RECYCLING RATE OF GLASS……………………………………………………….11

2.5 USE OF WASTE GLASS AS CONSTRUCTION MATERIALS ……………………..14

2.5.1 Aggregate Replacement…………………………………………………………..…14

2.5.2 Cement Replacement………………………………………………………………..18

2.6 HYDRATION OF CEMENT …………………………………………………………...21

vi

2.7 POZZOLANIC MATERIAL …………………………………………………………....24

2.7.1 Pozzolanic Characterization of Glass Powder ……………………………………...25

2.8 SUMMARY……………………………………………………………………………...29

CHAPTER THREE…………………………………………………...…………………………30

MATERIALS AND METHODOLOGY……………………...………………………………30

3.1 INTRODUCTION………………………………………….……………………………30

3.2 MATERIALS………………………………………………………….…………………30

3.2.1 Cement………………………………………………...………….…………………32

3.2.2 Glass Powder………………………………………….…………………………….32

3.2.3 Fine Aggregate…………………………………………………...…………….……33

3.2.4 Water………………………………………….……………………………………..33

3.2.5 Ethanol Solution……………………………………………………………………..34

3.3 PREPARATION OF SAMPLE …………………………………………………………34

3.3.1 Cement Paste Sample Preparation……...…………………………………………...34

3.3.2 Cement Mortar Sample Preparation…….………………...…………………………35

3.4 TESTS CONDUCTED ………………………………………….……………………....37

3.4.1 Tests on Microstructure Analysis………………………………………….……..…37

3.4.1.1 Particle size distribution of glass powder……………………………….…….38

3.4.1.2 Fourier transform infrared spectroscopy………………………………………39

3.4.1.3 X-Ray diffraction ……………………………………………………………..41

3.4.1.4 Thermal analysis…………………………………………………………...….42

3.4.1.5 Microstructure analysis through SEM and EDS……………………………....45

3.4.2 Mechanical Strength Analysis: Compressive Strength Test………………………..….46

3.5 SUMMARY...…………………………………………………………………………....49

CHAPTER FOUR……………………..…………………………………………………………51

RESULTS AND DISCUSSION………………………………………………………………51

4.1 INTRODUCTION ………………………………………………………………………51

4.2 MICROSTRUCTURAL ANALYSIS ………………..…………………………………51

vii

4.2.1 Morphology and Particle Size Distribution of Glass Powder………………………….51

4.2.2 Fourier Transform Infrared Spectroscopy (FT-IR)…………………….………………53

4.2.2.1 FT-IR spectra of control cement paste………………………………………...54

4.2.2.2 FT-IR spectra of cement paste with Glass Powder A (150-75 µm)…………...55

4.2.2.3 FT-IR spectra of cement paste with Glass Powder B (75-38 µm)…………….59

4.2.2.4 FT-IR spectra of cement paste with Glass Powder C (<38 µm)………………62

4.2.3 X-Ray Diffraction (XRD)………………………………………………………..….65

4.2.3.1 XRD analysis of cement paste (control)……………………...……………….66

4.2.3.1 XRD analysis of cement paste containing Glass Powder………………….….67

4.2.4 Thermal Analysis……………………………………………………...…………….74

4.2.4.1 Thermogravimetric analysis (TGA)…………………………………………...74

4.2.4.2 Differential thermal analysis (DTA)…………………………………………..80

4.2.5 Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy

(EDS)…………………………………………………………………………….… 84

4.3 MECHANICAL STRENGTH PROPERTIES ……………………….…………………91

4.3.1 Compressive Strength Incorporating Glass Powder A…...…………………………....91

4.3.2 Compressive Strength Incorporating Glass Powder B…………………………..……..92

4.3.3 Compressive Strength Incorporating Glass Powder C……………………………........93

4.3.4 Comparison with Glass Sizes…...………………………………………………...……93

4.3.5 Comparison with Water to Cement Ratio…….…………………………………..……94

4.4 SUMMARY…………………………………………………………………………...…96

CHAPTER FIVE………………………………………………...………………………………98

CONCLUSIONS AND RECOMMENDATIONS……………………………………………98

5.1 CONCLUSIONS……………………………………………………………...…………98

5.1.1 Microstructural Analysis……………………………………………………….……98

5.1.2 Mechanical Strength Behavior………………………………………………………99

5.2 RECOMMENDATIONS FOR FUTURE WORK.………………………………….…..100

REFERENCES…………………………………………………………………………………101

APPENDIX……………………………………………………………………………………..112

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LIST OF FIGURES

Figure 2.1 Glass Practice at North American market in 2009 (Tray Granger 2009)………….11

