Conventional concrete is robust in compression and weak in tension in order to swamp the weakness natural fibre is being equipped. The adoption of inherent fibres as edifice constituents is boon to procure a livable production. The comprehensive mission of this exploration is to stake out the discernible inspection of natural fibre in concrete structure. The coir fibre freshly tempted an influence as a workable fibre composite material, due to certain precise mechanical property which can be compared to artificial fibre. The coir fibre is treated using natural fluid before using in concrete, so that it is not be affected by moisture content presented in concrete. In this tentative study coir fibre is extant consumed in concrete thereby, the mechanical properties such as compressive strength, split-tensile strength, and modulus of rupture of M30Grade concrete and by capricious the spoonful of fibre gratified from0%, 2% 4%,6% and 8%. Stimulation should be given for the appliance of natural fibres which are regionally procurable materials, in the domain of civil engineering.
2. Experimental Study on Behavior of Coir Fibre Reinforced Concrete
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1. INTRODUCTION
Fibre reinforced concrete (FRC) is concrete is which is used to increase its structural integrity.it is a
composite material of cement concrete or mortar and discontinuous discrete and uniformly dispersed
fibre. Natural fibre is one of the most commonly used fibres. Generally round fibres are used. The
diameter range is from 0.25 to 0.75mm. When it gets rusted and loses its strength. It has high modulus
of elasticity.
Coconut fibre is extracted from the outer shell of the coconut. There are two type of coconut fibre
brown fibre extracted from matured coconut and white fibre from immature coconut. The coir fibre is
relatively waterproof, and is one of the few natural fibres resistant to damage by saltwater. The coir
fibre is elastic enough to twist without breaking and it holds a curl as though permanently waved. Coir
the fibrous material found between the hard, internal shell and the outer coat of a coconut.[1,2].
1.1. Coconut Husk Fibre
Coconut fibre is extracted from the outer shell of the coconut.
Common name - coir
Scientific name - cocosnucifera
Plant name - arecaceae (palm) coconut
There are two type of coconut fibre brown fibre extracted from matured coconut and white fibre
from immature coconut. Brown fibres are thick, strong and high ductile strength but white fibre are
smoother and finer but also weaker [3, 4]. So in engineering brown fibre are mostly used.
Coir is the fibrous material found between the hard, internal and outer coat of a coconut
The Single fibre cells are narrow and hollow, with thick walls made of cellulose. They are pale when
immature, but later become hardened and yellowed as a layer of lignin is deposited on their walls
The coir fibre is relatively waterproof, and is one of the few natural fibres resistant to damage by
saltwater, Erosion control, 1cm diameter coconut husk fibre having a tensile strength of 7.8 MPa.
The coir fibre is elastic enough to twist without breaking and it holds a curl as though permanently
waved.
coir has high in sodium and potassium, it is treated before use as a growth medium for plants or fungi
by soaking in a calcium buffering solution; most coir sold for growing purposes is pre-treated.
1.1.1. Preparation of coir fibre
Coconut husk fibre is immersed in water for 30min.
After taking the fibre from the water it is straightened manually.
Dry the coir fibre in open space where 70-80% of moisture were removed and cut the fibre in to 6 cm.
2. EXPERIMENTAL STUDIES
2.1. Physical Properties of Concrete
The physical properties of concrete the values of the fineness modulus of the aggregate are done by
the sieve analysis apparatus. [7, 8& 9] The Specific gravity of the sand and the coarse aggregate was
done by the Pyconometer; the values are shown in the Table.1
3. S. Sastha Arumuga Pandi, S. Yamini Roja, G. Jenitha and K. Alagusankareswari
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Table 1 Physical Properties of Concrete.
Physical Properties Values
Fineness Modulus Of The Given Fine Aggregate 5.638
Fineness Modulus Of Given Coarse Aggregate 6.775
Specific Gravity Of The Given Sand Sample 2.68
Specific Gravity Of Given Coarse Aggregate Sample 2.69
Water Absorption Percentage 1.11
2.2. Slump Test on Concrete
To determine the slump values of cement concrete with different water cement ratios and draw a graph
between slump and water cement ratio. It is the fall in vertical height of a freshly laid concrete with
respect to the standard slump cone height. The slump is 0 mm for water cement ratio of 0.40.The
slump is 25 mm for water cement ratio of 0.45.The slump is 55 mm for water cement ratio of 0.5, the
values are shown in the table 2.
