Embed Size (px)
Citation preview
EFFECT OF BOTTOM ASH ON THE STRENGTH CHARACTERISTICS OF
FLY ASH AND BOTTOM ASH MIXTURES
JACKY LING JIA YII
A project report submitted in partial fulfillment of the
requirements for the award of the degree of
Master of Engineering (Civil)
Faculty of Civil Engineering
Universiti Teknologi Malaysia
JANUARY 2013
iv
To my beloved parent, siblings, and friends
Thanks for your never ending love and support
iv
ACKNOWLEDGEMENTS
First of all, I would like to express my sincere appreciation to my project
supervisor, Prof. Dr. Aminaton Marto for her generous advice, patience, guidance
and encouragement throughout the duration of my preparation and writing this
project report.
Secondly, I would like to express my gratitude to Mr. Abdul Rahim Awang, a
PhD candidate, for his guidance and sharing his useful information and experience
related to this projects. Besides, thanks to all technician at Universiti Teknologi
Malaysia (UTM) and Universiti Tun Hussein Onn Malaysia (UTHM), who
generously spend their precious time for helping me in the laboratory works.
Furthermore, I would also like to express my sincere thanks to my senior and
friends, who had given me a lot of guidance and advice for the completion of this
Master project.
Finally, I am most thankful to my parents and family for their continuous
support and encouragement given to me unconditionally in completing this Master
project. Without the contribution of all those mentioned above, this work would not
have been possible.
v
ABSTRACT
One of the sources to produce electricity is coal. The major problem of the
coal combustion based power plant is producing huge quantities of solid waste. Fly
ash (FA) and bottom ash (BA) are two major contributions in the coal combustion
products (CPP). Generally, most CPP are just dumped into the waste pond. The
insufficient place for waste dumping is becoming an issue since the amount of CPP
waste is increasing drastically. Recently, there are efforts to use the FA and BA
together as mixtures in geotechnical engineering works. This paper focuses on the
effect of BA content on the strength characteristic of fly ash and bottom ash mixtures,
for coal ash taken from the Tanjung Bin power plant in Johor, Malaysia. This study
investigates the effect of curing period on the morphology, chemical and strength
characteristic of FA-BA mixtures that consists of 30 % and 70% BA.The mixtures
had been tested in laboratory through Scanning Electron Microscopic test, X-Ray
Fluorescences test and Consolidated Undrained triaxial test. Major chemical
compostion of FA-BA mixtures are silica, alumina, ferum oxide and calcium oxide.
The value of modulus of elasticity decreased with the increase of bottom ash content
from 30% to 70% in the ash mixtures. The internal friction angle at critical state,c’,
was decreased as the content of BA is increased from 30% to 70%. Without curing
periods, the increased of BA content from 30% to 70% did not give any significant
effect on the critical state shear strength. However, after 28 days curing periods, the
c’ was increased, but it is not that significant. It is also observed that the c’ of both
mixtures with 30%BA and 70%BA are in the same range as the typical dense sands.
Generally, it can be concluded that there is no significant effect on the shear strength
properties at critical state for FA-BA mixtures at 30%BA and 70%BA. Hence, there
will be a great potential to use a large quantity of BA in the mixtures without
compromising the strength which can be a great benefit for usage in various
geotechnical engineering works.
vi
ABSTRAK
Arang batu merupakan salah satu sumber untuk menghasilkan elektrik.
Masalah utama bagi pembakaran arang baru di loji kuasa adalah pembakaran arang
batu telah menghasilkan sisa pepejal dalam kuantiti yang banyak. Abu terbang (FA)
dan abu dasar (BA) adalah dua sumbangan besar dalam produk pembakaran arang
batu (CPP). Secara umumnya, CPP hanya akan dibuang ke dalam kolam sisa. Tempat
pelupusan sisa buangan yang tidak mencukup telah menjadi satu isu. Ini berpunca
daripada jumlah sisa CPP telah menunjukkan peningkatan yang drastik.
