International Journal of Engineering Trends and Technology (IJETT) – Volume 35 Number 2- May 2016
Use of Glass and Coconut Fibres in Enhancing
Properties of Concrete
Rajeev Banerjee#1, S ArshadRazaNaqvi*2, Swati Srivastava*3
#
*
Assistant Professor, Department of Civil Engineering, Integral University, Lucknow-226026 (India)
Post Graduate student, Department of Civil Engineering, Integral University, Lucknow-226026 (India)
Abstract:Compared to other binding materials the
tensile strength of concrete is relatively low. The use
of various fibres increases structural integrity of
concrete. Individual work has been done on Coconut
and Glass fibres but no investigation is done on its
combined usage. In the present investigation, the
compressive strength, tensile strength and workability
of concrete is studied by adding glass fibreand
coconut fibreto concrete. The result of these
parameters compared to those of standard M20 grade
concrete. Based on results achieved at laboratory, the
compressive and tensile strength increased by 24%
and 33.5% respectively. However, significant
reduction in workability of GFRC was observed with
increase in glass fibre content. The preliminary
investigation reveals that there is a vast scope in using
glass and coconut fibre combined and in the coming
future,
structural
glass
fibreand
coconut
fibrereinforced concrete shall provide a simple and
visually appealing alternative to conventional steel
bar.
Keywords: —Compressive Strength, Split Tensile
Strength, Glass Fibres, Coconut Fibres, Grade of
concrete.
I. INTRODUCTION:
The importance of concrete in modern
society cannot be overestimated. It is used in almost
every type of structure that we build today. Concrete
is a composite material which is made of filler and a
binder. The binder (cement paste) “glues” and the
filler together to form a synthetic conglomerate. The
constituent used for the binder are cement and water,
while the filler can be fine or coarse aggregate.
Despite of its high usage concrete has certain
limitations that are concrete possess low ensile
strength, due to drying and shrinkage and moisture
expansion concrete may crack, it is less ductile etc.
These limitations can be rectify by using certain type
of fibres available in market with abundance and low
price such as glass, basalt, coconut, polypropolene etc.
Glass fibre reinforced concrete (GFRC) was
first introduced to the building industry in the early
1970’s in the United Kingdom. It is a composite of
Portland cement, fine aggregate, water, acrylic copolymer, glass fibre reinforcement and additives. The
ISSN: 2231-5381
glass fibre reinforces the concrete, much as steel
reinforcing doesin conventional concrete. The glass
fibre reinforcement results in a product with much
higher flexural and tensile strengths than normal
concrete, allowing its use in thin wall casting
applications. Some benefits of GFRC are it is highly
durable and safe, requires very low maintenance,
installation is quick and cost effective, economical
etc.Experiments have been carried out by several
researchers using glass fibres in different ratios. Gowri
et al conducted study to investigate the effect of glass
wool fibres on Mechanical properties of concrete[1].
Murthy et al conducted study on performance of Glass
Fibre Reinforced Concrete[2].Chandramouli et al
reported the results of an experimental study on
Strength Properties of Glass Fibre Concrete[3].Kene et
al conducted study on Experimental Study on
Behaviour of Steel and Glass Fibre Reinforced
Concrete Composites[4].
Coconut fibres obtained from coconut husk,
belonging to the family of palm fibres, are agricultural
waste products obtained in the processing of coconut
oil, and are available in large quantities in the tropical
regions of the world, most especially in Africa, Asia
and southern America. Coconut fibre has been used to
enhance concrete and mortar, and has proven to
improve the toughness of the concrete and mortar. In
present study the coconut fibres with diameter ranging
between 0.10mm and 0.40mm and length between
6mm and 24mm and approximate mean aspect ratio of
150 is used.Sen et al reported the results on
Application of Sisal, Bamboo, Coir and Jute
NaturalComposites
in
Structural
upgradation[5].Agrawal et al studied the effect of
coconut fibres in concrete to enhance its Strength
and making Lightweight Concrete[6]. Shreeshail et
alhas been established that fibres when added in
certain percentage in concrete improve the
mechanical properties of concrete[7].
II EXPERIMENTAL INVESTIGATION
The experimental Programme involves various
processes of material testing, mix proportioning,
mixing, casting and curing of test specimens which is
elaborated in the following sections. All the
experiments were done in the material testing
laboratory, Integral University Lucknow and Bansal
Institute of Engineering and Technology, Lucknow.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 35 Number 2- May 2016
A. Materials Used
Cement, sand, coarse aggregate, water and glass
fibres were used in the design of concrete mix.
Physical properties were tested in the lab are
illustrated below:
1) Cement: Ordinary Portland cement of 43
grades was used,conformingto recommendations
stated in IS 4031(1999). The normal consistency was
30%. Initial and final setting time of the cement was
30 min and 610 min, respectively. The fineness comes
out to be 1.31%
2) Sand: Coarse sand locally available in the
market was used as fine aggregate. Locally available
sand, confirming to zone I with specific gravity 2.632,
water absorption 2% and fineness modulus 3.173.