Figure 2.2 Two years recycling rate by country (www.container-recycling

.org/index.php/glass-containers)………………………………………….…….….13

Figure 2.3 Morphology of control mortar and glass powder containing control mortar…..….17

Figure 2.4 Compressive strength test result at different ages ( Nassar and Soroushian, 2011).20

Figure 2.5 Reaction rates of minerals over time during cement hydration process of portland

cement (Mitchell, et.al. 1996)……………………………………………………...23

Figure 2.6 DTG curves of the glass-cement pastes for 10% substitution at 360 days

(Karamberi and Moutsatsou ,2005)………………… ………….………………....25

Figure 2.7 Particle size and shape of ground waste glass of 45 - 75μm (left) and 0 - 45μm

(right) particle range, after grinding. (Pereira et al., 2005)………….…...………...26

Figure 2.8 Scanning electron microscope image of a fractured surface of control concrete

(Nassar and Soroushian, 2011)………………………………...…………...……...27

Figure 2.9 Scanning electron microscope image of a fractured surface of 20% glass concrete

(Nassar and Soroushian, 2011)………………………………...……………....…..27

Figure 2.10 EDS plot of (a) concrete containing glass, (b) control concrete

(Nassar and Soroushian,2012)……………………………………...………….......28

Figure 2.11 X-ray spectrum of control, FRFG and FRCGN specimens (a) CH peaks and (b) C-

S-H peaks (Aly et al., 2011)…………........…...…………………………………...28

Figure 3.1 Portland cement manufacturing……………………………….…………………...31

Figure 3.2 Cement paste samples into 30ml plastic tubes…...………………..…………...….34

Figure 3.3 Cement mortar samples with plastic cubes………...……………….……………..36

Figure 3.4 Particle size analyzer……………...…………………………....……………….…38

Figure 3.5 IR spectra of hydrated Portland cement at 28 days (Trezza, 2007)…….……….…40

Figure 3.6 Fourier Transform Infrared Spectrometer IRAffinity-S1……………………..…...41

Figure 3.7 XRD Spectra of cement paste at 28 days…………………………………….……42

ix

Figure 3.8 Calculation of TGA mass loss (Anandhan, 1979)…...……………......…………...43

Figure 3.9 Thermal Analysis Equipment……………………………………..……………….44

Figure 3.10 Morphology of C-S-H, CH and Ettringite………………...…..….………………..45

Figure 3.11 Samples for SEM and EDS……………………………...…..………………...…..46

Figure 3.12 ELE-International ADR1500 Compression Machine………………………..…....47

Figure 4.1 Morphology of glass powder (a) Glass Powder A, (b) Glass Powder B and (c) Glass

Powder C…………..……………………………………...………………………..52

Figure 4.2 Cumulative Particle Size Distribution curve………………………….……...........53

Figure 4.3 FT-IR spectra of control sample centre around (i) 953 cm-1 and (ii) 3640 cm-1 at (a)

Day 1 (b) Day 7 (c) Day 28 (d) Day 56 and (e) Day 90…...…………………........55

Figure 4.4 FT-IR spectra of cement paste with 10% glass powder A at (i) 953 cm-1 and (ii)

3640 cm-1 (a) Day 1 (b) Day 7 (c) Day 28 (d) Day 56 and (e) Day 90……….........56


3640 cm-1 (a) Day 1 (b) Day 7 (c) Day 28 (d) Day 56 and (e) Day 90……...……..57




3640 cm-1 (a) Day 1 (b) Day 7 (c) Day 28 (d) Day 56 & (e) Day 90………...........59

Figure 4.8 FT-IR spectra of cement paste with 10% glass powder B at (i) 953 cm-1 and (ii)