Kebelakangan ini, terdapat usaha-usaha untuk menggunakan FA dan BA bersama-
sama sebagai campuran dalam kerja-kerja kejuruteraan geoteknik. Kajian ini
memberi tumpuan kepada campuran abu arang batu dari loji kuasa Tanjung Bin di
Johor, Malaysia. Kajian ini menyiasat kesan tempoh pengawetan pada ciri morfologi,
kimia dan kekuatan campuran abu terbang dan abu dasar (FA-BA) yang mana ia
terdiri daripada 30% dan 70% campuran BA. Campuran abu ini telah diuji dalam
makmal melalui ujian pengimbasan elektron mikroskopik, ujian x-ray fluorescences
dan ujian tiga paksi pengukuhan tak tersalir. Komposisi kimia yang utama dalam
campuran FA-BA adalah silika, alumina, ferum oksida dan kalsium oksida. Nilai
modulus keanjalan menurun dengan peningkatan kandungan abu dasar dari 30% ke
70% dalam campuran abu. Sudut geseran dalaman pada keadaan kritikal telah
menurun apabila kandungan BA meningkat dari 30% ke 70%. Tanpa pengawetan,
peningkatan kandungan BA daripada 30% kepada 70% tidak memberi apa-apa kesan
yang besar ke atas kekuatan ricih dalam keadaan kritikal. Walaubagaimanapun,
selepas 28 hari pengawetan, c’ telah meningkat, tetapi tidak ketara. Semua c’
ditemui dalam campuran FA-BA adalah hampir sama seperti c’ yang ditunjukkan
oleh pasir padat yang biasa. Secara umumnya, ia boleh membuat kesimpulan bahawa
campuran FA-BA pada 30% BA dan 70% BA tidak memberi kesan yang ketara ke
atas sifat-sifat kekuatan ricih pada keadaan kritikal. Maka, potensi untuk
menggunakan BA dalam kuantiti yang besar ke dalam campuran tanpa menjejaskan
kekuatan adalah besar. Ini boleh menjadi manfaat yang besar dalam pelbagai kerja
kejuruteraan geoteknikal.
vii
TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES x
LIST OF FIGURES xii
LIST OF SYMBOLS xviii
1 INTRODUCTION
1.1 Background 1
1.2 Statement of problems 2
1.3 Objectives 3
1.4 Scope and limitations of study 3
1.5 Significance of study 4
viii
CHAPTER TITLE PAGE
2 LITERATURE REVIEW
2.1 Introduction 5
2.2 Fly ash 7
2.2.1 Class F fly ash 10
2.2.2 Class C fly ash 11
2.2.3 Pozzolanic activity of fly ash 12
2.3 Utilization of fly ash 14
2.3.1 Fly ash in cement concrete 15
2.3.2 Fly ash in embankment and structural fills 16
2.4 Bottom ash 16
2.4.1 Utilization of bottom ash 18
2.5 Shear strength of fly and bottom ash mixture 19
2.6 Tangent constrained modulus 22
2.7 Unconfined compressive strength 28
2.8 Peak friction angle and critical state friction angle 29
2.9 Critical state theory 35
2.9.1 Critical state line (CSL) 35
2.9.2 State boundary surface 37
2.10 Critical state of FA-BA Mixture 42
3 METHODOLOGY
3.1 Introduction 47
3.2 Material collection 49
3.3 Sample preparation 51
3.4 Morphology of mixture 53
3.5 Chemical properties of mixture 54
3.6 Consolidation undrained (CU) triaxial compression 55
test.
ix
CHAPTER TITLE PAGE
3.6.1 Preparation of Consolidated Undrained (CU) 55
Triaxial Compression Test
3.6.1.1 Porous discs 56
3.6.1.2 Rubber membrane 57
3.6.1.3 O-ring 58
3.6.1.4 De-aired water 59
3.6.2 Installation and procedure of consolidated 60
undrained triaxial test
3.6 Data analysis 63
4 RESULTS AND DISCUSSIONS
4.1 Introduction 65
4.2 Morphology characteristics 66
4.3 Chemical composition 70
4.4 Consolidated Undrained Triaxial Test 73
4.4.1 Stress-strain and pore water pressure reponses 73
4.4.2 Modulus of elasticity 81
4.5 Critical state line 85
4.6 Shear Strength 90
5 CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 90
5.2 Recommendations 91
REFERENCES 92
x
LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Chemical composition of coal fly ash 12
2.2 Utilization of coal fly ash in the United States, 15
Europe and China
2.3 Chemical composition of coal bottom ash 18
2.4 The E value suggested 27
2.5 Shear strength values of mixtures at different fly ash 28
composition at various cuing periods.