The test procedures as mentioned in IS-383(1970)
were followed to determine the physical properties of
sand.
3) Coarse Aggregate:Two single sized crushed
stone aggregates ranging from 12.5 mm to 2.36 mm
and 20 mm to 4.75 mm (10mm and 20mm sizes) were
used in respective proportions in concrete mixes. The
test procedures as mentioned in IS-383(1970) were
followed to determine the physical properties of
sand.The results obtained are tabulated in Table 1
TABLE I
PHYSICAL PROPERTIES OF COURSE AGGREGATE
Physical Properties
Observed Values
10mm
20mm
aggregate
aggregate
6.30
7.10
2.74
2.71
19.20
26.32
Fineness Modulus
Specific Gravity
Aggregate Crushing
Value (%)
Aggregate Impact
29.32
21.05
Value
.
4) Glass Fibre:Cem-Fil Anti-Crack, HD-12mm,
Alkali Resistant glass fibres were used throughout the
experimental work. From the micro to the macro fibre
range, these fibres control the cracking processes that
can take place during the life-span of concrete. The
specifications of these fibres are presented in Table 2.
5)
Coconut Fibre:
The
locally available coconut fibres were used in the
experimental work. The fibres were collected and
brought to fine fibres by manually.
TABLE III
PHYSICAL PROPERTIES OF COCONUT FIBRE
Property
Diameter(mm)
Density(gm/cm3)
Natural moisture content (% )
Value
0.1-0.4
0.67-1
11.44-15.85
Water absorption (%)
Tensile strength (MPa)
Modulus of elasticity (GPa )
85-135
108.26-251.90
2.5-4.5
Strain at failure (%)
13.7-41.0
6) Water:The Water used for mixing concrete
should be portable drinking water having pH value of
7 and the water is free from organic matter and the
solid contents should be within the permissible limits
as per IS 456-2000 & and conforming to IS
3025.1964.
B. Concrete Mix Proportions
The mixture proportioning was done
according the Indian Standard Recommended Method
IS 10262- 2009 [8] and with reference to IS 456-2000
[9]. The target mean strength was 26.6MPa for the
OPC control mixture, the total binder content was 361
Kg/m3, fine aggregate was taken 826 Kg/ m3 and
coarse aggregate was taken 1138 Kg/m3. The water to
binder ratio was kept constant as 0.45. The total
mixing time was 5 minutes; the samples were then
casted and left for 24 hrs before demoulding. They
were then placed in the curing tank until the day of
testing cement, sand and coarse aggregate were
properly mixed together in the ratio 1.0:2.28:3.14 by
weight before water was added and properly mixed
together to achieve homogenous material. Cube and
cylindrical moulds were used for casting. The
specimens with and without fibre were cured in the
tank for 7 and 28days.
TABLE II
PHYSICAL PROPERTIES OF GLASS FIBRE
Physical Properties
Specific gravity
Elastic Modulus (Gpa)
Tensile Strength (Mpa)
Length (mm)
Recommended values
by theSupplier
2.68
72
1700
12
Fig. 1 casting cylinder for Tensile Strength Test
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International Journal of Engineering Trends and Technology (IJETT) – Volume 35 Number 2- May 2016
Concrete for M20 grade were prepared as per
I.S.10262:2009 with w/c 0.45
TABLE IV
DETAILS OF QUANTITY OF CONSTITUENT MATERIALS
Material
Quantity
Proportion
Cement
Sand
Coarse
Aggregate
Water
361.87 Kg/m3
826.10 Kg/m3
1138.72 Kg/m3
1
2.28
3.14
162.84 Kg/m3
0.45
IV. RESULTS AND DISCUSSION
The results obtained are presented in Table 5.
Result shows that as the percentage of glass fibres
increases in the mix there is corresponding increase in
the strength. Apart from this workability of the mixes
is also affected by the addition of fibres.
TABLE V
RESULTS OF COMPRESSIVE STRENGTH OF COCONUT
FIBRE REINFORCED CONCRETE FOR M-20
S. No
Mix
No
% of
Coconut
1
2
3
4
5
6
M-0
M-1
M-2
M-3
M-4
M-5
0.00
0.5
1.0
1.5
2.0
2.5
III. METHODOLOGY
The tests have been performed to determine the
mechanical properties such as compressive strength
and splitting tensile-strength of hardened concrete and
workability for fresh concrete.
A. Workability Test
Workability tests were performed using Slump
moulds as it is the quick measure of workability of
concrete mixes. The slump test was done in
accordance with the IS 1199-1959.
B. Compressive Strength Test
One of the most important and useful property of
concrete is its compressive strength. Compressive
strength test was performed according to IS 516:1959
[10]. Cubes of specimen of size 150 mm x 150 mm x
150 mm were prepared for each mix. The compression
test was conducted on cube specimens cured for 7 &
28 days. The test cubes were removed from the moist
storage 24 hours before testing. The top and bottom
bearing plates of the compression testing machine
were wiped and cleaned before the placement of the
specimen. The load was applied until the concrete
specimens failed and the ultimate load was noted. The
compressive strength reported is the average of three
results obtained from three identical cubes.