Table 2 Slump value verses water cement ratio
S.No Water Cement Ratio Slump in mm
1 0.40 0
2 0.45 25
3 0.50 55
2.2. Casting of Concrete
Preparation of concrete is to assemble the moulds and apply a light coat of oil to the inner faces.
Compute the quantities of materials required for casting .Weight out the individual quantity of cement,
sand and aggregate for the given concrete ratio. Spread the weighed quantity of sand on a non-
absorbent level surface, add the cement and mix them thoroughly. Spread the coarse aggregate and
sand cement mixture and turn them by a trowel or shovel to obtain a uniform mix. Add the quantity of
water and mix till a mass of uniform colour and consistency is obtained[10].Now fill the moulds in
four layers of concrete, each layer is compacted not less than 35 stokes by tamping rods. Level the top
surface of mould with trowel. After 24 hours, remove the moulded specimen from the mould. The
specimens from the moulds are immediately submerged in clean water for curing. (7 days,14 days and
28 days)
2.3. Mix Proportion of Concrete
2.3.1. Target mean strength
Ft = fck+ KS (table 8 IS 45:2000[6]) = 30+1.65 x = 38.25 N/mm2
2.3.2. Selection of Water Cement Ratio
Maximum water cement ratio =0.50 (for moderate). Based on grade of concrete, water cement ratio
take as 0.45 (table 5 IS456-2000) and also conforming (IS 10262 -1982) 0.45 < 0.50, Hence ok.
2.3.3. Calculation of Water Content
Water content =186 litre (from table 4 IS 10262-1982)
So the estimated water content = 186 litre.
4. Experimental Study on Behavior of Coir Fibre Reinforced Concrete
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2.3.4. Determination of Cement Content
Water cement ratio = 0.45
Cement content = 186/ 0.45 = 413 kg/m3
Minimum cement content =300 kg/m3
, (IS 456-2000)
413 < 300, Hence ok
2.3.5. Proportion of Volume of Coarse and Fine Aggregate
Volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate
ZoneI with water cement ratio 0.45.
Value of coarse aggregate = 0.65
Value of fine aggregate = 0.35 (table 4 IS10262-1982)
2.3.6. Mix Calculation
The mix calculation per unit volume of concrete shall be as follows,
Volume of concrete =1m3
Volume of cement = Mass of cement / (Specific gravity of Cement x1000)
= 413/(3.15x1000) =0.131m3
Volume of water = 186/(1x1000) = 0.186m3
Volume of aggregates = 1-(volume of cement +volume of water)
= 1-(0.131+0.186) = 0.682m3
Volume of fine aggregate =0.682x0.35x2.68x10 = 600 kg/m3
Volume of coarse aggregate = Volume of aggregate x0.65xsp.gtyx1000
= 0.682x0.65x2.69x1000 = 1190 kg/m3
Table 3 Mixing Proportioning of Concrete
S.No Cement
Fine
Aggregate
Coarse
Aggregate
Water
(kg/m3
) (kg/m3
) (kg/m3
) Litre
1 413 600 1190 186
2 1 1.4 2.8 0.45
3. RESULTS AND DISCUSSION
3.1. Compressive and Split tensile Strength of Coir Fibre Concrete Cubes
The compressive strength of the coir Fibre concrete is tested on the three days with five different
percentage of coconut husk Fibre mixing, they are 0,2,4,6,8 percentage of Fibre is mixed with the
concrete cubes[5]. And three trials have been made the value of compressive strength is shown in the
table 4 with 7, 14 and 28 days of curing the concrete. The graphs have been plotted for the
compressive strength vs. percentage of coconut husk Fibre mixing. In the observation of the graph
shows that the less percentage of Fibre mixes increase the compressive strength values. The figure 1
shows the compressive strength testing machine for the concrete cube.
