Enhancing concrete properties with the use of coconut (coir) fibers and admixture

Abstract

In countries where industrialization is on the rise there is a corresponding increase in waste

production resulting from industries which eventually upsetsthe environment and community

for which they provide. While most of these waste generated are hazardous and should be

managed, others could be put to appropriate use either directly or after been recycled. Most

agro-waste can be recycled and be used asraw materialsfor manufacturing various products.

This research is designed to investigate the effectiveness of the use of coconut fibers (coir) as

a micro-reinforcement in concrete. The various mix proportions, the method of mixing,

handling and placing, and the properties of fresh and hardened natural fiber reinforced

concretes are described in this report. The properties under research include flexural and

compressive strength of the coconut fiber reinforced concrete (CRFC) at varying percentages

(0.1%, 0.3%, 0.5% by weight of cement) of fiber. The optimal percentage of fiber for both

compressive and flexural strength was determined. For each combination of proportions of

concrete two beams and three cubes were tested for their mechanical properties. By testing of

cubes and beams we found that there is an increment in the various properties and strength of

concrete by the addition of fiber as reinforcement, up to an optimum percentage where the

strength startsto drop. The Flexuralstrength wasseen to increase considerably by about 17.6%

with batch S0.3% giving the highest value (8.03N/mm2

) while the compressive strength

improved by 23% with batch S0.1% having the prime value (31.37N/mm2

).

TABLE OF CONTENTS

ABSTRACT ...........................................................................................................................I

DEDICATION .....................................................................................................................II

ACKNOWLEDGEMENTS...............................................................................................III

CERTIFICATION .............................................................................................................IV

TABLE OF CONTENTS.................................................................................................... V

List of Tables........................................................................................................................ X

List of Figures.....................................................................................................................XI

CHAPTER ONE: INTRODUCTION ................................................................................ 1

1.1 Background of Study .............................................................................................. 1

1.2 Problem Statement.................................................................................................. 2

1.3 Aim and Objectives ................................................................................................ 3

1.4 Justification of Study .............................................................................................. 3

1.5 Scope of Study ........................................................................................................ 4

1.6 Limit

VI

2.3.4 Natural Fibers ..................................................................................................... 8

2.3.4.1 Bamboo Fibers........................................................................................... 9

2.3.4.2 Jute Fibers.................................................................................................. 9

2.3.4.5 Flax and Vegetable Fibers ....................................................................... 10

2.3.4.3 Sisal Fibers............................................................................................... 10

2.3.4.4 Palm Fiber................................................................................................ 11

2.4 Influence of Natural Fibers on Concrete Properties ............................................. 11

2.4.1 Compression Strength....................................................................................... 11

2.4.2 Flexural Strength............................................................................................... 12

2.5 Coconut................................................................................................................. 13

2.5.1 Plant .................................................................................................................. 14

2.5.2 Fruit................................................................................................................... 14

2.5.3 Coconut Fibers.................................................................................................. 15

2.5.3.1 Chemical and physical Properties of coir fibers ...................................... 17

2.5.3.2 Manufacturing Process of Coconut Fiber:............................................... 18

2.5.3.2.1 Harvesting and husking of coconut: .................................................... 18

2.5.3.2.2 Retting of coconut fiber:...................................................................... 18

2.5.3.2.3 Extraction of Fiber:.............................................................................. 19

2.5.3.2 Common Application of Coconut Fiber .................................................. 19

2.5.3.3 Applications of Coir in Civil Engineering Technology ........................... 20

2.5.3.3.1 Plaster .................................................................................................. 20

2.5.3.3.2 Roofing material.................................................................................. 21

VII

2.5.3.3.3 Slabs .................................................................................................... 21

2.5.3.4 Importance of Coconut in sustainability.................................................. 21

2.6 Concrete................................................................................................................ 22

2.6.1 Constituents of Concrete...................................................................................... 23

2.6.1.1 Aggregate...................................................................................................... 23

2.6.1.2 Cement .......................................................................................................... 23

2.6.1.2.1 Types of cement ..................................................................................... 24

2.6.1.3 Water............................................................................................................. 25

2.6.1.4 Admixtures .............................................................................................. 25

2.6.1.4.1 Classification of Admixtures............................................................... 25

2.6.1.4.2 Mineral Admixtures ............................................................................ 27

2.6.1.5 Additives.................................................................................................. 28

2.6.2 Properties of Concrete ...................................................................................... 28

2.6.2.1 Workability.............................................................................................. 28

2.6.2.2 Durability................................................................................................. 28

2.6.2.3 Strength.................................................................................................... 29

CHAPTER THREE: RESEARCH METHODOLOGY................................................. 30

3.1 Materials Used ...................................................................................................... 30

3.1.1 Ordinary Portland Cement................................................................................ 30

3.1.2 Coconut Fiber (COIR) ...................................................................................... 30

3.1.3 Water................................................................................................................. 31

3.1.4 Aggregates........................................................................................................ 31

VIII

3.1.4.1 Fine Aggregate ........................................................................................ 31

3.1.4.2 Coarse Aggregate .................................................................................... 31

3.2 Characterisation of Raw Materials........................................................................ 32

3.3 Experimental Procedure........................................................................................ 32

3.4 Preparation of Specimens ..................................................................................... 33

3.4.1 Mix Design ....................................................................................................... 34

3.4.2 Batch Detailing ................................................................................................. 36

3.5 Mixing and Curing................................................................................................ 36

3.6 Test carried out on Concrete Samples .................................................................. 37

3.6.1 Test on Fresh Concrete ..................................................................................... 37

3.6.1.1 Slump Test............................................................................................... 37

3.6.2 Test on Hardened Concrete............................................................................... 38

3.6.2.1 Compressive Strength Test...................................................................... 38

3.6.2.2 Flexural Strength Test.............................................................................. 40

CHAPTER FOUR: RESULTS AND DISCUSSION ...................................................... 42

4.1 Introduction........................................................................................................... 42

4.1.1 Test on Fresh Concrete ..................................................................................... 42

4.1.2 Test on Hardened Concrete............................................................................... 43

4.1.2.1 Flexural Test ............................................................................................ 43

4.1.2.2 Compressive Strength Test...................................................................... 46

4.2 Density Determination Test ............................................................................ 49

CHAPTER FIVE: CONCLUSION AND RECOMMENDATION ............................... 51

IX

5.1 Conclusion ............................................................................................................ 51

5.2 Recommendations................................................................................................. 52

REFERENCES ................................................................................................................... 53

APPENDICES .................................................................................................................... 57