Faculty of Engineering

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THE EFFECT OF FIBRE CONTENT ON THE SPLIT TENSILE STRENGTH OF SAGO FIBRE REINFORCED CONCRETE

Wong Sia Siang

Bachelor of Engineering with Honours (Civil Engineering)

2017

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UNIVERSITI MALAYSIA SARAWAK

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Final Year Project Report  Masters

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Student’s Declaration:

I WONG SIA SIANG, 44649, FACULTY OF ENGINEERING hereby declare that the work entitled THE EFFECT OF FIBRE CONTENT ON THE SPLIT TENSILE STRENGTH OF SAGO FIBRE REINFORCED CONCRETE is my original work. I have not copied from any other students’ work or from any other sources except where due reference or acknowledgement is made explicitly in the text, nor has any part been written for me by another person.

____________________ _________________________

Date submitted WONG SIA SIANG (44649)

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I IR DR DELSYE TEO CHING LEE hereby certifies that the work entitled THE EFFECT OF FIBRE CONTENT ON THE SPLIT TENSILE STRENGTH OF SAGO FIBRE REINFORCED CONCRETE was prepared by the above named student, and was submitted to the “FACULTY”

as a partial fulfillment for the conferment of B.ENG. (HONS) (CIVIL), and the aforementioned work, to the best of my knowledge, is the said student’s work.

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(IR DR DELSYE TEO CHING LEE)

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THE EFFECT OF FIBRE CONTENT ON THE SPLIT TENSILE STRENGTH OF SAGO FIBRE REINFORCED CONCRETE

WONG SIA SIANG

A dissertation submitted in partial fulfillment of the requirement for the degree of Bachelor of Engineering with Honours

(Civil Engineering)

Faculty of Engineering Universiti Malaysia Sarawak

2017

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To my beloved family, friends and lecturers.

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ACKNOWLEDGEMENTS

First and foremost, I would like express my deepest gratitude to my supervisor, Ir. Dr Delsye Teo Ching Lee, for her constant support, advices, and guidance to me throughout this research and thesis writing. I would like to take this opportunity express my gratefulness to her selflessly supervision on the proper procedures for research and laboratory works. Her guidance, patience, time and understanding in reviewing my thesis writing are very much appreciated.

Secondly, I would like to extend my gratitude to my co-supervisor, Dr Lim Soh Fong, for her assistance in getting the main raw material for this research, which are the sago fibre. Apart of this, I would like to thank the assistant engineers of Civil Engineering Laboratory for their help and guidance on my experimental work and the operation of the machine.

Last but not least, I would like to express my thankfulness to my beloved family for their spiritual and financial support throughout this research and my four years’

undergraduate study. My appreciation also goes to my friends and housemates who always there to listen to me for my happiness and depression. Their love and encouragement are incentive for me to overcome all the difficulties during this period of time.

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ABSTRACT

Sago fibre is one of the major constituents found in sago pith waste after the processing of sago starch. The previous studies done by various researchers had identified that the addition of fibre in concrete could enhance the tensile strength development in concrete inherently by the bridging effect of fibre. However, there is still lack of study on sago fibre reinforced concrete. Therefore, this research is conducted to investigate the effect of fibre content towards tensile strength development in sago fibre reinforced concrete. It is vital to ensure the feasibility of application of sago fibre reinforced concrete in actual practice. In this research, the sago fibre applied is 30mm in length and the percentages of fibre added are 0.5%, 1.0%, 1.5%, and 2.0% by concrete volume respectively. The results of these fibre contents are compared with the control sample (0% fibre content) at curing ages of 3, 7, 28, and 56 days. The test for workability of fresh concrete involved slump test, while the strength properties of hardened concrete is tested by compressive and split tensile strength tests. In general, the workability of concrete decreased with the increment of sago fibre content. Besides that, the compressive strength developed in sago fibre reinforced concrete is higher than the control sample during the early ages, but declined at later ages. Meanwhile, the tensile strength of sago fibre reinforced concrete is improved for lower sago fibre content of 0.5% and 1.0%, but reduced for further increment in fibre content at 1.5% and 2.0%.

Therefore, the addition of 1.0% of sago fibre in concrete is believed to give the most enhancement in tensile properties of concrete.

