PERPUSTAKAAN UMP.
THE UND1.AII 100 ID Ill ID 111 11111 )FT CLAY REINFORCED 0000092394 VIETER OF
GROur liuFlolvi ASh COLUMN
RAJA NUR SHAHIRA BT. RAJA SHARUDIN
A thesis submitted in fulfillment of the requirement for award of the degree of
B. ENG (HONS) CIVIL ENGINEERING
Faculty of Civil Engineering & Earth Resource
UNIVERSITI MALAYSIA PAHANG
JUNE 2014
ABSTRACT
Soft clay soil can be categorized as problematic soil. A constructing structure which is constructed on a poor ground such as soft clay can affect the stability and settlement of the structure. Soft clay consists of a low shear strength, low ability permeability and high compressibility characteristic and that are the major reasons why a careful design analysis could be taken for any structure built on it. There are various method that been approach to improve the strength of the soft clay soil and the most popular method that is being used in the construction field is stone column. In another view, large production of bottom ash from coal burning in Malaysia has resulted in waste problem. This study is to present suitability in terms of shear strength by using bottom ash to replace sand or stone in columns for ground improvement technique using the laboratory scale model. As we know that sand is one of the non-renewable materials so by utilize by-product or waste which is bottom ash, we can reduce utilization of sands and at the same time we can prevent pollution and sand from disposing. The first stage is to determine the physical and mechanical properties, the test that is being conducted to determine these terms are Atterberg limits, specific gravity, direct shear test, constant head permeability test, standard compaction test and hydrometer test. Kaolin is used as soil sample and bottom ash as the reinforced columns. In the second stage of the study, consolidated kaolin as soft clay were reinforced with group of 3 bottom ash columns and tested for shear strength using Unconfined Compression Test.
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ABSTRAK
Tanah lembut adalah tanah yang dikategori dalam tanah yang bennasalah. Satu struktur pembmaan yang dibina di atas tanah lembut seperti tanah hat lembut boleh menjejaskan kestabilan dan pemendapan struktur tersebut. Ciri-ciri tanah hat lembut terdiri daripada kekuatan ricih yang rendah, keupayaan kebolehtelapan yang rendah dan ciii kebolehmampatan yang tinggi dan mi adalah sebab-sebab utama mengapa analisis reka bentuk yang terliti perlu diambil kira untuk apa-apa struktur yang dibina di atasnya. Terdapat pelbagai kaedah yang boleh digunakan untuk meningkatkan kekuatan tanah hat lembut dan kaedah yang paling popular yang digunakan dalam bidang pembinaan adalah tiang batu pengeluaran abu bawah dalam kuantiti yang banyak daripada pembakaran arang batu di Malaysia telah menyebabkan masalah bahan buangan. Kajian mi adalah untuk membentangkan kesesuaian dari segi kekuatan ricih dengan menggunakan abu bawah untuk menggantikan pasir atau barn dalam ruangan teknik pembaikan tanah menggunakan model skala malunal. Seperti yang kita tahu bahawa pasir adalah salali satu daripada bahan-bahan yang tidak boleh diperbaharui, oleh demikian, dengan menggunakan bahan buangan seperti abu bawah, kita boleh mengurangkan penggunaan pasir dan pada masa yang saina kita boleh mencegah pencemaran udara dan dapat mengelakkan pasir daripada pupus. Penngkat pertama adalah untuk menentukan sifat-sifat fizikal dan mekanikal, ujian yang sedang dijalankan untuk menentukan syarat-syarat mi adalah ujian had Atterberg, ujian graviti tentu, ujian serakan (hidrometer), ujian analisis ayakan kering, ujian kebolehtelapan, ujian ricih dan ujian pemadatan tanah. Kaolin digunakan sebagai sainpel tanah dan abu bawah akan diletakkan didalam lubang yang di korek sebagai teknik pembaikan tanah. Pada peringkat kedua kajian mu, kaolin sebagai sampel tanah hat lembut telah diperkukuhkan dengan melakukan tiga tiang abu bawah pada sampel yang disediakan dan diuji untuk kekuatan ricih dengan menjalankan uji kaji kuat tekan bebas.