3640 cm-1 (a) Day 1 (b) Day 7 (c) Day 28 (d) Day 56 and (e) Day 90……..….......62

x

Figure 4.12 FT-IR spectra of cement paste with 10% glass powder C at (i) 953 cm-1 and (ii)

3640 cm-1 (a) Day 1 (b) Day 7 (c) Day 28 (d) Day 56 and (e) Day 90………..…...63


3640 cm-1 (a) Day 1 (b) Day 7 (c) Day 28 (d) Day 56 and (e) Day 90………….....63


3640 cm-1 (a) Day 1 (b) Day 7 (c) Day 28 (d) Day 56 and (e) Day 90……...…......64



Figure 4.16 X-Rays diffraction pattern of cement paste (control) specimen…………………...66

Figure 4.17 X-rays pattern of cement paste incorporating 10% Glass Powder A…………..….67


Figure 4.19 X-rays pattern of cement paste incorporating 30% Glass Powder A……………...68


Figure 4.21 X-rays pattern of cement paste incorporating 10% Glass Powder B…………..….70

Figure 4.22 X-rays pattern of cement paste incorporating 20% Glass Powder B……………...70



Figure 4.25 X-rays pattern of cement paste incorporating 10% Glass Powder C……….....…..72

Figure 4.26 X-rays pattern of cement paste incorporating 20% Glass Powder C………..…….73

Figure 4.27 X-rays pattern of cement paste incorporating 30% Glass Powder C………..…….73

Figure 4.28 X-rays pattern of cement paste incorporating 40% Glass Powder C……………...74

Figure 4.29 TGA curves for control cement paste at a) 28 days and b) 90 days……….……....76

Figure 4.30 DTA curve of Glass Powder A at 28 Days……………………….………………..81

Figure 4.31 DTA curve of Glass Powder B at 28 Days…………………...…………..………..81

xi

Figure 4.32 DTA curve of Glass Powder C at 28 Days…………………………...……..……..82

Figure 4.33 DTA curve of Glass Powder A at 90 Days………………………………..….……83

Figure 4.34 DTA curve of Glass Powder B at 90 Days…………………………...…..…...…...83

Figure 4.35 DTA curve of Glass Powder C at 90 Days…………………………...…………....84

Figure 4.36 Control sample at 28 days………………………………………………….……...85

Figure 4.37 Cement paste containing Glass Powder A (a) 10%, (b) 20%, (c) 30% and (d) 40%

at Day 28…...……...……………………………………………..…...………........86

Figure 4.38 Cement paste containing Glass Powder B (a) 10%, (b) 20%, (c) 30% and (d) 40%

at Day 28…….……..…………………………………………………..………......87

Figure 4.39 Cement paste containing Glass Powder C (a) 10%, (b) 20%, (c) 30% and (d) 40%

at Day 28…………………………………...……………………..…………..........88

Figure 4.40 EDS analysis of control sample at 28 days…………………………...…….....…..89

Figure 4.41 Compressive Strength Results of Mortar with Glass Powder A…………..……....91

Figure 4.42 Compressive Strength Results of Mortar with Glass Powder B…………………...92

Figure 4.43 Compressive Strength Results of Mortar with Glass Powder C………………..….93

Figure 4.44 Comparison on water to cement ratio at Glass Powder A……...………..………...94

Figure 4.45 Comparison on water to cement ratio at Glass Powder B...…………………..…...95

