OPTIMUM FINE AND COARSE AGGREGATES PROPORTION TO PRODUCE CONCRETE STRENGTH

GOKOJOHIN

Tesis Dikemukakan Kepada Fakulti Kejuruteraan, Uiversiti Malaysia Sarawak Sebagai Memenuhi Sebahagian Daripada Syarat

Penganugerahan Sarjana Muda Kejuruteraan Dengan Kepujian (Kejuruteraan Awam)

2000

p

To my beloved father and mother.

1l

ACKNOWLEDGEMENTS

First of all, I would like to thank God for giving me the strength to finish my study

successfully. Thanks also goes to my supervisor, Haji Mohammad Ibrahim Safawi

bin Haji Zain, for the useful guidance and supervision offered to me throughout the

period of this study.

A very special thanks to my family, especially to my father, Johin Gidob, my

mother, Noip Rieh, and to my brothers and sister, for their love, patience, guidance

and inspiration.

Thanks also to all my friends, who has supported, inspired and guided me over the

past five years of my study in UNIMAS.

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ABSTRACT

Nowadays, concrete has becoming more and more important in any

construction works. There will be no progress in development without concrete.

Almost all mega projects in this country involve the using of large amount of

concrete. As demand for concrete increases, thus the price of cement (main

component in concrete production) also increases. Because of this, more money

need to be spent on concrete. Because of that, something needs to be done in order

to cut down the expenditure on this material. In this final year project, quarry chip

will be introduced as a new ingredient in making concrete. Quarry chip can be

collected for free from a quarry since it is a waste product of rock crushing. Thus,

there will be no problems arise due to shortage of this material. The project will be

mainly based on experimental works. These experimental works were done in a

laboratory where all the equipment and materials were kept. The purpose of this

study is to have a look on the influence of quarry chip on concrete strength. Beside

that, there will also test conducted on the fresh concrete such as slump test and flow

table test. From observation, it is found that concrete mixed with quarry chip is more

dry and stiff, compare to normal concrete Vvith the same design. By using different

amount of quarry chip for each batch of concrete mixed, the concrete strength

produced will vary. As the amount of quarry chip is increased, the concrete strength

will also increase. Thus, this proves that quarry chip affects concrete strength in a

good manner. The findings are really reliable, as there is no admixtures used in the

mixing. If this result is accepted by all, then it is said that a more economical way of

producing concrete with high strength has been found.

IV

ABSTRAK

Kini, konkrit menjadi semakin penting di dalam kelja-kelja pembinaan untuk

pembangunan. Hampir semua projek- projek mega eli negara ini melibatkan

penggunaan konkrit yang banyak. Apabila perrnintaan terhadap konkrit meningkat,

maka harga untuk bahan asas konkrit terutamanya simen pun turut meningkat. Oleh

itu, sesuatu perlu dilakukan untuk menurunkan perbelanjaan penghasilan konkrit.

Untuk projek tahun akhir, penggunaan butiran kuari sebagai satu bahan baru di

dalam penghasilan konkrit akan diperkenalkan. Butiran kuari merupakan serpihan

batu yang terhasil daripada proses pemecahan batu eli kuari. Ia biasanya diambil

secara percuma dari kuari. Maka, ini dapat menjamin kelancaran projek kerana tidak

akan timbul masalah kekurangan bahan tersebut. Projek ini lebih berasaskan kepada

kelja-kelja amali yang dilakukan di dalam makmal, di mana semua bahan serta radas

boleh didapati. Tujuan kajian ini adalah untuk melihat pengaruh butiran kuari

terhadap kekuatan konkrit. Selain itu, beberapa ujian ke atas konkrit basah (baru

dibancuh) akan turut dijalankan seperti ujian penurunan dan ujian aliran. Daripada

pemerhatian kami, elidapati konkrit yang menggunakan butiran kuari adalah lebih

kering serta likat. Ini adalah kerana butiran kuari menyerap banyak air. Dengan

menggunakan jumlah butiran kuari yang berlainan bagi setiap bancuhan, didapati

ada perubahan dari segi kekuatan konkrit yang terhasil. Semakin banyak butiran

kuari digunakan, semakin tinggi kekuatan konkrit yang terhasil. Seandainya

keputusan ini diterima umum, maka ini menunjukkan bahawa satu penemuan barn

telah dicapai di dalam penghasiJan konkrit yang mempunyai kekuatan yang tinggi

secara lebih ekonomi.

