To Enhance the Properties of Concrete Mixed with Chopped Coir Fibers

GRD Journals- Global Research and Development Journal for Engineering | Volume 5 | Issue 7 | June 2020 ISSN- 2455-5703

To Enhance the Properties of Concrete Mixed with Chopped Coir Fibers Neeraj Kumar Sharma Research Scholar

S. Gurbachan Singh Professor Department of Civil Engineering Institute of Engineering and Computer Sciences, Jammu

Abstract The mechanical properties of concrete can be enhanced by using coir fibers .Fibers have the property to enhance the toughness of concrete. In this research work the compressive strength test, split tensile strength test, flexural strength test were performed. The ratio of the coir fibers in concrete is varied from 0% to 7%. The test result shows that the strength increases from 20% to 30 % in comparison with concrete without fibers. The coir fibers are obtainable in abundance, which makes it quite variable as reinforcing materials in concrete. The research work shows that the result of the compression test indicates that the present of (coconut fibers) fibers tends to reduce the compressive strength at higher fibers contents there is improvement in ductility after cracking of concrete.

Similarly flexural strength of coir fibers (CFRC) reinforced concrete is directly proportional to coir fibers content and inversely proportional to the water cement ratio. Also split tensile strength characteristics increases up to a certain percentage beyond which strength characteristics decreases. The research work shows that concrete mixed with coir fibers can be used in sewers, slabs, pavements and many more construction site as reinforcing materials.

Keywords- Coir Fibers, Toughness, Compression and Tensile Strengths, Flexural Strength, Apparent Specific Gravity

I. INTRODUCTION Concrete is most widely used construction materials all over the world. With the advancement in science and technology the large scale use of concrete is taking place with new innovations and techniques. Since the concrete is weak in tension and flexure, mostly it is reinforced with steel bars. However the usage of steel reinforcement is expensive which is not affordable for all types of works.

So, considerable efforts have been made worldwide to add various types of natural fibers to concrete.

The natural fibers such as coir fibers, jute fibers, rice husk, bamboo fibers, saw dust etc and many more fibers have certain physical and mechanical characteristics that can be utilized effectively in the development of fibers reinforced concrete (FRC).

Fibers have the property to control cracking more effectively due to their tendency to be more closely spaced than conventional reinforcing steel bars. Coir fibers are one of the most popular types of fibers used as concrete reinforcement. Such type of fibers being the most ductile among the all types of natural fibers has the potential to be used as reinforcing materials in concrete.

The concrete containing cement, water, fine aggregates (sand), course aggregates and discontinuous coir fibers are called fibers reinforced concrete. Coir fibers (CFRC) reinforced concrete is composite material having fibers as the additional ingredients, dispersed uniformly at random in small percentage by weight in plain cement concrete (P.C.C). Fibers reinforced concrete products are manufactured by adding coir fibers to the ingredients of concrete in the mixture and by transferring the green concrete into mould; the product is then compacted and curing is carried out by conventional method.

Fig. 1: Chopped Coir Fibers

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To Enhance the Properties of Concrete Mixed with Chopped Coir Fibers (GRDJE/ Volume 5 / Issue 7 / 002)

II. LITERATURE REVIEW 1) According to Domke P.V. from Nagpur has investigated the use of natural and agricultural waste products such as coconut fibers, jute fibers and rice husk ash to enhance the properties of concrete. The study also emphasizes on the fact that coconut fibers and rice husk ash not only improves the properties of concrete but it also leads to proper disposal of these waste materials and reduces their impact on environment .Thus the fiber reinforced concrete becomes environmental friendly.

2) According to Paramasivam,et.al.(1984) conducted a feasibility study of making coir fiber reinforced corrugated slabs for use in low cost housing particularly for developing countries. They give recommendations for the production of coconut fiber reinforced slabs along with cast technique. Test for flexural strength, thermal and acoustic properties were performed. For producing required slabs having a flexural strength of 22MPa, a volume fraction of 3%,a fiber length of 2.5cm and a casting pressure of 0.15MPa(1.5atmosphere) were recommended. The thermal conductivity and sound absorption coefficient for low frequency were comparable with those of locally available asbestos boards.