Figure 4.46 Comparison on water to cement ratio at Glass Powder C…………………….…...96

Figure A.1 TGA curves for cement paste with 10% Glass Powder A at a) 28 days and b) 90

days..………………………………………………………………….….……….113

Figure A.2 TGA curves for cement paste with 10% Glass Powder B at a) 28 days and b) 90

days………...………………………………………………………………...…...113

Figure A.3 TGA curves for cement paste with 10% Glass Powder C at a) 28 days and b) 90

xii

days……..……………………………………………………………….....……..114

Figure B.1 TGA curves for cement paste with 20% Glass Powder A at a) 28 days and b) 90

days…………………………………………………………………..…………...114

Figure B.2 TGA curves for cement paste with 20% Glass Powder B at a) 28 days and b) 90

days..……………………………………………………………………..……….115

Figure B.3 TGA curves for cement paste with 20% Glass Powder C at a) 28 days and b) 90

days…...………………………………………………………………..…………115

xiii

LIST OF TABLES

Table 2.1 Degeneration rate of solid waste (NSWAI, 2012)……………………………………8

Table 2.2 Chemical composition of selected commercial glasses (Mclellan and Shand, 1984)10

Table 2.3 Glass generation, disposing and recovery rate (Environmental Protection, 1990).....12

Table 3.1 Physical properties of ordinary Portland cement……….…………………………...31

Table 3.2 Chemical composition of ordinary Portland cement………………….………..…...32

Table 3.3 Mixing proportion of cement paste samples with w/c 0.45………………………....35

Table 3.4 Mixing proportion of cement mortar samples with w/c 0.45…………..…..……….37

Table 3.5 Mixing proportion of cement mortar samples with w/c 0.40………………...….….37

Table 3.6 Assignments of IR fundamental frequencies of the hydrated Portland cement

(Trezza, 2007)…………………………………….…….……...……………………40

Table 3.7 Test program for each test conducted …………….………………………….……..48

Table 4.1 Percent Weight loss of paste contains Glass powder according to the temperature and

time ranges…….…………………………………………………………………….76

Table 4.2 Ca/Si ratio of samples using EDS analysis………………….………………………90

1

CHAPTER ONE

INTRODUCTION

1.1 INTRODUCTION

The generation of waste materials has enormously increased according to the rapid growth

of industry and population explosion. Most of the waste materials are solid wastes consisting

industrial waste, clinical waste and domestic waste among all generated waste materials. Such

waste materials had been dumped into the low-lying areas as landfill materials in earlier days.

Dumping waste materials at low laying areas has become a critical issue due to the scarcity of

land area. In addition, greater portion of these wastes originated present time do not decompose

by it-self, that is essential biological, chemical and physical changes do not occur and will

remain in the environment for hundreds and perhaps thousands of years. Waste glass is such

solid waste materials that not only accumulate on the landfill also contribute to the

environmental problems in the present time.

Glass is one of the most indispensable materials used in a wide variety of applications into

man's life. The amount of waste glass increases in the environment with the increment of usages

of glass in every day’s life. Theoretically, glass is a 100% recyclable material; it can be

indefinitely recycled without any loss of quality (Sobolev et al., 2006). Nevertheless, the

recycling rate of waste glass is quite low compared to the other solid wastes in many countries

due to inconsistent properties, expensive cleaning and color sorting cost, prohibitive shipping

cost and growing cost of land filling. For these reasons, almost 90% of glasses are not being

recycled in Malaysia (Krishnamoorthy and Zujip, 2013). Environmental regulations and

deficiency of landfill space also encourage the use of waste glass in concrete production.

Cement is one of the oldest binding materials widely used in construction industry around

the world which is considered as one of the primary producer of carbon dioxide, contributing

about 7-8 percent to the overall carbon dioxide production in the world. As in the production of

one ton of Portland cement about one ton of carbon dioxide is released into the environment and

2

contributes to the greenhouse gas which is the main issue in the global warming and the

development of holes in the ozone layer (Sprince et al., 2011). Global Carbon dioxide emissions

by fossil fuels and producing cement reached 9.7 billion tons in 2012, as well as the emission for

2013 expected to 9.9 billion tons (Levin, 2013). Increment of CO2 emission from burning fossil

fuels and producing cement exceeded 58 percent compared to 1990s bench level. Atmospheric

levels of carbon dioxide have risen by about 30 percent over the past 200 years. If the CO2

production in cement factories could be decreased by 10%, the overall release would be

decreased by 5.2% into the atmosphere (Sprince et al., 2011). It is very high time to minimize the

cement production and utilize the waste glass so that it can cut down the increasing

environmental pressure. Using waste glass as cement replacement in concrete construction is

advantageous for this purpose.