2.6 Strength parameters from direct shear tests (Peak values) 37
2.7 Undrained strength parameters from triaxial tests 37
(Standard Proctor optimum)
2.8 Drained strength parameters from triaxial tests 38
2.9 Effective strength parameters from triaxial tests 38
(Standard Proctor optimum)
xi
TABLE NO. TITLE PAGE
3.1 Mixing proportion of 30% bottom ash and 70% bottom 51
ash mixtures for one sample
4.1 XRF analysis of 30% bottom ash 71
4.2 XRF analysis of 70% bottom ash 71
4.3 Comparison between 30% and 70% fly ash on deviator 80
stress and axial strain at peak
4.4 Comparison between 30% and 70% fly ash on deviator 80
stress and axial strain at critical state
4.5 Comparison in secant modulus of ,Es, for every samples 82
4.6 Comparison between 30% bottom ash and 70% bottom 83
ash on cohesion and angle of shear resistance
4.7 Comparison between 30% bottom ash and 70% bottom 88
ash on shear strength
4.8 Comparison between 30% fly ash and 70% Bottom ash 89
on percentage increase of shear strength before and after
28 curing days
xii
LIST OF FIGURES
FIGURE NO. TITLE PAGE
2.1 Typical thermal power plant and resulting waste 7
generated
2.2 Scanning electron microscopy (SEM) photographic 10
of fly ash
2.3 Scanning electron microscopy (SEM) photographic 17
of bottom ash
2.4 Stress-strain and volume change results from 20
consolidated-drained triaxial tests completed on ash
mixtures from (a) and (b) Wabash River plant; and
(c) and (d) A. B. Brown plant
2.5 Volume change behaviour from CID triaxial test 21
performed at different confining stresses on ash mixtures
from (a) Wabash River plant; and (b) A. B. Brownplant
2.6 Graph of deviator stress versus axial strain 22
xiii
FIGURE NO. TITLE PAGE
2.7 Definition of soil modulus 24
2.8 Tangent constrained modulus of ash mixtures and sands 25
2.9 Peak friction angle versus compaction level, confining 31
stress, and fly ash content: (a) Wabash River plant; and
(b) A. B. Brown plant
2.10 Critical state friction angle of ash mixtures 32
2.11 Critical state line and stress paths for undrained 37
loading on a normally consolidated clay
2.12 q’/v/p’ triaxial test result 38
2.13 Three dimension projection of critical state line 39
2.14 The critical state boundary surface 40
2.15 Consolidated undrained compression test results 42
for normally consolidated sample
2.16 Failure points for consolidated undrained compression 43
test on isotropically consolidated specimens of all stress
histories in q-p’ space
xiv
FIGURE NO. TITLE PAGE
2.17 Failure points for consolidated undrained compression 43
test on isotropically consoliated specimens of different
stress histories in υ – p’ space
2.18 Critical state line in υ – In p’ space 45
2.19 Effective stress paths from consolidated undrained 45
compression test of normally consolidated samples
in q-p’ space
2.20 Critical state boundary surfaces from consolidated 46
undrained compression test in q/p’e and q/p’e space.
3.1 Flow chart of the activities in the study 48
3.2 Tanjung Bin Power Plant 49
3.3 Bottom ash disposal area 50
3.4 Silo for fly ash storage 50
3.5 Sample of 30% bottom ash 52
3.6 Sample of 70% bottom ash 52
3.7 ZEISS SUPRA 35-VP 53
xv
FIGURE NO. TITLE PAGE
3.8 Bruker AXS Model S4 Pionner 54
3.9 Porous discs 56
3.10 Rubber Membrane 57
3.11 O-ring 58
3.12 De-aired water apparatus 59
3.13 Triaxial machine 61
3.14 Sample in the triaxial machine 61
4.1 SEM micrograph of coal ash mixtures particles from 68
Tanjung Bin power plant at 0 curing days
(Magnification x1000)
4.2 SEM micrograph of coal ash mixtures particles from 70
Tanjung Bin power plant at 28 curing days
(Magnification x1000)
xvi
FIGURE NO. TITLE PAGE
4.3 Consolidated undrained compression test results for 74
normally consolidated 70% bottom ash samples 0 curing
days
4.4 Consolidated undrained compression test results for 75
normally consolidated 70% bottom ash samples 28
curing days
4.5 Consolidated undrained compression test results for 77
normally consolidated 30% bottom ash samples 0
curing days
4.6 Consolidated undrained compression test results for 78
normally consolidated 30% bottom ash samples 28
curing days
4.7 Critical state line for FA-BA mixtures with 70% bottom 85
ash at 0 curing day
4.8 Critical state line for FA-BA mixtures with 70% bottom 85
ash at 28 curing day
4.9 Critical state line for FA-BA mixtures with 30% bottom 86
ash at 0 curing day
xvii
FIGURE NO. TITLE PAGE