C. Split Tensile Strength Test
The tensile strength is one of the basic and
important properties of the concrete. The splitting tests
are well known indirect tests used for determining the
tensile strength of concrete. The test was performed
according to the procedure adopted in IS 5816:1999
[11]. Cylinders of specimen size 150 mm x 300 mm
were prepared for each mixes. The tensile test was
conducted on cube specimens cured for 7 & 28 days.
The test cylinders were removed from the water tank
24 hours before testing. The test consists of applying a
compressive line load along the opposite generators of
a concrete cylinder placed with its axis horizontal
between the compressive platens.
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Compressive
Strength (Mpa)
7 Days
28 Days
15.15
29.13
15.30
29.65
16.10
31.56
16.76
33.56
17.23
33.96
16.95
32.56
TABLE VI
RESULTS OF COMPRESSIVE STRENGTH OF GLASS
FIBRE REINFORCED CONCRETE FOR M-20
S. No
Mix
No
% of
Glass
1
2
3
4
5
M-O
M-6
M-7
M-8
M-9
0.00
0.02
0.04
0.06
0.08
Compressive
Strength(Mpa)
7 Days
28 Days
15.15
29.13
15.32
29.89
15.92
31.45
16.64
33.80
16.94
35.06
TABLE VII
RESULTS OF COMPRESSIVE STRENGTH OF GLASS AND
COCONUT FIBRE REINFORCED CONCRETE FOR M-20
S.
No
Mix.
No
% of
Glass
% of
Coco
nut
Compressive
Strength (Mpa)
7 Days
1
2
3
4
5
M-0
M-10
M-11
M-12
M-13
0.00
0.02
0.04
0.06
0.08
0.00
1.00
1.00
1.00
1.00
15.15
19.73
20.43
21.76
21.89
28
Days
29.13
30.95
33.56
35.12
36.12
TABLE VIII
RESULTS OF TENSILE STRENGTH OF GLASS AND
COCONUT FIBRE REINFORCED CONCRETE FOR M-20
S.
No
Mix.
No
% of
Glass
% of
Coco
nut
Tensile Strength
(Mpa)
7 Days
1
2
3
4
5
M-0
M-10
M-11
M-12
M-13
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0.00
0.02
0.04
0.06
0.08
0.00
1.00
1.00
1.00
1.00
2.36
2.41
2.64
3.06
3.711
28
Days
3.28
3.52
3.82
4.26
4.38
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International Journal of Engineering Trends and Technology (IJETT) – Volume 35 Number 2- May 2016
A. Effect of percentage of fibres
compressive strength of concrete
on
The compressive strength of concrete mix
was observed to be increasing using Glass and
Coconut fibre combined compared to using Glass and
Coconut fibre individually. The addition of 2.5%
coconut fibre increases Compressive Strength to
11.70% while addition of 0.08% Glass fibre increases
Compressive Strength to 20.30%. On combined usage
i.e 1.00% Coconut fibre and 0.08% Glass fibre in
concrete increases to 23.99% for 28 days. This clearly
implies that as we go for combined usage of
thesefibres Compressive Strength increases more
compared to individual usage.
B. Effect of percentage of fibres
compressive strength of concrete
Fig. 4 Effect on Compressive Strength of Concrete on using Glass
and Coconut combined
on
The result shows that there is a significant
improvement in the tensile strength of concrete with
the addition of Glass and Coconut fibres. Addition of
0.02% glass fibreand 1.00% of Coconut Fibres
increases the tensile strength to 7.31%. Further
addition of 0.04% of fibres and 1.00% of Coconut
fibres increases the tensile strength to 16.46%.This
shows that as we go for higher percentage of these
fibres in concrete, tensile strength increases rapidly.
Fig.2 Effect of percentage of coconutfibres on compressive strength
of concrete
Fig. 5 Effect on Compressive Strength of Concrete on using Glass
and Coconut combined
VI. CONCLUSIONS
The present work deals with glass and Coconut fibre
used in concrete to enhance the mechanical properties
of concrete. The compressive strength of concrete
increases on addition of coconut fibre[up to 2%
]which is 16.58% of the conventional mix beyond that
it decreases so it is concluded that it should not be
used beyond 2%.The compressive strength of concrete
on addition of Glass fibre shows an increasing trend
and it is max for 0.08% ie 20.35%.On combined usage
of Glass and Coconut fibre the compressive strength
increases up to 24% with glass fibre as .08% and
Coconut fibre as 1%. The tensile strength increases up
to 33.5% on adding glass fibre and Coconut fibre to
concrete.It has been observed that the workability of
concrete decreases with the addition of Glass fibres.
But this difficulty can be overcome by using
plasticizers or super-plasticizers.
ACKNOWLEDGEMENT
The authors acknowledge the help provided by the
academic teaching and non teaching staff of Integral
University as well as Bansal Institute in completion of
this project.
Fig. 3 Effect of percentage of Glassfibres on compressive strength
of concrete
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International Journal of Engineering Trends and Technology (IJETT) – Volume 35 Number 2- May 2016
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