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TABLE OF CONTENT
Page
DECLARATION
DEDICATION
ACKNOWLEDGEMENT
ABSTRACT
ABSTRAK
TABLE OF CONTENT viii
LIST OF TABLES
LIST OF FIGURES xiii
LIST OF SYMBOLS xv
LIST OF ABBREVIATION xvi
CHAPTER 1 INTRODUCTION
1.1 Background of Study 1
1.2 Problem Statement 4
1.3 Objective 5
1.4 Scope of Study 6
1.5 Significance of Study 7
CHAPTER 2 LITEREATURE REVIEW
2.1 Introduction 8
2.2 Soft Clay 8
2.2.1 Compressibility and Consolidation 10
2.2.2 Shear Strength 11
2.3 Bottom Ash 12
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2.3.1 Particle sizes distribution 14
2.3.2 Specific Gravity 16
2.3.3 Compaction 17
2.3.4 Shear Strength 18
2.3.5 Permeability 19
2.4 Utilization of Bottom Ash 20
2.5 Ground Improvement of Granular Column 22
2.6 Sustainability in Construction 26
2.7 Small Scale Modelling 27
CHAPTER 3 RESEARCH METHODOLOGY
3.1 Introduction 31
3.2 Laboratory test to determine of physical and mechanical 33
properties
3.2.1 Atterberg limit 33
3.2.2 Specific gravity test 34
3.2.3 Grain Sieve Analysis Test 36
3.2.4 Standard Compaction Test 38
3.2.5 Constant Head Permeability Test 39
3.2.6 Direct Shear Test 40
3.3 Reinforced Soft Clay with Group Bottom Ash Column 41
3.3.1 Preparing Sample 41
3.3.2 Installation of Bottom Ash Columns 43
3.4 Unconfined Compression Test 46
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CHAPTER 4 RESULT AND DISCUSSION
4.1 Introduction 48
4.2 Summary of Kaolin and Bottom Ash 49
4.3 Physical Properties 50
4.3.1 Atterberg Limit 50
4.3.2 Specific Gravity 52
4.3.3 Particles Size Distribution 53
4.4 Mechanical Properties 55
4.4.1 Compaction 55
4.4.2 Permeability 57
4.4.3 Direct Shear Strength 57
4.5 Reinforcing Soft Clay with Bottom Ash Column 59
4.5.1 Stress-Strain Behaviors under Axial Load 59
4.5.2 Effect of Bottom Ash Column on Shear Strength 61
4.5.3 The Effect of Area Replacement Ratio 64
4.5.4 The Effect of Penetration Ratio 68
4.5.5 Effect of Column Penetration Ratio 71
CHAPTER 5 CONCLUSION AND RECOMMENDATION
5.1 Introduction 74
5.2 Conclusion 74
5.3 Recommendation 77
REFERENCES 79
APPENDIX
A Specific Gravity Test Result 82
B Atterberg Limit Test Result 83
C Compaction Test Result 84
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D Falling Head Test Result
86
B Constant Head Test Result
87
F Hydrometer Test Result
88
G Sieve Analysis Test Result
89
LIST OF TABLE
Table No. Title Page
2.1 Classification by particle size based on 14 BS1377:1975
2.2 Comparison of bottom ash specific gravity value 16
2.3 Result of direct shear test of bottom ash 19
2.4 Classification of soil according permeability value 20
2.5 Utilization of bottom ash in tones 21
2.6 Effect of area replacement ratio on undrained 23 shear strength
3.1 Sample with variables of bottom ash 42 installation
3.2 Detail on densif'ication process for installing 43 bottom ash column for diameter 6 mm and 10 mm
4.1 Summary of kaolin clay properties 47
4.2 Summary of bottom ash properties 48
4.3 Comparison of bottom ash specific gravity 51 values
4.4 Maximum deviator stress and axial strain value at 58 different area replacement ratio and different height penetration ratio
4.5 Improvement Shear strength 60
4.6 Result of unconfined compression test 61
4.7 Correlation equation and cohesion value 71
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LIST OF FIGURES
Table No. Title Page
1.1 Installation of vertical granular column 2
2.1 Quaternary sediment in Peninsular Malaysia 10
2.2 (a) Fly Ash (b) Bottom Ash. 13
2.3 Particle size distribution of fly ash and bottom ash 15
2.4 Compaction curves of Tanjung Bin bottom ash 18
2.5 Column arrangement 24
2.6 Deviator stress to failure for various-column 25 penetration ratio
2.7 Effect of ratio of column height to diameter 26
2.8 Sketch of custom built consolidation cell 28
2.9 Model test on single and group of stone column 29
3.1 Flow chart of the activities then being conducted 32 for this project
3.2 Liquid Limit and Plastic Limit Test 34
3.3 Apparatus for Specific Gravity Test 35
3.4 Sieve Shake Analysis 38 3.5 Apparatus of Hydrometer 38 3.6 Apparatus for Compaction Test
3.7 Mixture Machine 39 3.8 Apparatus of Constant Head Permeability 40 3.9 Assembly of 60mm Shear Box 41 3.10 Customized mould set for 50 mm diameter and 42
100 mm height