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ABSTRAK

Gentian sagu merupakan salah satu juzuk utama yang terdapat dalam sisa empulur sagu selepas pemprosesan kanji sagu. Kajian-kajian yang dijalankan oleh para penyelidik sebelum ini telah mengenal pasti bahawa penambahan gentian dalam konkrit boleh meningkatkan pembangunan kekuatan tegangan dalam konkrit berdasarkan kesan penyambungan gentian. Namun begitu, penyelidikan tentang konkrit bertetulang gentian sagu masih kurang. Oleh itu, kajian ini dijalankan untuk mengkaji kesan kandungan gentian atas pembangunan kekuatan tegangan dalam konkrit bertetulang gentian sagu. Ia adalah penting untuk memastikan kemungkinan applikasi konkrit bertetulang gentian sagu dalam praktikal sebenar. Dalam kajian ini, gentian sagu yang digunakan adalah 30mm panjang dan peratusan gentian yang ditambahkan adalah 0.5%, 1.0%, 1.5%, dan 2.0% berdasarkan isi padu konkrit masing-masing. Keputusan dengan kandungan- kandungan gentian ini dibandingkan dengan sampel kawalan (0% kandungan gentian) pada usia pengawetan 3 hari, 7 hari, 28 hari, dan 56 hari. Ujian tentang kebolehkerjaan konkrit segar melibatkan ujian kemerosotan, manakala sifat-sifat kekuatan konkrit keras diuji dengan ujian mampatan dan tegangan. Secara umumnya, kebolehkerjaan konkrit menurun dengan peningkatan kandungan gentian sagu. Selain itu, kekuatan mampatan dalam konkrit bertetulang gentian sagu adalah lebih tinggi berbanding dengan sampel kawalan pada peringkat awal, tetapi merosot pada usia kemudian. Sementara itu, kekuatan tegangan konkrit bertetulang gentian sagu meningkat bagi kandungan gentian yang lebih rendah, iaitu 0.5% dan 1.0%, tetapi merosot bagi kenaikan seterusnya dalam kandungan gentian sebanyak 1.5% dan 2.0%. Dengan itu, penambahan 1.0% gentian sagu dalam konkrit dipercayai dapat memberi penambahan yang tertinggi dalam sifat tegangan konkrit.

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LIST OF TABLES

Table Page

3.1 Physical properties and chemical composition of OPC. 15

3.2 Physical properties of fine aggregate. 16

3.3 Physical properties of coarse aggregate. 17

3.4 Physical properties of sago fibres used. 19

3.5 Mix proportion, slump and compressive strength of trial mix designs. 21

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LIST OF FIGURES

Figure Page

3.1 Particle distribution graph of fine aggregate. 16 3.2 Particle distribution graph of coarse aggregate. 17

3.3 Raw sago fibres in pith form. 18

3.4 Extracted and cleaned sago fibres. 19

3.5 30mm in length of sago fibres used. 19

4.1 Slump value of different percentage of sago fibre added. 26 4.2 Comparison of average density of sago fibre reinforced concrete with

respective sago fibre content at curing age of 3, 7, 28, and 56 days. 27 4.3 Compressive strength of concrete samples at curing ages of 3, 7, 28, and 56

days. 29

4.4 Comparison of tensile strength development in concrete samples at curing ages

of 3, 7, 28, and 56 days. 30

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LIST OF SYMBOLS

C - Mass of cement (kg)

Ca - Mass of coarse aggregate (kg)

d - Cross-sectional dimension of the specimen (mm) F - Maximum load (N)

Fa - Mass of fine aggregate (kg) l - Length of the specimen (mm)

m - Mass of the saturated specimen in air (kg) Sc - Specific gravity of cement

Sca - Specific gravity of coarse aggregate Sfa - Specific gravity of fine aggregate V - Volume of the specimen (m³) W - Mass of water (kg)

ρ - Density (kg/m³)

σct - Split tensile strength (N/mm²)

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LIST OF ABBREVIATIONS

ASTM - American Society for Testing and Materials

BS - British Standard

DOE - Department of Environment OPC - Ordinary Portland Cement SSD - Saturated Surface Dried UNIMAS - Universiti Malaysia Sarawak

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CHAPTER 1

Chapter 1 INTRODUCTION

INTRODUCTION

1.1 General

Concrete is a man-made product that is widely used in construction. Concrete is produced from the mixture of cementitious materials, water, and aggregates under required proportion (Gambhir, 2004). The mixture is molded into the desired size and shape, and allowed to cure and harden to form hardened concrete (Somayaji, 2001).