The feasibility of waste glass as cement replacement depends on its microstructure

properties such as morphology, chemical composition, major phase present in cement paste and

pozzolanic characteristics by means of hydration. Waste glass can be used to replace cement, but

it must show either binding properties or pozzolanic properties. A typical pozzolanic material

features three characteristics: it should contain high silica, be X-ray amorphous, and have a large

surface area. Glass has sufficient silica content and is amorphous in nature. The glass might

satisfy the basic requirements for a pozzolan if it could be ground to as size fine enough to pass

the alkali silica reaction and to activate the pozzolanic behavior. It was examined that if the glass

was powder to a particle size of 300 µm or smaller, it can act as a pozzolanic material to react

with portlandite in hydrated cement to form Calcium Silicate Hydrate (C-S-H) in increasing

strength and durability of concrete because of the high silica content in glass powder (Shao et al.,

2000; Shayan and Xu, 2004, 2006; Shi et al., 2005; Ozkan and Yuksel, 2008; Taha and Nounu,

2008). The pozzolanic properties of glass powder can be obtained from its microstructure

analysis in terms of hydration. Investigation of pozzolanicity of different sizes of waste glass as

cement would be a significant approach in the development of new construction material.

Moreover, as the size of the glass powder decreases, the strength in terms of mechanical

properties increases reported by Dhirendra et al., (2012), Patil and Sangle, (2013) and Carsanaa

et al., (2014). In this current study, glass powder with varying particle sizes in the range of 150-

75µm, 75-38µm and <38µm were used as cement replacement with constant water to cement

3

ratio 0.45 to get better understanding to the size effect in both microstructural analysis and

mechanical strength analysis.

Recycling of each ton of glass saves over one ton of natural resources, and recycling of

every six tons of container glass results in the reduction of one ton of carbon dioxide emission

(Nassar and Soroushian, 2011). The production cost of concrete would decrease, and our

industry would become more environmentally friendly. These not only help in the reuse of waste

glasses but also create a cleaner and greener environment.

1.2 RESEARCH SIGNIFICANCE

As a binding material, cement performs a significant role in civil engineering constructions

around the world. However, the production of cement releases carbon dioxide (CO2) in the

atmosphere both directly and indirectly which contributes to the global warming. CO2 is emitted

directly as a byproduct of clinker during the heating of limestone (CaCO3). The burning fossil

fuels to heat the kiln result CO2 emission indirectly. Using waste glass as partial replacement of

cement in construction would be the plausible approach to shape the friendly environment. For

this purpose, the waste glass must have the properties of composition, fineness and

pozzolanicity. Glass in theory is pozzolanic in nature owing to amorphous and containing high

quantities of silicon and calcium and when it is finely ground indeed. When the particle size is

below 100 micron glass may become pozzolanic. The eventual focus of this research is to the

characterization of cement with glass powder which is very imperious to know the

microstructural behavior. It is enable to differentiate the effect of hydration when the particle

size of waste glass in the range of 150-75 µm, 75-38 µm and <38 µm. The formation of

hydration compounds Calcium Silicate Hydrate (C-S-H) and Calcium Hydroxide (CH) indicate

the strength and durability of the mortar. The performance of hydration depends mostly on water

to cement ratio (w/c). The amount of unreacted cement constituents and composition can be

recognized mostly in the microstructure analysis in terms of hydration by the formation of

hydration products C-S-H and CH. Major hydrated products present in the cement paste (as

identified by X-RD) and their relative proportion (as measured by EDS) can be found through

microstructure. Morphology of structure (as displayed by SEM) and mass loss (as calculated by

TGA analysis) also helps to support their findings. The strength of mortar or concrete largely

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depends on the cement replacement level. In this study, cement is partially replaced with glass

powder by replacement level of 10%, 20%, 30% and 40% with constant water to cement ratio

0.45 to find the optimum content of glass powder as replacement of cement. The comprehensive

outcomes obtained from this work will save a significant amount of energy and reduce the

amount of air pollutants and extends the life of our landfill.