v

TABLE OF CONTENTS

Page

BORANG PENYERABAN TESIS UNIMAS

PERAKUAN PENYELIA

TITLE

DEDICATION II

LIST OF APPENDIX XlV

ACKNOWLEDGEMENTS III

ABSTRACT IV

ABSTRAK V

TABLE OF CONTENT VI

LIST OF FIGURES x

LIST OF TABLES XII

CHAPTER 1 INTRODUCTION 1

1. 1 Introduction 1

1.2 Objective 2

1.3 Review of Chapters 2

I

vi

CHAPTER 2 LITERATURE REVIEW 4

2.1 Concrete 4

2.1.1 Aggregates 7

2.l.2 Cement 7

2.1.3 Voids in Concrete 8

2.2 Structure of Concrete 9

2.2.1 Transition Zone 9

2.2.2 Transition Zone Strength 10

2.3 Concrete Strength 11

2.3.1 Shrinkage of Concrete 11

2.3.2 Compressive and Tensile Strength 12

2.3.2.1 Factors Affecting Strength 13

a) Water/Cement Ratio 13

b) Aggregate 14

c) Type of Cement 19

d) Curing 20

2.4 Conclusion 20

CHAPTER 3 METHODOLOGY 22

3.1 Introduction 22

3.2 Reading Materials 22

3.2.1 Sieve Analysis 23

3.2.2 Workability Test 26

I

vii

3.2.2.1 Slump Test 28

3.2.2.2 Flow Table Test 31

3.2.2.3 Compacting Factor Test 33

3.2.2.4 Vebe Test 35

3.2.3 Concrete Cube Test 36

3.3 Trial Test 40

3.4 Experimental Works 42

3.5 Conclusion 46

CHAPTER 4 RESULTS AND ANALYSIS 47

4.1 Introduction 47

4.2 Trial Test 48

4.3 Experimental Works 52

4.3.1 Control Batch 53

4.3.2 Second Batch 58

4.3.3 Third Batch 65

4.3.4 Fourth Batch 72

4.4 Fineness Modulus Analysis 76

45 Workability Analysis 77

4.6 Compressive Strength Analysis 79

4.7 Optimum Proportion 81

VUl

CHAPTER 5 CONCLUSION AND RECOMMENDATION 83

REFERENCES 85

APPENDIX 87

ix

LIST OF FIGURES

Figure Page

2.1 Process of concrete mixing 5

2.2 Concrete components by volume 6

2.3 Cross section of hardened concrete where cement 8

and water paste completely coats each aggregate

particle and fills all spaces between them

2.4 Effect of water/cement ratio and age on concrete strength 14

2.5 The influence ofcuring conditions on concrete strength 20

3.1 Sieves stacked together according to their size 26

3.2 Standard cone and funnel for slump test 28

3.3 Measuring slump 29

3.4 Types of slump 30

3.5 Typical flow table 32

3.6 Typical compacting factor apparatus 34

3.7 Typical vebe test apparatus 36

3.8 N ewl y casted concrete cubes 37

3.9 Concrete cubes under curing process 38

3.10 Cracking patterns ofconcrete cube and cylinder 39

3.11 Concrete cube ready for compression test 40

4.1 Graph of sieve analysis (sand) for trial test 50

x

~-~~~~~~~-------------------

'"