3) Huang gu (2009) have investigated tensile behavior of the coir fibers and related composites after sodium hydroxide treatment.

Brown coir fibers were treated by sodium hydroxide solution with concentrations from 2% to 10% separately. In the case of sodium hydroxide density with 10%, lower tensile strength of the composite was noticed compared to the cases of 2%, 4%, 6% and 8%.They concluded after alkali treatment the elongation at break point of the composite.

4) Cheul gu (2009) has compared physical, mechanical and thermal properties of manufactured coconut coir cement boards to the normal boards. Coconut coir has additional property of being light in weight with low thermal conductivity. The coconut coir-based light weight cement board could be used as insulating building material for energy conservation in buildings.

III. METHODOLOGY AND MATERIALS A. Methodology Coir fibers are extracted from the outer shell of a coconut. There are two types of coconut fibers, Brown fibers extracted from matured coconuts and white fibers extracted from immature coconuts. Brown fibers are thick, strong and have high abrasion resistance .White fibers are smoother and finer, but also weak. The methodology used in this research work is as follows:1) The coir fibers were soaked in a 7% sodium hydroxide solution.

2) The initial weight of fabric pieces was noted.

3) The fibers were kept immersed in the alkali solution for 2, 3, 5 and 8 hours 4) The fibers were then washed several times with fresh water to remove any sodium hydroxide sticking to the fiber surface.

5) Then the fibers were dried at room temperature for 48 hours followed by oven drying at 100oC for three hours.

6) The fibers are then weighted but there is no significant change in weight of the fibers.

The main objective behind the treating and washing of coir fibers is that the fibers should not contain any sticky or unwanted materials which retard the process of binding when fibers are mixed with concrete to determine the strength.

1) Compressive Strength Test Cement is a binding material .It is main constituent of concrete which decide its strength during its age. It is the resistance to crushing .It is measured in N/mm2.The compressive strength of concrete depend upon the type of cement used ,size and shape of aggregates, water-cement ratio, degree of compaction and curing.

Concrete is very strong in compression and for structural design purposes, one has to know the compressive strength by testing hardened concrete specimens. For the research work M-25(1:1:2/cement: sand: aggregates) mix is used.

B. Procedure 1) Take the cube moulds for mix (M25/1:1:2) 2) Fibers are added to (P.C.C) plane cement concrete(0%, 1%,2%,3%,4%5%, 6%,7%) by weight of the cement in each concrete mix and fiber length of 5cm is investigated .Cleaned the inside of the mould and the joints are perfectly tight.

3) Pour properly mixed samples for the given mix to the Cube mould. (150Ă—150Ă—150mm) 4) Compaction was done by placing concrete in three layers each layer is compacted with the help of standard tamping rod by means of 25 blows.

5) Level the concrete at the top of the mould by means of trowel and gave proper identification mark to the specimens.

6) Keep the cubes in laboratory for 24 hours. After 24 hours, dismantle the plates of cube moulds and take out the hardened concrete cubes carefully.

7) Immerse the concrete cubes in curing tank filled with water.

8) Tested the cubes after 3,7,28 days of curing for finding compressive strength.

9) The results is tabulated in table 4

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To Enhance the Properties of Concrete Mixed with Chopped Coir Fibers (GRDJE/ Volume 5 / Issue 7 / 002)

Fig. 2: Compressive Strength Test

2) Split Tensile Test The same procedure is adopted for sample preparation as in earlier test.

1) The concrete cubes (150x150x150mm) are removed from the curing tank and wiped off effectively. So that concrete cubes becomes fully dry. Concrete cubes are tested one by one.

2) The projecting fins are removed from the surface so that they may not come in contact with packing strips.

3) Centre lines are drawn on the two opposite faces of the cube and device; that will ensure they are in the same plane.