1.3 RESEARCH HYPOTHESIS

Utilization of waste glass as construction material has widely introduced in recent years to

reduce the use of natural material in construction and waste disposal costs. Many alternative uses

for recycled glass based products have been used without compromising on either cost or quality.

What is not well understood is whether the use of waste glass as partial replacement of cement

can exhibit the pozzolanic properties during hydration process. The use of waste glass as cement

replacement will not be endurable for construction purpose until we understand the

microstructural behavior of cement paste incorporating with glass powder as structure of

hydrated products, chemical constituents, major phase present in cement paste and pozzolanic

characteristics due to hydration. It appears that the use of waste glass as cement replacement will

improve the cement matrix through the formation of more Calcium Silicate Hydrate (C-S-H) by

consuming Calcium Hydroxide (Ca(OH)2) during hydration and will create the cement system

quite dense, homogeneous and compacted in nature. The use of cement replaced by glass powder

will prolong our landfill sites, save significant amount of energy and reduce the amount of CO2

emission that contributes greenhouse gas into the environment.

1.4 RESEARCH OBJECTIVES

The aims of this study is to investigate the characteristics of pozzolanic properties of glass

powder as replacement of cement and its effect on strength in terms of mechanical properties.

This study is focused on experimental investigation to achieve the following objectives:

1. To identify the pozzolanic characteristics of hardened cement paste incorporating glass

powder by the formation of Calcium Silicate Hydrate (C-S-H) and Calcium Hydroxide

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(Ca(OH)2) through absorption intensity of infrared spectroscopy and also weight loss due

to the decomposition of C-S-H and Ca(OH)2 using thermal analysis.

2. To analyze the major phase present in the cement paste in terms of hydration when

cement is replaced by different size and different amount of glass powder.

3. To obtain the morphology and chemical compositions of cement paste by means of

scanning electron microscopy (SEM) together with energy dispersive spectroscopy

(EDS).

4. To analyze the strength characteristics of mortar containing glass powder and to support

the microstructure analysis results.

1.5 LAYOUT OF THE THESIS

To obtain the overview of this study at a glance, the content of the thesis with a short

description is stated as follows:

Chapter 1: A background of necessities of waste glass in concrete production, objectives of this

current research, significance of research and organization of the thesis have been described in

this chapter.

Chapter 2: Literature review gives an overview on background of materials used with the recycle

rate, the utilization of waste glass as aggregate, use of waste glass as cement replacement,

pozzolanic characteristics of waste glass, brief of cement hydration are described here.

Chapter 3: The experimental program, materials, mix proportion, sample preparation, test

instrument are described on chapter three.

Chapter 4: The results obtained from microstructural analysis and mechanical strength analyses

are discussed in this chapter. It also includes comparison between water to cement ratio with

compressive strength results.

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Chapter 5: This chapter summarizes the work conclusions based on the outcomes gathered.

Recommendation is included in this chapter for future works.

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CHAPTER TWO

LITERATURE REVIEW

2.1 GENERAL

The purpose of this chapter is to review previous works related to waste glass, sources of

waste glass, recycling rate of waste glass, history of glass recycling, uses as construction

materials such as aggregate replacement and cement replacement, pozzolanic characteristics,

hydration of cement, and microstructure analysis of glass powder in terms of pozzolanic

characterization.

2.2 DEFINITIONAND CLASSIFICATIONS OF WASTE

The generation of waste is a continuous practice in every single way from daily activities.

The useless and unwanted products in the solid state derived from the activities of and discarded

by society can be defined as solid waste. Solid wastes are one of the three weightier problems in

Malaysia. Currently, over 23000 tons of solid waste are generated every day in Malaysia; this

amount is expected to rise to 30000 tons by the year 2020. Due to the development and the

growth of population, the generation of solid waste has been increasing continuously and only

less than 5% of solid waste is being recycled (GEC, 2012). The following types of waste which

are usually produced, are given below

1. Municipal Solid Waste

2. Industrial Waste as Hazardous Waste

3. Biomedical Waste

Municipal Solid Waste (MSW) can be defined using Chapter 21.3 of Agenda 21 (United

Nations Conference on Environment and Development, Rio de Janeiro, June 14, 1992 Chapter

21 “Environmentally sound Management of Solid Wastes and Sewage –related issues”

“Solid waste…include all domestic refuse and non-hazardous wastes such as commercial

and institutional wastes, street sweepings and construction debris. In some countries the solid

8

wastes management system also handles human wastes such as night-soil, ashes from

incinerators, septic tank sludge and sludge from sewage treatment plants. If these wastes

manifest hazardous characteristics, they should be treated as hazardous wastes.”