4.2 Graph of sieve analysis (quarry chip) for trial test 50

4.3 Concrete in mixer machine 54

4.4 Concrete poured into sampling tray 54

4.5 Graph of sieve analysis (sand) for control batch 58

4.6(a) Graph of sieve analysis (sand) for second batch 61

4.6(b) Graph of sieve analysis (quarry chip) for second batch 61

4.7 Slump for second batch 63

4.8 Graph of compressive strength with age for second batch 65

4.9(a) Graph of sieve analysis (sand) for third batch. 68

4.9(b) Graph of sieve analysis (quarry chip) for third batch 68

4.10 Zero slump obtained 70

4.11 Graph of compressive strength test with for third batch 71

4.12 Graph of sieve analysis (quarry chip) for fourth batch 74

4 .13( a) Graph ofworkability tests results 77

4. 13(b) Graph of results for compacting factor test 78

4.14 Compression test results 81

Xl

LIST OF TABLES

Table Page

2.1 Various shapes for aggregate 16

2.2 Typical surface textures of a selected group ofaggregates 18

2.3 Standard Portland cements 19

3.1 Sieve analysis ofa concrete fine aggregate 25

3.2 Typical slump and compacting factor values for different 30

workability degree

3.3 The mix proportion for the trial mix 41

3.4 Mix design of concrete for experimental works 44

3.5 Amount of materials for each batch 43

4.1 Sieve analysis on sand for trial test 48

4.2 Sieve analysis on quarry chip for trial test 49

4.3 Results of compressive strength test for trial test 51

4.4 Workability tests results for control batch 55

4.5 Results of compression test for control batch 56

4.6 Sieve analysis on sand for control batch 57

4.7(a) Sieve analysis on sand for second batch 59

4.7(b) Sieve analysis on quarry chip for second batch 60

4.8 Workability tests results for second batch 62

4.9 Results of compression test for second batch 64

Xll

------------------------.-..--.~,..

4.1O(a) Sieve analysis on sand for third batch 66

4.1 O(b) Sieve analysis on quarry chip for third batch 67

4.11 Workability tests results for third batch 69

4.12 Results ofcompression test for third batch 71

4.13 Sieve analysis on quarry chip for fourth batch 73

4.14 Workability tests results for fourth batch 75

4.15 Results of compression test for fourth batch 76

4.16 Values of fineness modulus for comparison 77

Xlll

87

LIST OF APPENDIX

Appendix Page

A Project planning

XIV

CHAPTER 1

INTRODUCTION

1.1 Introduction

Concrete is one of the most important construction materials other than steel.

There are many types of structures that requires concrete in order to construct it,

such as multistory building, railroad, warehouses and darns. It is very dominant in a

developing country such as our country, Malaysia. Examples of big project in

Malaysia that requires large amount of concrete are Bakun Hydroelectric Dam and

Petronas Twin Towers.

Concrete can be divided into several types, such as self-compacted concrete,

high strength concrete (HSC) and normal strength concrete (NSC). The first two

examples mentioned are under high-performance concrete (HPC). High performance

concrete is a type of concrete that has special features. It can do works that can't be

achieved by using conventional concrete. Beside that, its application can contribute

in reducing construction period as it saves time.

Normal strength concrete is the type of concrete that has 28-day compressive

strength below than the one that could be achieved by high strength concrete, which

is below 50 Mpa. Examples ofNSC are concrete of Grade 30 and Grade 40. NSC is

usually produced in a normal way without addition of admixtures such as silica

fume and superplasticizers.

In this project, a study on how to increase concrete strength is going to be

conducted by introducing quarry chip in the concrete mixture. This study is made

possible due to the availability of quarry chip, which can be collected from a nearby

quarry without any payment.

1.2 Objective

The objectives of this project are shown below:

1) To introduce quarry chip, a waste product in a quarry, as a new ingredient in

concrete preparation.

2) To study the effects of using quarry chip in concrete production on the

strength and workability of concrete. This quarry chip is combined together

with sand to produce fine aggregates.

3) To find relationship between coarse to powder ratio and strength ofconcrete.

4) To give better understanding on concrete production process, such as

selection of materials, producing mix design for concrete, tests on fresh and

hardened concrete.