4.10 Critical state line for FA-BA mixtures with 30% 86
bottom ash at 28 curing day
xviii
LIST OF SYMBOLS
BA - Bottom ash
E - Modulus of elasticity
FA - Fly ash
H - The slope of the Hvorslev on the q-p’ plane
M - The slope of critical state line on the q –p’ plane
p’ - Mean normal effective stress
q - Deviator stress
qp - Deviator stress at peak
qc - Deviator stress at critical
Υ - Specific volume = 1+ e
Γ - Intercept of critical state line with the υ-axis
λ - The slope of normal consolidated line in υ – p’ plane
c’ - Internal friction angle at critical state
p - Internal friction angle at peak
εp - Axial strain at peak
εc - Axial strain at critical state
1
CHAPTER 1
INTRODUCTION
1.1 Background
One of the sources to produce electricity is coal. The major problem of the
coal combustion based power plant is producing huge quantities of solid waste. The
coal combustion residues (CPP’s) including silica (61%), alumina (22%) and iron
oxide (7%), which make up of 90% of the ash. The others element are calcium (Ca),
magnesium (Mg), sodium (Na), kalium (K) and sulfur (S) (Chang et al. 1979,
Adriano et al. 1980, Saxena et. al. 1998a).
Coal-burning power plant has produced a large volume of coal ash and
bottom ash. The ratio of production between fly ash and bottom ash is 80:20 by
weight (ACAA 2001). Most of the CCRs are disposed off as slurry to ash ponds. It is
due to low in cost as well as easily operated. The solid CCRs are collected and mixed
with water, and the slurry is pumped through a series of pressurized pipes to ash
ponds. (Asokan et al. 2004).
In Malaysia, the study of the coal ash and bottom ash is still limited. The
disposal problem of coal ash and bottom ash is becoming critical by the times going.
2
Thus, some studies have been made to utilize the fly and bottom ash as replacement
material in geotechnical works. For instance, fly and bottom as can be used in soil
replacement, soil embankment even in material filling (Abdul Rahim et al. 2012).
1.2 Problem of Statement
There is limited study on local coal ash compared to other countries. The
local companies do not have enough information and laboratory evaluation on fly
and coal ash. The ash pond for disposing the coal combustion products becoming
lesser and the authorities have to find other alternative routes to solve coals ash
accumulative problems.
The use of fly and bottom ash as the substitution in geotechnical works is still
in essential stage. Hence, the study of the strength characteristic of the fly and bottom
mixture is significant and critical. Apart from this, the appropriate proportion of fly
and ash mixtures is also important to maximize the strength of the mixtures.
Respective mixture may be used for highway embankment construction, reclamation
and others geotechnical works.
3
1.3 Objective of the Study
The purpose of the study is to investigate the effect of bottom ash content on
the strength characteristics of fly ash and bottom ash mixtures. Thus, the following
study objectives have been formulated:
1. To evaluate the morphology and chemical properties of different FA:BA
mixtures at various curing period.
2. To determine the modulus of elasticity and strength parameters of
different FA:BA mixtures
3. To evaluate the strength behavior of different ratio of FA: BA mixtures at
various curing periods under undrained condition using critical state
method.
1.4 Scope and Limitation of Study
The study is focusing the morphology, chemical and strength characteristic of
fly ash and bottom ash mixtures from the Tanjung Bin power plant in Johor,
Malaysia. The mixtures used in this study is including, 30% and 70% of the bottom
ash in the mixtures. The curing periods of the samples concerned were 0 and 28 days.
The morphology characteristic had been tested by scanning electron microscopy, the
chemical properties tested by x-ray fluorescence and the strength test was carried out
using consolidation undrained triaxial test.
4
1.5 Significant of the Study
The result that obtained from this study can be determined the
suitability of fly and bottom mixture ratio in beneficial the geotechnical
works. The variety of strength that obtained can investigate the suitability in
different scope of geotechnical works such as soil replacement, soil
embankment or back filling materials.
92
REFERENCES
Abdul Rahim Awang, Aminaton Marto and Ahmad Mahir Makhtar (2012).