4) Weight of the specimen shall be noted before testing .The specimen are laid in the same plane of the pre-marked lines and the measurements of length to the nearest of 0.2 mm.

5) Then the specimen is placed in the testing machine.

6) The specimens are placed in the centering jig one by one with packing strips carefully. Now positioning along the top and bottom of the plane of the loading of the concrete cube specimen .The jig shall be placed in the machine. So, that the specimen is placed centrally .The load shall be placed on the mould face in such a way that the flexural plane will cross the trowel surface. The ratio of loading is applied without shocks and increased within range of 1.2N/mm2/min - 2.4N/mm2/min till failure.

7) Result is tabulated in table 5

Fig. 3: Split Tensile Strength Test

3) Flexural Test It tests the ability of unreinforced concrete beam or slab to withstand failure in bending.

The flexural test on concrete was conducted using center point load test method (ASTM-293) It is required for the following purposes: – Testing concrete for slabs and pavement construction. – Essentially required for concrete mix design for compliance with standards.

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To Enhance the Properties of Concrete Mixed with Chopped Coir Fibers (GRDJE/ Volume 5 / Issue 7 / 002)

Apparatus required:-Mould (15x15x75) cm, tamping rod/vibrator and testing machine.

Sample Preparation:-The same procedure is adopted as was observed in earlier tests.

C. Procedure 1) The test is conducted on universal testing machine (UTM) and the beam specimens (15x15x75) are taken out from the curing tank.

2) Place the specimen on loading point, and the finished surface of the specimen should not be in contact with loading point.

3) Centered the loading system in relation to applied loads.

4) Brought the block by applying force in contact with the specimen at the loading points.

5) Apply the load on the specimen without shocks till the point of failure at constant rate according to British standard.

6) Result is tabulated in table 3 Calculation of measurement Since the rupture is at a distance is greater than 20cm.The flexural strength is:F.S = PLeff/BD2

Fig. 4: Flexural Strength Test

D. Materials used Table 1: Fine aggregates Description Water absorption by fine aggregates is 3.32% The specific gravity of fine aggregates (sand) is 2.45 The app. specific gravity of fine aggregates is 2.69 The size of sand is 1.18 mm The bulking of fine aggregates is 12.28% It is obtained from the quarry bed Table 2: Cement Properties Description Consistency The consistency of cement is about 33%.

Fineness The fineness of cement used is 0.023 microns Initial and final setting time The initial and final setting time of cement used is 35min and 11hours respectively.

Color Cement should be greenish grey in Color.

Source A.C.C cement of 43 grade Table 3: Coir fibers Properties Description Water absorption by coir fibers is water absorption 105% specific gravity The specific gravity of fine aggregates (sand) is 0.89 Length The length of the fiber is 45mm Diameter The diameter of the fiber is .50mm Aspect ratio The average aspect of the fiber is105 Appearance Brown as thin wires Source From the open market Deformation Uneven at both sides Properties water absorption specific gravity App.Specific gravity Size Bulking of sand Source

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To Enhance the Properties of Concrete Mixed with Chopped Coir Fibers (GRDJE/ Volume 5 / Issue 7 / 002)

Course aggregates Water:-The water used in concreting operation is portable water (ph-7)

IV. RESULTS AND DISCUSSIONS Table 4: Observation table for compressive strength of concrete cube specimens Coir fibers Strength after 7 days (N/mm2) Strength after 28days (N/mm2) 0% 1% 2% 3% 4% 5% 6% 7%

11.60 11.75 11.90 12.05 12.40 13.00 15.40 14.90

22.75 24.00 24.93 25.82 26.54 27.10 27.62 26.30

Fig. 5: Compressive Strength Table 5: Observation table for split tensile strength of concrete cube specimens Coir fibers Strength after 7 days (N/mm2) Strength after 28days (N/mm2) 0% 1% 2% 3% 4% 5% 6% 7%

1.35 1.38 1.42 1.61 1.69.