3.11 The procedure of preparation sample 43 3.12 Detail column arrangement 3.13 Apparatus for the Unconfined Compression Test 47 4.1 Graph of penetration versus moisture content 51
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xlv
4.2 Plasticity Chart (ASTM D2487) 52
4.3 Particles size distribution of kaolin 54
4.4 Particles size distribution of bottom ash 55
4.5 Graph of compaction test of kaolin 56
4.6 Graph of compaction test of bottom ash 56
4.7 Graph of shear stress versus normal stress 58
4.8 Deviator stress versus axial strain at failure for 1.44 % area replacement of bottom ash column at 60 different penetration ratio
4.9 Deviator stress versus axial strain at failure for 4.0 % area replacement of bottom ash column at 61 different penetration ratio
4.10 Shear strength versus area replacement ratio 64
4.11 Correlation graph of shear strength with area 65 replacement ratio
4.12 Improvement undrained shear strength with area 66 replacement
4.13 Upper limit and lower limit graph of correlation improvement undrained shear strength with area 66 replacement ratio
4.14 Mode of failure of sample with 1.44 % area 67 replacement ratio
4.15 Shear strength versus height penetration ratio 68
4.16 Correlation graph of shear strength with height 69 penetration ratio
4.17 Improvement undrained shear strength with height 70 penetration ratio
4.18 Correlation graph of improvement undrained shear 70 strength with height penetration ratio
4.19 Effect of ratio column height to diameter on shear 72 strength
4.20 Upper limit and lower limit graph of correlation effect ratio column height to diameter on 72 shear strength
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LIST OF SYMBOL
Ac Area of a column
As Area of the sample
HC Height of a column
HS Height of a sample
Ve Volumes of the column
Vs Volumes of the sample
De Diameter of column
Si Immediate settlement
Sc Primary consolidation
Shear strength of the soil
ci Effective normal stress
Cohesion.
WL Liquid limit
WP Plastic limit
Ip Plastic index
Wopt Optimum moisture content
qu Deviator stress
su Undrained shear strength
5u Improvement of undrained shear strength
Pd Dry density
Correlation cohesion
LIST OF ABBREVIATIONS
BA Bottom Ash
FA Fly Ash
MSW Municipal Solid Waste
USCS Unified Soil Classification System
AASHTO American Association of State Highway and Transportation Officials
ACAA American Coal Ash Association
ML Low plasticity silt
SW Well graded sand
UCT Unconfined compression test
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF STUDY
The development of urban area is increasing quickly around the world nowadays,
there is a vast growth in the development of industrial, housing and other infrastructure
facilities due to the increase of population. The government wants to make sure that all of
the people in this country can live in a comfortable place. However, due to the limited
availability of construction sites, prices of land keep on increasing. The developers take an
effort to construct a building on a soft soil which is more economical.
Often project sites are located in areas with soft or weak soils. Soft soil can be
categorized as problematic soil. The low strength and high compressibility characteristic
the soil had are the major reasons why a careful design analyis could be taken for any
structure built on it. Settlement and the stability of the structure can be effected if the
structure is constructed on a poor ground. Therefore, cracking on main structure or
pavement could happen if the structures such as building, road pavement, runways,
embankment, dam and shallow foundation are constructed on low strength of soil. This can
induce a high cost to reconstruct or repair the engineering structure,,,,
I
2
The ground improvement is necessitated to modify the soil properties. Ground
improvement techniques are used to prepare the ground for new construction projects and
to reduce the risk of liquefaction in areas of seismic activity. Without a properly interpreted
soil improvement, hazard which lie on the ground beneath the site cannot be known.
Various techniques had been used to improve the soft soil, for example reinforcement with
geosynthetics, lime treatment, acceleration of pre-consolidation using pre-fabricated
vertical drains, and the most popular method is a vertical granular column.