Morphological and Strength Properties of Tanjung Bin Coal Ash Mixtures for
applied in Geotechnical Engineering Work. International Journal on
Advanced Science Engineering Information Technology Vol.2, pp 55-62
ACAA (American Coal Ash Association) (2003) Fly Ash Facts for Highway
Engineers. Technical Report ACAA, USA.
Adriano, D.C., Page, A.L., Elseewi, A.A., Chang, A.C. & Stranghan, L. (1980):
Utilisation and Disposal of Fly Ash and Other Coal Residues Interrestrial
Eco System: A Review. Environmental Quality, 9, 333.
Asokan Pappu, Saxena Mohini, Aparna Asokan, Shyam R. Asoletar
(2004).Characteristics variation of coal combustion residues in an Indian ash
pond. Waste Management and Research, v 22, n 4, p 265-275
ASTM (American Standard Testing Method) (2004) .Standard Specification for Fly
Ash and Rawor Calcined Natural Pozzolan for Use as a Mineral Admixture
in Portland Cement Concrete. ASTM, USA.
ASTM C618-98, 1998, Standard Specifications for Coal Fly Ash and Raw or
Calcined Natural Pozzolans for Use as a Mineral Admixture in Concrete.
1998 Annual Book of ASTM Standards, vol. 4.02 (concrete and aggregates),
pp. 293_295, West Conshohocken, PA, USA.
93
Briaud J.L. (2001) Introduction to Soil Modulus, Geotechnical News, June 2001,
BiTech Publishers Ltd, Richmond, B.C., Canada.
Bumjoo, K., Prezzi, P. and Salgado, R. (2005). Geotechnical Properties of Fly and
Bottom Ash Mixtures for Use in Highway Embankments. Journal Of
Geotechnical And Geoenviromental Engineering, 914-924
Carlton, C. Wiles (1996). Municipal Solid Waste Combustion Ash: State of The
Knowledge. J. Hazard. Mater., 47, 325–344.
Carrier, W. D., III. (2000). “Compressibility of a compacted sand.” J. Geotech.
Geoenviron. Eng. 126(3), 273–275.
Chakraborty, T.K. and Dasgupta S.P.(1996). Randomly reinforced fly ash as
foundation material, Proc. Indian Geotechnical Conf., Madras. Vol. 1, pp.
231–235
Chang, A.C., Lund L.J., Page A.L. & Warneke, J.E. (1979): Physical properties of fly
ash amended soil. Journal of Environmental Quality, 6, 267–270.
Das, Braja M. (2011), Principles of Foundation Engineering, 7th
edition, Cengage
Learning.2011
DiGioia, A. M., and Nuzzo W. L. (1972). Fly Ash as Structural Fill. Proc., American
Society of Civil Engineers, Journal of the Power Division, New York.
Eisele, T.C. , Kawatra S.K. & Nofal A. (2004). Comparison of Class C and Class F
Fly-Ashes as Foundary Sand Binders and The Effectivenessof Accelerators in
Reducing Curing Time. Mineral Processing and Extractive Metallurgy
Review: An International Journal, 25:4, 269-278
Faber, J.H. and Digioia A.M., (1976). Use of Ash in Embankment Construction,
Transportation research record, Use of waste materials and soil stabilization,
National Academy of Sciences, Washington DC, No. 593, pp. 13–19.
94
Head, K.H. (1986). Manual of Soil Laboratory Testing Volume 3. Pentech Press
Limited
Huang, W. H., (1990), The Use of Bottom Ash In Highway Embankments, Subgrades,
And Sub-bases, Joint Highway Research Project, Final Report,
FHWA/IN/JHRP-90/4, Purdue University, W. Lafayette, Indiana.
Huang, H. W. and Lovell, C. W. (1993), Use of Bottom Ash and Slags in Highway
Construction, Fourth International Symposium on the reclamation, Treatment,
and Utilization of Coal Mining Wastes, Karakow, Poland, Sep., pp. 358-368.
Indraratna, B., Nutalaya P., Koo K.S. and Kuganenthira N. (1991)., Engineering
behaviour of a low carbon, pozzolanic fly ash and its potential as a
construction fill, Can. Geotech. J., 28, 542–555.
Kaniraj,S.R. and Gayathri, V. (2004). Permeability and Consolidation Charcteristics
of Compacted Fly ash. Journal of Energy Engineering, Vol. 130, No.1.
Kim, B., Prezzi, M., and Salgado, R. (2005). Geotechnical Properties of Fly and
Bottom Ash Mixtures for Use in Highway Embankments. J. Geotech.