5. S. Sastha Arumuga Pandi, S. Yamini Roja, G. Jenitha and K. Alagusankareswari
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Figure 1 Compressive strength testingmachine for the concrete cube
Table 4 Compressive Strength of M30 Concrete – 7, 14 &28 Days Curing
Cocunu
t husk
fibre
Trial
s
Load
s in
Averag
e load
Compressiv
e strength
Load
s in
Averag
e load
Compressiv
e strength
Load
s in
Averag
e load
Compressiv
e strength
kN kN (N/mm2
) kN kN (N/mm2
) kN kN (N/mm2
)
7 days 14 days 28 days
0%
1 400
400 17.77
520
510 22.66
700
696.7 30.962 390 500 690
3 410 510 700
2%
1 400
393.3 17.5
530
536.7 23.85
700
710 31.552 380 530 710
3 400 550 720
4%
1 410
400 17.77
540
523.3 23.26
700
700 31.112 400 520 710
3 390 510 690
6%
1 380
370 16.44
510
480 21.33
680
683.3 30.372 370 470 700
3 360 460 670
8%
1 350
353.3 15.7
440
426.7 18.96
680
673.3 29.922 370 410 660
3 340 430 650
Figure 2 Compressive strength of the coir fibre concrete 7, 14 & 28 Days Curing
0% 2% 4% 6% 8%
28 Days 30.96 31.55 31.11 30.37 29.92
14 Days 22.66 23.85 23.26 21.33 18.96
7 Days 17.77 17.50 17.77 16.44 15.70
0
10
20
30
40
50
60
70
80
Compressivestrength
Compressive Strength of M30 Concrete
6. Experimental Study on Behavior of Coir Fibre Reinforced Concrete
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3.2. Split Tensile Strength of Coir Fibre Concrete Cylinder
The cylindrical specimen is placed horizontally between the loading surfaces of a compression testing
machine. Narrow packing strips of suitable material such as plywood is used to reduce the high
compression stresses. The load is applied without shock and increasing continuously at a rate of the
specimen. The load is increased till the specimen fails and the continuous load applied to the specimen
during the test is recorded, the figure 3 shows the split tensile testing machine for the concrete
cylinder.
Figure 3 Split tensile testingmachine for the concrete Cylinder.
The spilt tensile strength is done with cylinder and with the same percentage of fibres, in the table
5 the split tensile strength of the concrete is calculated with the cylinder formula2P/πDL and graph is
plotted with the split tensile strength vs. Fibre percentage. From the figure 2, the observation of the
graph shows that the less percentage of Fibre mixes increases the split tensile strength of the concrete.
Table 5 Split Tensile Strength of M30 Concrete – 7, 14 &28 Days Curing
Coconut husk
fibre
Load
Split tensile
strength
Load
Split tensile
strength
Load
Split tensile
strength
kN (N/mm2
) kN (N/mm2
) kN (N/mm2
)
7 Days 14 Days 28 Days
0% 110 1.56 150 2.12 200 2.83
2% 120 1.70 170 2.4 230 3.25
4% 100 1.41 160 2.26 210 2.97
6% 90 1.27 140 1.98 190 2.69
8% 60 0.85 120 1.7 160 2.26
Figure 4 Split Tensile strength of the coirfibre concrete – 7, 14 &28 Days Curing
0% 2% 4% 6% 8%
7 Days 1.56 1.7 1.41 1.27 0.85
14 Days 2.12 2.4 2.26 1.98 1.7
28 Days 2.83 3.25 2.97 2.69 2.26
0
0.5
1
1.5
2
2.5
3
3.5
SplitTensileStrength
Split Tensile Strength of M30 of Concrete
7. S. Sastha Arumuga Pandi, S. Yamini Roja, G. Jenitha and K. Alagusankareswari
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4. CONCLUSION
Thus, Fibre reinforce concrete used as high tensile strength than normal methods used in the fields. So
based on the above results. We conclude the Natural fibre concrete as high compressive strength
compared than OPC. The compressive strength and split tensile strength of the concrete increase
simultaneously on the addition of artificial fiber than the conventional concrete.
Further addition of coconut husk fiber tends to reduce the workability and compressive strength of
concrete. While in addition of coconut husk fibre the maximum compressive strength of 31.55 N/mm2
is observed at 2% of addition of fibre and increase in compressive strength is 1.90% than the
conventional concrete.
REFERENCES
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[6] IS 456:2000 Plain and Reinforced Concrete
[7] IS 2386: Part 1 Method of Test For Aggregate For Concrete
[8] IS10262:2009 Concrete Mix Proportioning Guidelines.
[9] IS 4031 Part 4 Methods Of Physical Tests For Hydraulic Cement (Determination Of Consistency
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[10] IS 4031 Part 5 Methods of Physical Tests For Hydraulic Cement (Determination of Initial and Final
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