The method of vertical granular column consists of forming a vertical hole in the
ground which are filled with compacted crushed stone, gravel and sand or a mixture which
shown in Figure 1.1 to improve the strength of the soft soil. In general, vertical granular
columns are either constructed as fully penetrating through a clayey soil layer overlying a
firm stratum or partially penetrating with their tips embedded within the clayey soil layer
(Shahu and Reddy, 2011).
Figure 1.1: Installation of vertical granular column
Source: Kempfert and Gebreselassie, 2006
3
The method of the vertical granular column proven that installation of the sand
column had successfully and effectively, improves bearing capacity of weak soft soil,
reduces the post-construction settlement of the structure built and reduction in total
settlement, reduce the liquefaction potential of clean sands, improves the stability of the
embankment and natural slopes, and accelerates the consolidation process (Castro and
Sagaseta, 2008). The columns act as vertical drains which reduce the path length for the
dissipation of excess pore water pressure that generated during loading. Therefore, the
consolidation process became more faster (Maakaroun et al., 2009).
Kumar and Stewart (2003) stated that properties of sand are similar to a properties
of bottom ash. As we know that sand is a non-renewable material, there is a good
opportunity to reuse waste of bottom ash as a replacement material in sand column. The
physical properties of bottom ash are porous, course, granular, grayish and glassy. Bottom
ash that is being used in this study is collected at Tanjung Bin Power Plant in Pontian,
Johor. Tanjung Bin Power Plant has produced 180 ton/days of bottom ash and 1620 ton/day
fly ash from 18000 ton/day of coal burning (Muhardi etal., 2010).
By recycling and utilize the bottom ash as a by-product to replace sand in a vertical
granular column have attracted attention in a construction field to fulfill the current interest
in long term and sustainable development. Thus, with the similar properties as sand, bottom
ash is a suitable material to be used to substitute in a vertical granular column. At the same
time, we can reduce the cost of construction and reduce the problem of disposal of waste
material as bottom ash.
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1.2 PROBLEM STATEMENT
Structures are meant to stand strong for many years to come and importantly it can
provide a great strength to support the load within the structure In the soil properties, soft
clays are the unstable soil condition and believed to be the major circumstances for any
structure to be built on it. By gaining or having the knowledge about the engineering
characteristics of soft clay soil and studied into consideration as deep understanding of the
analysis could help people which involved in this field to understand how critical the soil
could become to the structure. In construction, building that built on the soft clay soil is
adaptable to be constructed with weak foundation and for sure it can cause a structural
failure.
Soft clay consists of a low shear strength, low ability permeability and high
compressibility characteristic and that are the major reasons why a careful design analysis
should be taken for any structure built on it. Soil which has a weak condition such as soft
clay, the stifthess of the soil could easily be affected and this can make the soil become
weak in strength and could not support high load on it. It will be more dangerous if the
structure built on a weak condition of the soil and at the same time it can cause failure of
the structure.
Power plant produces both bottom ash (BA) and fly ash (FA). Bottom ash is
recovered from the combustion chamber of the inorganic material as well as some
unburned organics while fly ash is the particular removed from the gaseous emissions.
Considering , both types of ash together, Municipal Solid Waste (MSW) combustion
typically achieves a 75 % reduction in material by weight (and 95 % reduction by volume)
Thus 25 % of the original mass are ash, with high density, of about 1200 to 1800 ib/yd3..
The sustainable amount of ash disposed in the landfills generates an environmental
Pollution from time to time
5
In the previous study, bottom ash has been identified as a coarse, with grand sizes
spanning from fine sand to fine gravel. By recycling or reuse bottom ash as a replacement
sand in a sand column can reduce utilization of non-renewable material as sand in site in
order to save money as well to keep the environment safe The cost of construction also can
be reduced and this could be one of the techniques in achieving the sustainable
development in the construction industry. -
1.3 OBJECTIVE
This study it to determine the degree of improvement made for use of bottom ash
columns in soft clay in a laboratory scale model. Soft clay has been represented by
compacting kaolin. The objectives that had been identified are:
a) To determine physical and mechanical properties of bottom ash and kaolin
clay sample.
b) To determine the shear strength of soft clay reinforced with group bottom
ash column.
C) To establish correlations relating undrained shear strength with various
dimensions.