Geoenviron. Eng., 131(7), 914–924.
Kim, B.J., Yoon, S.M., and Balunaini, U. (2006). Determination of Ash Mixture
Properties and Construction of Test Embankment –Part A. Joint
TransportationResearch Program, Final Report, FHWA/IN/JTRP-2006/24!
Purdue University, W. Lafayette, Indiana.
Martin, J.P., Collins R.A., Browing J.S. and Biehl F.J. (1990). Properties and use of
fly ashes for embankments, J. Energy Engng, 116, 71–75.
Marwa, B. A. Critical State Of Fly Ash-Bottom Ash Mixture. Master project.
Universiti Teknologi Malaysia; 2010
McKerall, W. C., Ledbetter, W. B., and Teague, D. J. (1982). Analysis of Fly Ashes
Produced in Texas. Texas Transportation Institute, Research Rep. 240-1,
Texas A&M University, College Station, TX.
95
Meegoda, Jay N.; Shenyan Gao; N. M. A. Al-Joulani; and Liming Hu (2011): Solid
Waste and Ecological Issues of Coal to Energy. Journal of hazardous, toxic,
and radioactive waste,99-107
Muhardi, Aminaton Marto, Khairul Anuar Kassim, Ahmad Mahir Makhtar, Lee Foo
Wei, Yap Shih Lim (2010), Engineering Characteristics of Tanjung Bin Coal
Ash, EJGE, volume 15, 1117-1129
Naganathan, S., Subramaniam, N. & Mustapha, K.N. (2012), Development of Brick
using Thermal Power Plant Bottom Ash and Fly ash. Asian Journal of Civil
Engineering (Building and Housing) Vol. 13 No. 1 pp. 275-287.
National Research Council. (2006). Managing Coal Combustion Residues in Mines.
National Academies Press, Board on Earth Sciences and Resources,
Published, National Academies, (U.S.).
NETL (National Energy Technology Laboratory), (2006). Clean Coal Technology:
Coal Utilization By-Products. Washington DC; Department of Energy Office
of Fossil Energy; Topical report No. 24.
Pandian, N.S. and S. Balasubramonian (2000). Leaching Studies on ASTM Type F
Fly Ashes by zn Accelerated Process Method, J. Testing Evaluation, ASTM,
28, 44–51.
Pandian, N.S. (2004). Fly Ash Characterization with Reference to Geotechnical
Applications, Journal of Indian of Institute of Science, Vol. 84, p 189-216.
Roszczynialski, W. (2002). Determination of Pozzolanic Acticity of Materials by
Thermal analysis. Journal of Thermal Analysis and Calaorimetry, Vol. 70,
p.387-392.
96
Roy,W. R., Thiery, R. G., Schuller, R. M., and Suloway, J. J. (1981). Coal Fly Ash:
A Review of The Literature and Proposed Classification System With
Emphasis on Environmental Impacts. Environmental Geology Notes, No. 96,
Illinois State Geological Survey, Champaign, IL.
Saxena, M., Asokan, P. & Aparna, A. (1998a): Effect of Fly Ash on Clay Soil. Clay
Research,17, 109–114.
Singh, S.R. and Panda A.P. (1996)., Utilization of fly ash in geotechnical
construction, Proc. Indian Geotechnical Conf., Madras, Vol. 1, pp. 547–550.
Taylor, H. F. W.(1990) Cement Chemistry, Academic Press, London, pp. 231_237.
Tri Utomo,S.H. (1996). The Effects of Time on Properties of Pulverised Fuel Ash.
PhD Thesis, University of Newcastle upon Tyne, UK (Unpublised).
Tsen, M. Z., (2008) The Properties of Fly Ash-Based Geopolymer Mortar with
Potassium Based Alkaline Reactor. Unpublished B.Eng Thesis, Curtain
University of Technology.
U.S. Navy (1986). Design Manual – Soil Mechanics, Foundations and Earth
Structures. NAVFAC DM-7, Dept. of the Navy, Washington, D.C.
Waseem, M., Prashant A., Chandra, S. (2004).Single Element Test Predictions for
Stress-Strain Behaviour of Panki Fly-Ash. Department of Civil Engineering,
Indian Institute of Technology Kanpur, India-208016.
Whitlow, R. (2001). Basic Soil Mechanics. Forth edition. Pearson Education Ltd.