1.3 Review of Chapters

In order to have a more organized way to represent the data and information

gathered throughout the study, they were divided into several chapters. Each chapter

contains different information and data. For the purpose of this study, there will be 5

chapters overalL

2

The first chapter, which is the introduction chapter, provides brief idea to the

readers on the type of study that is going to be conducted and also to explain the

objective of the project. In Chapter 2, there will be information gathered based on

the previous studies that were done by other people. This information is very useful

throughout the study, especially the one on concrete strength. Most of the content in

this chapter is based on books and journals.

The methodology of the study will be discussed more in Chapter 3. Here,

details on types of test and material used will be shown. The details will give brief

idea on how the study is conducted in order to get results. In Chapter 4, the results of

the tests conducted are shown here. The analysis for the data gathered would also be

part of this chapter. For the final chapter, which is Chapter 5, conclusions on the

achievement of the project will be featured here. This will include the

recommendations, which is important for future studies.

3

psi

CHAPTER 2

LITERATURE REVIEW

2.1 Concrete

Concrete is mainly a mixture of two main components that are aggregates

and paste. Here, aggregates consist of coarse aggregate and fine aggregate while

paste is a combination of cement and water. In concrete, paste plays a major role in

binding aggregates into rocklike mass as the paste hardens. The hardening is due to

the chemical reaction between cement and water. The process of concrete mixing is

easy to understand in the form of diagram, as shown in Figure 2.1.

The cement paste component functions in the first instance to coat and

"lubricate" the individual grains of sand, thereby imparting "workability" to the

mortar phase. In turn, the mortar serves to lubricate the coarse aggregate particles

and so give workability to the fresh concrete.

The quantities of cement paste and mortar necessary to achieve appropriate

levels of workability will depend on the amounts of sand and coarse aggregate

present in the concrete, on the associated "gradinglf of constituent particle sizes, and

on the actual level of workability required for the job. If there is insufficient mortar

or cement paste the mix will tend to be "harshHand unworkable. Conversely, too

much mortar or cement paste will promote the likelihood of Hsegregation" effects

whereby the coarser aggregate fractions tend to separate out from the remainder of

the mix.

4

Portland Cement +I I B I

."

Cement Paste + Fine Aggregate (Sand)

l I

~r

I Mortar I + I Coarse Aggregate I I

."

Concrete! I

Fig. 2.1 Process ofconcrete mixing.

Concrete does not set and harden through a physical drying-out process.

Setting and hardening is due instead to a series of chemical reactions between the

Portland cement and water present in the mix. This is due to a process called

hydration where the original cement paste phase is transformed into a sort of

"mineral glue" which acts to bind the sand and coarse aggregate fractions together.

5

In concrete, aggregates make up 60% to 75% of total volume of concrete.

About 25% to 40% of concrete volume consists of cement paste. Voids make up

about 2% to 8% of total volume. The above information can be summarized in

Figure 2.2 below.

........-+---Voids (2% - 8%) ~~----~~----~

: -: -: . :- :- :- : -: • :- :- :-.....t-.-.~.-:+--- Cement Paste (23% - 40%)

Aggregates (60% - 75%)

Fig. 2.2 Concrete components by volume.

From the total volume of cement paste above, about 25% to 40% of its

volume consists of cement while water represents about 60% to 75%. For

aggregates, about 30% to 45% of its volume are fine aggregate while coarse

aggregate represents about 55% to 70%. The above information is based on

conventional concrete.

6

F'"

2.1.1 Aggregates

Aggregates are considered as major component in concrete. It is usually

divided into two types, which are fine aggregate and coarse aggregate. Coarse

aggregate is usually defined as materials or aggregates that pass a 100 mm square

opening sieve and are retained on the NO.4 (4.75 mm) sieve. Types of aggregates

are usually gravel or crushed stone. Gravel is produced due to natural disintegration

and rock abrasion while crushed stone is the product of rocks, boulders or large

cobblestones crushed using artificial way.