1.4 SCOPE OF STUDY
The scope of study includes the process to identify the physical and mechanical
properties of kaolin and bottom ash. Several laboratory tests are being carried out and the
test that is being conducted is to determine the physical and mechanical properties of kaolin
are liquid limit, specific gravity and hydrometer test. For physical and mechanical
properties of bottom ash are specific gravity test, dry sieve test, direct shear test, constant
head permeability test and standard compaction test.
Subsequently, this study also covers the determination of shear strength of soft clay
reinforced with group bottom ash column. By using one-dimensional test the kaolin clay is
prepared obtained from consolidating kaolin slurry. Five batches of kaolin sample with 50
mm diameter and 100 mm height was prepared. Next, Unconfined Compression Test was
conducted to determine the shear strength of reinforced soft kaolin clay and the test was
following the BS 1377-Part 7:1990.
One batch had 15 samples that are being prepared in this project with two different
diameters (6 mm, and 10 mm) with three different heights of level. For 6 mm diameter,
the height level are 24 mm, 36 mm, and 48 mm while for 10 mm diameter the height level
are 40 mm, 60 mm, and 80 mm. Area replacement ratio (AdA) which is Ac is an area of a
column and A is an area of the sample (1.44 %, and 4 %). The height penetration ratio
(HJH) which is Hc is a height of a column and Hs is a height of the sample (0.4, 0.6, and
0.8). Volumes of bottom ash column (1I) between the volumes of the sample (Vs) for 6 mm
diameter are 0.35 %, 0.52 %, and 0.69 % while for 10 mm diameter are 1.6 %, 2.4 %, and 3.2%.
7
1.5 SIGNIFICANCE OF STUDY
The aim of this study is to identify the improvement shear strength of soft clay after
reinforced with group of three bottom ash columns in a small scale model. Thus, there are
some laboratory experiment were carried out to determine whether the bottom ash is a
suitable material for replacing sand or stone in columns for ground improvement technique.
The use of bottom ash column material to replacing sand or stone was not only
increased the bearing capacity of soft soil, it also reduces the settlement of the structure's
foundation. Without question, this would increase the significantly the availability of
marginal sites for cheaper and long term construction.
Besides that, it can cut of the utilization of non-renewable material which is sand
and also reducing the waste problem of bottom ash which currently was disposed in a huge
quantity into the landfill. Other than that, it was expected by reused bottom ash as a
replacement of sand or stone in columns can reduôe cost because bottom ash is .a waste
material from coal combustion, compared to the expensive sand or stone.
In this developing country, we should require to have effort to recycle or reuse
material that can save costs but at the same time it can keep the environment safe from
polluted so that it can last long in future. This study was hopefully being part of the effort
to help our country be more developed and success in every sector in future.
CHAPTER 2
LITERATURE REVIEW
2.1 INTRODUCTION
In today's construction industry, Geotechnical engineers usually faced a problem
where they have to construct a building on a very complex and problematic soil This
problematic soil is .soft soil. This situation had led to the findings and applications of
various types of ground improvement method such as sand column. Sand column that had a
similar properties as bottom ash.. To save our environment from pollution, we can take
initiative such as to reuse or recycle waste materials such as bottom ash to replace and
substitute sand in the vertical granular column. Other than that, we can reduce costs and the
land use is optimized.
2.2 SOFT CLAY
According to Liu and Evett (2005), particle sizes of soft clay are less than about
0 OO2mrn or it can easily break down to this size Soft clay, is the finest of all and even it
can only be clearly monitored by using microscopic tools. Soft clay is part of fine grained
soil, with soil grains finer than 0.075 mm Unified Soil Classification System (USCS) has
stated that the soft soil is categorized as small particle soil that 50 % pass sieve No 200
8
Specification US (0.075 mm). A structure that built on soil is exposed to settlement,
however, the possibility for the settlement occur are very high for the soft soil condition.
Excessive settlement is tipped to be a big problem as it often exceeds the permissible limits
(Craig, 2004).
Soft soils can be defined as clay or silt which is geologically young and under a
constant condition since its formation to its own weight yet not undergone significant
secondary consolidation. Moreover, the soils are just capable of carrying its own
overburden weight and ay imposed additional load will result in relatively large
deformation. Soil which had not completed the consolidation under their own weight are
also can be included in this group (Kempfert and Gebreselassie, 2006).
