IMPROVEMENT OF GEOTECHNICAL PROPERTIES OF

LOCAL CLAY BY USING FLY ASH

Muhammad Wazizi Hamzar b. Abdul Aziz

Bachelor of Engineering with Honours

(Civil Engineering)

2009

UNIVERSITI MALAYSIA SARAWAK

BORANG PENGESAHAN STATUS TESIS *

JUDUL: IMPROVEMENT OF GEOTECHNICAL PROPERTIES OF LOCAL CLAY BY USING FLY ASH

SESI PENGAJIAN: 2008 / 2009

Saya MUHAMMAD WAZIZI HAMZAR B. ABDUL AZIZ

(HURUF BESAR)

mengaku membenarkan tesis * ini disimpan di Pusat Khidmat Maklumat Akademik, Universiti Malaysia

Sarawak dengan syarat-syarat kegunaan seperti berikut:

1. Tesis adalah hak milik Universiti Malaysia Sarawak. 2. Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dibenarkan membuat salinan untuk

tujuan pengajian sahaja.

3. Membuat pendigitan untuk membangunkan Pangkalan Data Kandungan Tempatan. 4. Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dibenarkan membuat salinan tesis

ini sebagai pertukaran antara institut pengajian tenggi.

5. ** Sila tandakan ( ∕ ) di kotak yang berkenaan

SULIT (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan

Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972).

TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh

organisasi/badan di mana penyelidikan dijalankan).

TIDAK TERHAD

Disahkan Oleh:

_______________________ ________________________

(TANDATANGAN PENULIS) (TANDATANGAN PENYELIA)

Alamat Tetap: LOT 1390, LORONG JUARA 1B, DR. PRABIR KUMAR KOLAY

TAMAN SUKMA, PETRA JAYA,

93050 KUCHING, SARAWAK Nama Penyelia

Tarikh : _________________ Tarikh : __________________

√

CATATAN : * Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah, Sarjana dan Sarjana

Muda.

** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa /

organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu

dikelaskan sebagai SULIT atau TERHAD

“ I hereby declare that I have read this report and in my opinion this report is sufficient

in terms of scope and quality for the purpose for award of the Degree of Bachelor of

Engineering (Civil) with Honors ”.

Signature : ………………...…………………...............

Name of Supervisor : DR. PRABIR KUMAR KOLAY

Date : ………………...…………………...............

“I hereby declare that this report is prepared personally with my own effort unless

references that have been cited accordingly in any part of the report”.

Signature : .……………………………...........................

Name of Author : MUHAMMAD WAZIZI HAMZAR BIN

ABDUL AZIZ

Date : ………………...…………………...............

APPROVAL SHEET

This project report attached here to, entitles “IMPROVEMENT OF

GEOTECHNICAL PROPERTIES OF LOCAL CLAY BY USING FLY ASH”

prepared and submitted by MUHAMMAD WAZIZI HAMZAR BIN ABDUL AZIZ

(14628) as a partial fulfillment of the requirement for the Degree of Bachelor of

Engineering with Honours in Civil Engineering is hereby read and approved by:

____________________________________ _______________

DR. PRABIR KUMAR KOLAY Date

SUPERVISOR

IMPROVEMENT OF GEOTECHNICAL PROPERTIES OF LOCAL CLAY BY

USING FLY ASH

MUHAMMAD WAZIZI HAMZAR BIN ABDUL AZIZ

This Thesis Is Proposed To

Faculty of Engineering, University Malaysia Sarawak

For Fulfilment of The Requirements for Bestowal

The Degree of Bachelor of Engineering with Honours

(Civil Engineering)

2009

i

DEDICATION

Dedicated to my beloved family, friends and all the people that have supported,

encouraged and inspired me through good and hard times.

Thanks for everything.

ii

ACKNOWLEDGEMENT

First of all, I would like to express my gratitude to Allah S.W.T, for His

Blessings for me that this final year project can be completed successfully, and for

giving me patience to go through hard times during the completion of this project.

Millions of appreciations to my Supervisor, Dr. Prabir Kumar Kolay, for his

valuable knowledge, guidance and support in my study. Without his help and patient,

this study will not be successful. Thank you for everything.

