IMPROVEMENT OF GEOTECHNICAL PROPERTIES OF
LOCAL CLAY BY USING FLY ASH
Muhammad Wazizi Hamzar b. Abdul Aziz
Bachelor of Engineering with Honours (Civil Engineering)
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 : __________________
“ 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
“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
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
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
DEDICATION
Dedicated to my beloved family, friends and all the people that have supported, encouraged and inspired me through good and hard times.
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.
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.
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.
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 xiLIST 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
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
3.2.2.2 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
REFERENCES 50
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
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
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
% Percent
kN kilo-Newton
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
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
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
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.
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.