In Peninsular Malaysia, the coastal deposits have been classified as quaternary
deposits from Cenozoic era which shown in Figure 2.1 as being shown by Jamal et al.
(1997). A few type of soil material that can be found in the quaternary deposit which are
clay, silt, sand, seashell and decayed wood. The quaternary deposit is widespread along the
coastline. The thick deposit of the clay occurs near to the coastal area and major river
mouth. According to Huat (1994), the thickness is around ranged 5 in to 30 m.
Characteristic of soft clay is more alike to a typical characteristic of soft soil which is high
compressibility, low shear strength and low permeability. In this study, a few past
researcher that had conducted this study to identify the engineering behavior of the, soft clay
in Peninsular Malaysia such as Kiang based on the geotechnical site investigation (Tan et
al., 2005), Bukit Raja on the determination of undrained shear strength (Jamal et al.,
1997). Hence, it indirectly showed that the appropriate site for construction is so limited
and the utilization of ground improvement technique is important to enhance the
mechanical properties of the soft soil in Malaysia.
4e.r .'fls
7_ .
Figure 2.1: Quaternary sediment in Peninsular Malaysia
Source: Chin and Gue (2000)
2.2.1 Compressibility and Consolidation
A deformation and compression will be occurring when a load is applied on the
saturated soil. Water will be dissipated out of the soil, the particles of the soil will move
closer and the density will increase. Wesley (2010) has stated that, consolidation is a
Process to increase stress and causing squeeze out of water. Consolidation can be divided
into two parts which are immediate settlement (Si) and primary consolidation (Sc). The total
settlement is expressed as in equation (2.1).
S = Si+Sc+Ss (2.1)
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I 1
Immediate settlement in clay happens when air is expelled from the voids upon
application of stress on saturated soil The properties of clay which is low permeability can
lead to the less drainage of water in clay. The elastic displacement theory is being used to
estimate the immediate settlement (Tan et al., 2005).
Primary consolidation is a process when the excess pore water pressure would cause
water to dissipate and further settlement occurs in clay. According to Tan et al. (2005), the
volume of soil changes as the pore pressure is eliminated and in turn, an effective stress
exerts in the soil. The process conducted continuously until the excess pore water pressure
is completely drained out and the loads were carried by the soil skeleton. Oedometer test
also known as one-dimensional consolidation test which is conducted to estimate the
amount of the settlement and the time needed for the consolidation process.
Based on the statement that being carried out from Craig (2004), the secondary
consolidation is based to the gradual rearrangement of the clay particles into a more stable
configuration. The deformation of soil skeleton is actually caused by the settlement and this
process is much longer compared to primary consolidation.
2.2.2 Shear Strength
Shear strength defines as the soil's ability to resist sliding along the internal surface
within a mass of the soil. The estimation of shear strength can be expressed by the
Coulomb equation (Liu and Evett, 2005):
t = tan + C
(2.2)
'r is define as a shear strength of the soil, o is defined as an effective normal stress,
while 0 defines as a cohesion.
12
By conducting an unconfined compression test, cone penetration test, field vane test
or standard penetration test can predict the shear strength of the soft clay (Jung et al.,
2010). Unconfined compression strength of clay which less than 50 kPa is classified as soft
clay and clay which less than 25 kPa is classified as very soft clay.
According to Tan et al. (2004), Klang clay is being categorized as soft soil because
the undrained shear strength (Su) was in the range of 18 kPa to 50 kPa. Based on a study of
the past researcher Jamal et al. (1997) stated that, the value of the undrained shear strength
in Bukit Raja in Kiang area is found the range is around 6 kPa to 23 kPa. Hence, the soil at
Bukit Raja is classified as very soft clay.
2.3 BOTTOM ASH
Fly ash and bottom ash produced as a by- product material from coal combustion in
coal fired power plant.. This material is actually a group of highly scatting tiny particles and
made up of silicon oxide glass spheres. It has two different shapes based on sizes and shape
of the particles. Fly ash is in spherical particles while for bottom ash is in irregular particles
(Tai Lv et al., 2009).
In Figure 2.2(a) shows that fly ash is consisting of fine-grained sizes range between
fine silt and fine sand while bottom ash which shown in Figure 2.2(b) consists of coarse
angular particles ranging in size from sand to small gravel. Both materials have a unique
morphological characteristic and it is different from the typical soils.