Next, a special thanks to Mr. Md. Aminur Rahman, and not forgotten Mr.

Simon and also the laboratory technician, Hj. Affandi for sharing their valuable

information and technical support for me to conduct my study.

Finally, thanks to my all lecturers, colleagues and everyone who involved

either directly or indirectly in preparing this report for their diligent help and

respective jobs.

iii

ABSTRAK

Penambahbaikan dan penstabilan tanah jenis lembut sudah lama dipraktikkan

dengan mencampurkan bahan seperti kapur, simen dan ‘pond ash’ untuk

meningkatkan kekuatan tanah tersebut. Terdapat banyak bahan yang dapat juga

digunakan sebagai penstabil untuk meningkatkan kekerasan dan kekuatan tanah liat.

Objektif kajian ini dibuat demi mengkaji perubahan dalam sifat tanah liat tempatan

apabila dicampurkan dengan ‘fly ash’ dari kilang arang batu tempatan. Kajian

dimulakan dengan mengkaji sifat-sifat asas tanah liat tersebut. Selepas itu sampel

disediakan dengan berhati-hati untuk mendapatkan hasil yang konsisten kerana data

daripada kajian ini harus berkaitan antara satu sama lain supaya kesan perubahan

yang ketara dapat dikesan. Standard Proctor Test dan Unconfined Compressive

Strength (UCS) Test adalah method utama yang digunakan dalam kajian ini.

Merujuk kepada data yang telah dianalisis, terdapat peningkatan ketara dalam

kekuatan sampel apabila dicampur dengan ‘fly ash’ sehingga 20 peratus. Sampel

mengandungi 20 peratus fly ash ini mampu bertahan lebih lama dengan muatan

tertinggi dalam ujian tersebut. Kekuatan sampel meningkat sehingga ke hari yang

ketujuh ketika proses ‘curing’ dilakukan, kemudian menurun perlahan-lahan sebelum

kembali meningkat sehingga ke hari yang ke-28. Kesimpulannya, tanah liat tempatan

juga dapat distabilkan dengan mencampurkan ‘fly ash’, dan kajian ini boleh menjadi

langkah pertama dalam kajian penambahbaikan tanah bagi tanah-tanah dalam

Malaysia.

iv

ABSTRACT

Soft soil improvement and stabilization has been widely practised for a long

time by mixing admixtures such as lime, cement and pond ash to increase the

strength of the soil. Different types of admixtures were also used as stabilizers to

improve the stiffness and strength of a clay soil. As for this study, the objective is to

analyze the improvement in local clay soil when being stabilized by using fly ash

from the local coal plant. Tests were first made to study the characteristics of the clay

soil. Then samples are prepared carefully to prevent inconsistencies between them

since the outcome of each tests must be related to each other in order to produce a

significant results. Standard Proctor Test and Unconfined Compression Strength

(UCS) Test are the main tests used in this study. From the analyzed data, there is a

significant increase in strength when the clay sample were mixed with fly ash and the

trend continues until the addition of 20 percent fly ash to the sample. The sample

containing 20 percent fly ash tends to sustain more loads during the compression

tests. The strength of each samples increased until the seventh day of curing, before

gradually decreasing. However, the strength of the samples regained after the

fourteenth day. As a conclusion, local clay can also be stabilized or improved by

using fly ash, and this may become as a starting step for future assessments that

could lead to more soil improvement for ground soil in Malaysia.