Gambhir (2004) stated that the hardening of concrete is due to the hydration process between water and cement and it develops strength continuously with age. However, the hardened concrete experiences high compression strength but comparatively low tensile strength, which is only about 8% to 12% of its compression strength (Setareh & Darvas, 2007). According to Gambhir (2004), plain concrete is known as the concrete without any reinforcement. Therefore, plain concrete is brittle and tends to the formation of microcracks due to its poor tensile strength.

Meanwhile, the use of conventional reinforced steel bars and restraining techniques can only provide tensile strength to the concrete members, but not the inherent tensile strength of concrete itself (Shetty, 2005). In this case, studies have been carried out by various researchers (Rai & Joshi, 2014; Merta & Tschegg, 2013; Dhandhania & Sawant, 2014; Yan et al., 2016; Ahsana Fathima & Varghese, 2014; Marar et al., 2016; Ankaiah

& Reddy, 2015, Ali, 2012; Elsaid et al., 2011; Ali et al., 2012) to study on the potential fibre materials either synthetic fibres or natural fibres to be dispersed and distributed randomly into the plain concrete to improve the strength characteristic of the concrete.

The addition of fibre has improved the mechanical properties of the plain concrete by bridging effect of fibre (Branston et al., 2016) which result from the excellent flexural- tensile strength in fibre (Rai & Joshi, 2014). According to Merta and Tschegg (2013), the benefits of low environmental impact, low cost and wide availability resources in

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agricultural fields of natural fibres have gain their popularities compared to synthetic fibres.

1.2 Research Background

According to Tay et al. (2016c), Sarawak state has the greatest production of sago plant in Malaysia and is the largest exporter for the sago starch in global. The world’s first large scale commercial plantation of sago is developed by the Sarawak land development near Mukah with an area of 7700 ha (Awang Adeni et al., 2010). In year 2007, there was about 44700 tons of sago starch been exported from Sarawak (Awang Adeni et al., 2010). The exportation of the sago starch is estimated approximately 47900 tons by the year 2013 (Department of Agriculture Sarawak, 2016).

Meanwhile, the sago pith waste has increases due to the high demand for sago starch annually. Bujang et al. (1996) mentioned that there were about 7 tons of sago pith waste been produced daily from a single sago starch processing mill (as cited in Awang Adeni et al., 2010). However, the lack of systematic disposal methods for the sago waste would result in negative impact to the environment (Tay et al., 2016a).

Tay et al. (2016b) mentioned that application of sago waste as partial substitution of raw materials in different industrial fields can minimize the amount of residues. Fujii et al. (1985) reported that the major composition of dried sago pith is about 81.51-84.72%

of starch and 3.20-4.20% of fibre components (as cited in Sunarti et al., 2012). The experimental study by Sunarti et al. (2012) also showed a similar result of 73% of starch while 7.84% crude fibre in sago pith.

The research work on the possibility of natural fibres for the development of high performance engineering products has been carried out and still continuing with the purpose of reduction in production cost and environmental destruction issues (Ramesh, 2016). Although the strength properties of concrete can be improved by natural fibres, however it may differ among types of natural fibre as each of them has their own characteristic. Hence, this research is carried out to identify the performance of strength development in sago fibre reinforced concrete under different fibre content.

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1.3 Problem Statement

The hardened concrete is good in compression strength but poor in its tensile strength.

Shetty (2015) stated that the use of conventional reinforce steel bars and restraining techniques can only improve the concrete members’ tensile strength, but not the inherent tensile strength of concrete itself. On the other hand, the agro waste from sago starch processing industries in Sarawak are abundant and readily available (Awang Adeni et al., 2010). Improper disposal of the sago waste will cause serious environmental problem.

Therefore, in order to reduce the cost of production and minimize the environmental pollution, the research work on the use of natural fibres for high performance engineering products has been carried out and still ongoing (Ramesh, 2016). However, there is lack of significant study on the use of sago reinforced concrete that has been carried out.

Therefore, the strength development of concrete towards different amounts of fibre added needs to be further investigated in order to ensure the feasibility of application of sago fibre reinforced concrete in actual practice.