Fine aggregate is the materials that pass the No.4 (4.75 mm) sieve. It is

predominantly retained on the No. 200 (75 J.1m) sieve. Sand is the most commonly

used fine aggregate in mixing concrete. Sand is the product of natural disintegration

of rock.

2.1.2 Cement

Cement is the most important material in concrete production. Without it,.

aggregates would not bind together to produce a hard mass. Portland cement is the

most widely used cement. It is also known as hydraulic cement. This means that

Portland cement will harden when it is mixed with water in a proper proportion. The

term "cement" used throughout this text refers to Portland cement unless otherwise

stated.

7

P,2k

2.1.3 Voids In Con.crete

Voids in aggregates, represent amount of air space between aggregates or

space between particles. It is generally expressed as a percent of gross volume that is

solid volume plus voids volume. For example, 40% void means 40% of aggregate

volume are filled with air while solids (aggregates) occupy the remaining 60%. This

is done by assuming that the aggregates are in a dry condition.

In concrete mixes, voids content in the mix should be low as possible. This is

because voids can decrease strength. If concrete has high content of voids, this will

cause concrete to crack easily when load is applied. When concrete is made, cement

paste will fill voids in fine aggregate, thus producing mortar. The mortar produced

win then fins the voids in coarse aggregate, thus producing concrete.

To have a good mixture of concrete, about 75% of concrete volume should

be occupied by mixed aggregates. The remaining volume should consists of cement

paste and air voids.

Fig. 2.3 Cross section of hardened concrete where cement and water paste

completely coats each aggregate particle and fills all spaces between them.

s

2.2 Structure of Concrete

Concrete structure can be divided into three phases. They are the hydrated

cement paste, transition zone and coarse aggregate. Transition zone and hydrated

cement paste are the nvo components that are influenced by environment humidity,

time and temperature. Transition zone is the weakest compare to the other two

components, as it exists as thin shell. Thus, more attention should be put on this part

in order to improve strength.

2.2.1 Transition Zone

Transition zone is a small area surrounding coarse aggregate (typically 10 to

50 J..Ull wide around the particles of coarse aggregate). In freshly compacted

concrete, it consists of water film. Then, it will form ettringite and calcium

hydroxide. For concrete with high water/cement ratio, these nvo crystalline products

consist of relatively larger crystals. The transition zone between hydrated cement

paste and coarse aggregate influence more on the behavior of concrete.

This transition zone is formed due to water content. For an ordinary concrete

mixture (without admixtures present), the water content is quite enough to cause

'bleeding', which is a form of segregation. For this situation, water in the concrete

mixture tends to move upwards, as water is the lightest component in fresh concrete

mixture. For the heavier solids, it tends to settle down. Only part of the bleed-water

reaches the concrete surface where it may be lost by eva}X)ration. Owing to the wall

effect, a large amount of bleed water gets blocked at the aggregate surfaces,

especially at the underside ofcoarse aggregate particles.

9

r 2.2.2 Transition Zone Strength

The attraction caused by van der Waals force plays a main role in the

adhesion of hydration product and the aggregate particle. Thus, the transition zone

strength depends on volume and size of voids present. The larger the size of calcium

hydroxide crystals, the less it posses adhesion capacity. This is due to lower surface

area and weak van der Waals attraction forces.

For ordinary concrete, the transition zone at early ages is very weak. It

microcracks even under the influence of stresses induced by environmental

temperature and humidity changes. The presence of microcracks contributes mainly

to its poor strength. The amount of microcracks depends on various parameters,

which are aggregate size and grading, cement content, humidity, curing condition

and also water/cement ratio.

Segregation proneness in compacting will increase as the aggregate is poorly

graded. Thus. causing thick water films to form below it. The thickness of this water

film depends on the aggregate size. The larger the size, the thicker the water film.

This will cause the transition zone to be susceptible to cracking when subjected to

the influence of tensile stresses induced by movements between the aggregate and

the hydrated cement paste which may arise from the drying or the cooling of

concrete. This means that concrete already have microcracks even before a structure

is subjected to load.

10