v

TABLE OF CONTENTS

Pages

DEDICATION i

ACKNOWLEDGEMENT ii

ABSTRAK iii

ABSTRACT iv

TABLE OF CONTENTS v

LIST OF TABLES ix

LIST OF FIGURES x

LIST OF ABBREVIATIONS xi

LIST OF APPENDICES xiii

CHAPTER 1: INTRODUCTION

1.0 General 1

1.1 Problem Statements 4

1.2 Aim of study 4

1.3 Objectives 5

1.4 Scope and Limitation of Study 5

vi

CHAPTER 2: LITERATURE REVIEW

2.0 General 6

2.1 Clay 7

2.2 Fly ash 9

2.3 Fly ash as a soft-soil treatment admixture 10

CHAPTER 3: METHODOLOGY

3.0 General 15

3.1 Materials 16

3.1.1 Clay soil 17

3.1.2 Fly ash 18

3.2 Procedures 19

3.2.1 Soil sample analysis 19

3.2.1.1 Moisture content 19

3.2.1.2 Hydrometer test 20

3.2.1.3 Liquid Limit (LL), Plastic Limit (PL)

and Plasticity Index (PI) 23

3.2.1.4 Shrinkage limit 25

3.2.1.5 Specific gravity 26

3.2.2 Mixed clay soil and fly ash analysis 27

3.2.2.1 Compaction test 28

vii

3.2.2.2 Unconfined Compression Strength (UCS)

Test 29

CHAPTER 4: DATA ANALYSIS AND DISCUSSION

4.0 General 33

4.1 Moisture content 34

4.2 Hydrometer test 35

4.3 Consistency Limits 37

4.3.1 Liquid Limit 38

4.3.2 Plastic Limit 39

4.3.3 Plasticity Index 40

4.4 Shrinkage limit 41

4.5 Specific gravity 41

4.6 Compaction Test 43

4.7 Unconfined Compressive Strength (UCS) Test 45

CHAPTER 5: CONCLUSION AND RECOMMENDATION

5.0 General 47

5.1 Conclusion 47

5.2 Recommendation 49

viii

REFERENCES 50

APPENDICES 52-149

ix

LIST OF TABLES

Table Page

Table 3.1 Mixture proportion of each sample 27

Table 3.2 Condition of soil according to unconfined compressive

strength, qu (geotech.uta.edu) 30

Table 4.1 Moisture content calculation of the soft clay sample 34

Table 4.2 Particle sizes of the clay and percent finer value 35

Table 4.3 Percentage distribution of the soil sample 37

Table 4.4 Moisture content for samples having different

penetration depths 38

Table 4.5 Moisture content and plastic limit of soil sample 40

Table 4.6 Consistency limits for soil sample 40

Table 4.7 Shrinkage limit of soil sample 41

Table 4.8 Specific Gravity, Gs of clay sample 42

Table 4.9 Specific Gravity, Gs of fly ash sample 42

Table 4.10 The OMC value for every admixture 44

Table 4.11 Average value of Undrained Cohesion Cu 45

Table 5.1 Properties of soil sample 48

x

LIST OF FIGURES

Figure Page

Figure 2.1 Soil-separation Size Limits according to different

standards (After Bush, 1984) 8

Figure 2.2 Soil treated with Class C fly ash 13

Figure 2.3 Image of sample treated with 10% CFBC fly ash and

7 days curing (Reyes and Pando, 2007) 14

Figure 3.1 Work planning diagram 16

Figure 3.2 The location of the clay sample used in this study 18

Figure 3.3 Clay sample undergo hydrometer test for 24 hours 21

Figure 3.4 Hydrometer apparatus 21

Figure 3.5 Oven-dried sample in a shrinkage dish 25

Figure 3.6 50 ml pyknometer used for Sg test 26

Figure 3.7 Compacted sample in cylindrical mold for Standard

Proctor Test 29

Figure 3.8 Graph showing relation between stress and strain 31

Figure 3.9 Molded samples are left for 7, 14 and 28 curing days 32

Figure 3.10 Sample undergo UCS test using triaxial compression

test machine 32

Figure 4.1 Particle size distribution of the soil sample 36

Figure 4.2 Graphical results of the penetration test 39

Figure 4.3 OMC chart for every admixture 43

Figure 4.4 Graph showing undrained cohesion against curing days 45

xi

LIST OF SYMBOLS AND ABREVIATION

UCS Unconfined Compression Strength

CFBC Circulating Fluidized Bed Combustion

OMC Optimum Moisture Content

MDD Maximum Dry Density

ASTM American Society for Testing and Materials

rpm Rotation Per Minute

µm Micrometer

mm Millimeter

ml Mililiter

g Gram

Rh True Reading

R’h Hydrometer Reading

Cm Meniscus Correction

PI Plasticity Index

LL Liquid Limit

PL Plastic Limit

LD Oven-Dried Sample Length

LO Initial Sample Length

qu Unconfined Strength

Cu Undrained Cohesion

kPa Kilo-Pascal

Particle Density

xii

% Percent

kN kilo-Newton

Sg Specific gravity

xiii

LIST OF APPENDICES

Appendix Title Page

A Calculation for the clay sample’s moisture content 53

B Hydrometer Test’s Data Analysis 54

C Data Analysis of Liquid Limit 57

D Data Analysis of Plastic Limit 58

E Data Analysis of Specific Gravity 59

F Data Analysis of Compaction Test (Standard Proctor Test) 61