1.4 Research Significance

The high demand of sago starch in overseas market has concurrently result in high production of sago waste from the sago processing mills in Malaysia, especially Sarawak.

If there is improper utilization of the sago waste, it will potentially lead to environment pollution due to its slow degradability (Aziz, 2002). Bujang and Ahmad (2000) estimated that at least 12 tons of sago starch production in a medium sized sago mill in Sarawak everyday (as cited in Bujang, 2014). According to Bujang (2014), an average of 600 logs processed in the mill would generate approximately 240 tons of waste product which contain 9.6 tons of solid waste with the major content of sago fibre. Meanwhile, the previous research studies showing that natural fibres have the potential in improving the concrete strength and durability. However, there is lack of study on the use of sago fiber as cementitious material in construction field. Therefore, this research is vital to introduce sago fibre in concrete mixing and investigate the effect of fibre content in the split tensile strength development in sago fibre reinforced concrete.

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1.5 Research Objectives

The main aim of the study is to investigate the effect of the addition of fibre amount on the tensile properties of sago fibre reinforced concrete. In order to achieve the aim of the study, the objectives are set as below:

i. To obtain a suitable mix proportion for the plain concrete as control sample with target strength of 30MPa and slump of 80 – 180mm.

ii. To study the effects of different fibre content in concrete towards the compressive strength development of sago fibre reinforced concrete.

iii. To study the effects of different fibre content in concrete towards the split tensile strength development of sago fibre reinforced concrete.

1.6 Scope of Work

In the study, sago fibre which is extracted from the sago pitch is the raw material used to analyze the effect on the concrete strength. A mix proportion of control sample with targeted strength of 30 MPa and slump of 80 – 180 mm is determined by absolute volume method. With the control mix proportion, various volume fraction of sago fibre are added in the concrete (0.5 %, 1.0 %, 1.5 %, and 2.0 %). The length of the sago fibre used in the mix is limited to 30 mm. Slump test is the only test involved for the fresh concrete. After casting, all the samples are cured with potable water in water tank under room temperature. There are two tests involved in the strength analysis of the hardened concrete, which are compressive strength test and split tensile strength test. The strength development of the hardened concrete is determined at the ages of 3, 7, 28, and 56 days respectively.

1.7 Thesis Organization

Chapter 1 of the thesis introduces briefly on the content of the thesis. It contains the research background, research significance, problem statement, research objectives, and scope of work.

Chapter 2 of the thesis explains on the literature review. This chapter included the reviews of the properties of different types of fibre reinforced concrete. There are also

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study on the previous researches on the effect of the fibre content in the split tensile strength analysis.

Chapter 3 of the thesis describes the materials used and methodology involved in this research. The types of materials used for the entire research are identified and their respective properties are determined. In addition, the required methods to conduct the tests in this research are also discussed in this chapter.

Chapter 4 of the thesis focused on the results and discussion based on the laboratory testing. The results obtained are present in the tables, graphs and figures. There are also comparisons between samples and discussion on their properties towards the changes in fibre content.

Chapter 5 of the thesis presents the conclusion and recommendation of this research.

The summary of the thesis is emphasized in the conclusion and recommendations for future research are also determined.

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CHAPTER 2

Chapter 2 LITERATURE REVIEW

LITERATURE REVIEW

2.1 General

Concrete which are made up of cement, water, fine aggregate and coarse aggregate experiences low tensile strength, weak ductility and low crack resistance. The use of conventional reinforced steel bars can only improve the tensile strength of concrete members but not the concrete itself inherently. In plain concrete, the occurrence of micro cracks in concrete before been loaded is due to drying shrinkage and other causes of volume change. These micro cracks tend to be spread out when loaded and thus result in inelastic deformation in concrete. Meanwhile, the addition of fibres which are distributed and dispersed randomly in concrete during mixing will reduce the micro cracks and improve the concrete properties significantly. This type of concrete is known as fibre reinforced concrete and it is practically applicable in construction field.