1.50 1.42 1.40

2.85 2.93 3.18 3.29 3.44 3.40 3.26 3.23

Fig. 6: Split Tensile Strength

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To Enhance the Properties of Concrete Mixed with Chopped Coir Fibers (GRDJE/ Volume 5 / Issue 7 / 002)

Table 6: Observation table for flexural strength of Concrete beam specimens Coir fibers Strength after 7 days (N/mm2) Strength after 28days (N/mm2) 0% 1% 2% 3% 4% 5% 6% 7%

1.32 1.37 1.41 1.47 1.52 1.58 1.51 1.45

2.76 2.89 2.93 2.98 3.21 3.36 3.27 3.10

Fig. 7: Flexural Strength

V. CONCLUSION 1) As the coir fibers are agricultural waste which is freely available; by using coir fibers as reinforcing materials in the concrete it reduces the environmental pollution.

2) The compressive strength of the coir fiber reinforced concrete has been tested experimentally and it is clearly noted that by adding fibers up to 6% the compressive strength increases but beyond 6% the strength decreases.

3) The split tensile strength and flexural strength of coir fibers reinforced concrete increases with the increase in fiber contents but slowly and gradually up to 4% and 5% respectively as compared to conventional concrete beyond this value the reduction in strengths is observed.

4) There should be optimum percentage of fiber to be used in the concrete which can give the maximum improvement in the mechanical properties of fibers reinforced Concrete.

VI. FUTURE SCOPE 1) Admixtures can be used to reduce the number of voids which are formed due to the present of fibers in the concrete .It may also help in improving the strength characteristics of concrete.

2) The effect of coir fibers on the high strength concrete should be studied experimentally and thus use of coir fibers reinforced concrete (CFRC) can be encouraged to industrial and commercial buildings.

3) The acoustic properties of concrete reinforced with other natural fibers (such as jute fibers, saw dust, rice husk etc) have been studied and the results are fair enough to justify the use of coir fibers as alternative which is good absorbent due to the present of surface pores.

4) As we know steel reinforcement is a costly materials used in reinforced cement concrete (R.C.C) structures. Coir fibers (byproduct) act as fiber reinforcement to reduce the quantity of steel in RCC structures.

5) Coir fibers are good insulator in itself and as such it can improve the thermal properties of concrete. This is particularly useful in tropical countries where the mercury levels are quite high for most part of the years. So as to maintain the room temperature within comfort levels of its inhabitants. It can also reduce the load on air conditioning systems thus reducing the power consumption.

6) By adding coir fibers in concrete it is observed that compressive strength, split tensile strength, flexural strength increases 21%, 20%, 18% respectively after 28 days of curing.

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To Enhance the Properties of Concrete Mixed with Chopped Coir Fibers (GRDJE/ Volume 5 / Issue 7 / 002)

REFERENCES [1] [2] [3] [4] [5] [6] [7]

Ali Majid, Anthony Lin, “Mechanical and dynamic properties of fiber reinforced Concrete” Construction and building materials “.Reed Business information, Inc.(US). 2012 Noor Md. Sadiqul Hassan, Habibur Rahman Sobuz (2012),”use of coconut fiber in production of structural light weight concrete “, journal of applied sciences 12(9)831-839,2012 Vijay, A.A Parikh (2013),”An application review of coir fiber reinforced concrete”Vol.2 Issue 4ISSN:2278-7844 Bhownick B.B. and Debnath C.R.(2007),”properties of coir”, Indian coconut journal,15,(5),2007.p.12 Kshitija Nadgouda, ”Coconut fiber reinforced concrete “International journal of mechanical and production Engineering, January 2015, vol. 3(1),pages 2628,January 2015 Domke P.V.,” Improvement in the strength of concrete by using industrial and agricultural waste “.IOSR journal of Engineering, vol.2 (4), pages 755-759.

April 2012 Paramasivam P, Nathan G.K., Das Gupta N.C.” coconut fiber reinforced corrugated slabs”, International journal of cement composites and lightweight concrete, Volume 6, Issue 1, pp 19-27.1984

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