G Data Analysis of UCS Test 63

H Graph of Stress against Strain for all samples undergo

UCS Test 130

I The value of qu and Cu for every sample 148

1

CHAPTER 1

INTRODUCTION

1.0 General

Clay is the common name for a number of fine-grained earthy materials that

become plastic when wet. As one of the principle types of soil, clay can be easily found

in the local area. It has an individual size smaller than 0.002 mm compare to other types

of soil. Clays often form colloidal suspensions when immersed in water, but the clay

particles will flocculate and settle quickly in saline water. Clay can easily molded into a

form that they retain when dry, and they become hard and lose their plasticity when

subjected to heat (Grim, 1971).

Clay plays an important role in architecture, industry and agriculture. Nowadays,

in architecture section, clay is still being used to form brick, manufacture tile for wall or

floor coverings. Other uses include pipes for drainage and sewerage. Expanded clays are

used as a lightweight aggregate in the manufacture of expanded clay blocks used for

2

insulation. However, the major use of clay, after brick manufacture, is in the

manufacture of cement.

In Sarawak, clay be easily found and generally, it can be categorized into two

classes; residual clay and transported clay. Residual clay is clay that is found in its place

of origin while transported clay is clay that was removed from its original place by agent

of erosion and then deposited to a new distant position. Residual clays are most

commonly formed by surface weathering, that includes the chemical decomposition of

rocks such as granite-containing silica and alumina; the solution of rocks, such as

limestone-containing clayey impurities, which are deposited as clay when being

insoluble; and by the disintegration and solution of shale. One of the commonest

processes of clay formation is the chemical decomposition of feldspar.

One major problem related to clay is its high compressibility because of its fine

particle size. Any foundation constructed on the clay subgrade has risk of failure when

the clay layer suddenly settled due to moisture and load.

An improvising of clay properties can be made by mixing it with fly ash as a

replacement to lightweight coarse aggregates which will be useful in the construction

practice. Fly ash is produced from coal-fired thermal power plants which are considered

as waste. In order to reduce the increasing amount of these wastes, they were reused in

3

many productions of materials and also in construction. Both possess finer particle size

and usually used as a replacement to aggregates in concrete and road sub-base.

The usage of fly ash has been done for a long time in concretes which results in

lighter concrete self-weight, while also reducing costs when producing optimum

concretes. While they were widely used as admixtures in concrete, its effect on clay is

still need to be defined. A study of the usage of both fly ash and bottom ash on clay

could also be made to investigate the changes in its properties to improve the usage of

clay in industrial and construction sector.

4

1.1 Problem Statement

The mixture of fly ash to clay soil could affect the clay in its main properties.

This is because, theoretically, the fine particle size of fly ash will fill the void between

the clay’s particles and may change the composition’s density, permeability, workability

and also its strength. From the various amount of the mixtures used, there might be at

some percentage where the clay product will possess the optimum strength.

When the proper mixture of the admixtures are determined, which gives

optimum strength to the harden clay, the mix proportion can be used in the industry as to

provide higher service level of clay product. Besides that, natural resources can also be

preserved while industrial wastes, which are fly ash and bottom ash, can be recycled

instead of being disposed to the nature.

1.2 Aim of study

Since the changes in clay properties with mixtures of fly ash and bottom ash are

still not yet well defined, there is a need to study its behavior with different mixture of

those materials through lab experiments.