2.2 Fibre Reinforced Concrete

Fibre reinforced concrete can be defined as cement based composite material that consist of randomly distributed small fibres (Shetty, 2005). The use of fibre reinforced concrete is increased due to its improvement in static and dynamic tensile strength and also fatigue strength. However, the properties of fibre reinforced concrete are reliant on the mechanical properties, bonding properties and matrix of fibre, in addition to the quantity and distribution within the fibre matrix (Kumar, & Sangeeta, 2015). Generally, the types of fibre reinforced concrete can be divided into two categories, which are synthetic fibre reinforced concrete and natural fibre reinforced concrete based on the types of fibre used. Synthetic fibre is the man-made fibre which include steel fibre, glass

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fibre, and polypropylene fibre. Meanwhile, natural fibre is the fibre produced by plants and animals such as coir fibre, kenaf fibre, and sisal fibre.

2.2.1 General Characteristics of Fibre Reinforced Concrete

In general, fibre reinforced concrete with the content of discontinuous discrete fibres has pose a tougher and more durable concrete through integrating of three dimensional reinforcements within the concrete. Nawy (2001) stated that the addition of fibres has minimize the development or propagation of the microcracks in plain concrete, thus improve the mechanical properties of the concrete. Due to the random distribution of discontinuous fibres in the matrix in both tensile and compressive zone of concrete, the toughness and crack control performance of the concrete is enhanced through the reduction in the propagation of microcracks while the ductility is improved due to the energy absorption capacity in fibres (Nawy, 2001).

2.2.2 Factors Affecting Properties of Fibre Reinforced Concrete

Although fibre reinforced concrete could enhance in the toughness and durability of concrete itself, however, the properties of fibre reinforced concrete depends upon the type of fibre, fibre contents, orientation and distribution of fibre, and aspect ratio of fibre used (Gambhir, 2004; Shetty, 2005).

2.2.2.1 Type of Fibre

Generally, the fibre applied in concrete can be divided into two categories, namely synthetic fibre and natural fibre. Although researches had been done with both types of fibre, however, not all of them can be applied effectively and economically (Shetty, 2005). This happens due to the self-characteristics of fibre used especially its self- strength characteristics (Ali, 2012; Gambhir, 2004). Higher strength characteristics in fibre itself could enhance the strength of concrete independently (Gambhir, 2004).

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2.2.2.2 Fibre Contents

Shetty (2005) stated that quantity of fibre used could affect in the strength development in concrete. Generally, the tensile strength and toughness of concrete increase with respect to the increment in fibre content (Shetty, 2005). However, Shetty (2005) mentioned the use of higher fibre content may cause segregation and harshness of concrete and mortar. Meanwhile, Nawy (2001) explained that fibre content in excess of 2% of volume fraction could affect the uniformity of the concrete mixture.

2.2.2.3 Orientation and Distribution of Fibre

The effect of orientation and distribution of fibre is depending on the loading condition (Gambhir, 2004). According to Shetty (2005), fibre with orientation that aligned parallel to the load applied could exhibit higher tensile strength and toughness as compare to the randomly distributed or perpendicular fibre.

2.2.2.4 Aspect Ratio of Fibre

Shetty (2005) stated that the properties and characteristic of fibre reinforced concrete can be affected by the aspect ratio of fibre. Nawy (2001) defined aspect ratio as the ratio of fibre length to the diameter of fibre. Typical aspect ratio of fibre is in the ranges of 30 to 150 (Shetty, 2005). Shetty (2005) reported that increase in aspect ratio could result in higher ultimate strength in concrete. However, the relative strength and toughness is reduced with the aspect ratio more than 75 (Shetty, 2005).

2.2.3 Synthetic Fibre Reinforced Concrete 2.2.3.1 Steel Fibre Reinforced Concrete

Arunakanthi and Kumar (2016), Marar et al. (2016), and Sukumar and John (2014) had done their research on steel fibre reinforced concrete. In the research by Arunakanthi and Kumar (2016), Hook tain steel fibre with the aspect ratios of 50, 60 and 67 were used with respective length of 35mm, 30mm, and 20mm and diameter of 0.7mm, 0.5mm, and 0.4mm. Meanwhile, 0.5%, 1%, 2%, and 3% of steel fibre were added in M20 grade concrete with the mix proportions of 1:1.96:2.63 and water cement ratio of 0.45. Based

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THE EFFECT OF FIBRE CONTENT ON THE SPLIT TENSILE STRENGTH OF SAGO FIBRE REINFORCED CONCRETE