MSW, more commonly known as trash or garbage (US), refuse or rubbish (UK) is a waste

type consisting of everyday items that are discarded by the public, whereas hazardous and

industrial waste poses substantial or potential which is highly toxic to human, animals and plants

are highly explosive and corrosive. The waste generated from biological and medical sources and

activities, for example, the diagnosis, prevention, or treatment of diseases or immunization of

people or animals or in research activities is known as biomedical waste.

MSW consists of domestic waste, commercial and community waste, construction and

demolition debris and the institutional garbage including furniture, packaging products, glass,

food scraps, batteries, newspapers, clothing and bottles. This waste is produced mainly from

residential and commercial areas.

Table 2.1 Degeneration rate of solid waste (NSWAI, 2012)

The type of litter we generate and the approximate time it takes to degenerate

Type of litter Approximate time it takes to degenerate the litter

Organic waste such as vegetable and fruit peels, leftover foodstuff, etc.

a week or two.

Paper 10–30 days

Cotton cloth 2–5 months

Wood 10–15 years

Woolen items 1 year

Tin, aluminium, and other metal items such as cans 100–500 years

Plastic bags one million years?

Glass bottles Undetermined

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Among all solid wastes, the generation of waste glass has increased rapidly with rising

population and switching to new food habits and lifestyle. Nevertheless the degeneration rate of

waste glass is quite low compared to the other MSW as shown in Table 2.1.

2.3 WASTE GLASS

Glass is one of the oldest man-made versatile substances served as a universal packaging

container, flat glass and glass bottles. Now-a-days, glass is used to hold everything from soda to

perfume. Glasses can be classified into the miscellaneous categories, based on their chemical

compositions: alkali silicates, soda-lime glasses, borosilicate glasses, lead glasses, barium

glasses, and aluminosilicate glasses. Soda-lime glasses would be made up with nearly 73% SiO2,

13–13% Na2O and 10% CaO which is the most dominant type of glass used for glass containers

(bottles and jars) for beverages, food and other commodity items (Shi and Zheng, 2007).

According to their chemical composition, soda-lime glasses will be pozzolanic-cementitious

materials. Lead glasses will be the second major type, from the color TV funnel, neon tubing,

electronic parts, etc. Small amounts of additives are often added during the production of glasses

to give glasses different colors or to improve specific properties (Shi and Zheng, 2007).

Chemical compositions of selected commercial glasses (McLellan and Shand, 1984) are shown

in Table 2.2. In waste glasses, soda lime glasses are over 80% by weight of total glass wastes as

containers, floats and sheets. On a color basis, 63% are clear, 25% are amber, 10% are green and

2% are blue or other colors (Shi and Zheng, 2007).

Glass becomes a vital element of various products that we use our day to day life, most often

without noticing it. Glass is mostly used in packaging (jars for food, bottle for beverages, flacon

for cosmetics and pharmaceuticals, health and science application), tableware (Drinking glass,

plates, cups, bowls), housing and buildings (Windows, facades, conservatory insulation,

reinforcement structures), interior design and furniture (mirrors, partitions, balustrades, tables,

Shelves, lighting), appliances and electronics (oven doors, cook top, TV, computer screens,

smart phones), automotive and transport (Wind screens, back lights, light weight but reinforced

structural components of cars, aircrafts, ships etc). Modern science has been blessed with the

glass as medical technology, bio-technology, life science engineering, radiation protection from

X-Rays (radiology) and gamma-ray (nuclear), fibre optic Cables (Phones, TV, computer: to carry

characterization of pozzolanic properties of waste … of pozzolanic properties...properties of...

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