1. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
ENGINEERING AND TECHNOLOGY (IJARET)
ISSN 0976 - 6480 (Print)
ISSN 0976 - 6499 (Online)
Volume 4, Issue 7, November-December 2013, pp. 20-24
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IJARET
©IAEME
STRENGTH PROPERTIES OF COCONUT SHELL CONCRETE
Dewanshu Ahlawat1,
L.G.Kalurkar2
1
2
Post Graduate Student, JNEC, Aurangabad, Maharashtra, India
Asst.Prof. in Civil Engineering Dept, JNEC, Aurangabad, Maharashtra, India
ABSTRACT
Continuous extraction of aggregates from natural resources will lead to its depletion. This
paper presents an experimental investigation on the effect of replacing granite with coconut shell on
the tensile strength and workability of concrete. Forty five cylinders were casted of M 20 grade of
concrete. The slump cone and compaction factor test were done to assess the workability of concrete.
The tensile strength of cured concrete was evaluated at 7, 14 and 28 days. Increase in percentage
replacement of granite lowered tensile strength, but increased workability. Concrete produced by
2.5%,5%,7.5%,10% replacement attained 28 days tensile strength of 1.31,1.25,1.16 and 1.09
respectively. The results showed that coconut shell concrete can be used in construction.
Keywords: Coconut Shell, Coarse Aggregate, Split Tensile Strength, Workability, waste utilization.
INTRODUCTION
Concrete is the premier civil engineering construction material. Concrete manufacturing
involves the mixing of ingredients like cement, sand, aggregates and water. Among all these
ingredients, aggregates form the big share [1]. Inert materials such as sand, granite forms the major
part of aggregates. Traditionally, aggregates have been readily available at economic prices and in
different forms to suit all purposes [2]. However, the continuous extraction of aggregates from the
natural resources has been questioned because of the depletion of quality aggregates and greater
awareness of environmental protection. In light of this, non availability of natural resources to the
future generation has been realized [3]. The challenge in making light weight concrete is in
decreasing the density, while maintaining the strength and durability. Introducing different types of
light aggregates (Pumice, Taclite, Coconut shell, sawdust, coal slag, straw) into the mix design is a
common way to lower the density of concrete [4]. The crushed stone and sand are the components
that are usually replaced with light weight aggregates to produce light weight concrete. One of the
fine examples of light weight aggregate is coconut shell. Coconut shell has good durability, high
20

2. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
toughness, abrasion resistance; hence it is suitable for long standing use [5]. Utilization of Coconut
shell as coarse aggregate will be an important step towards sustainable development. The study on
replacing waste material in concrete is not new. In India, 90% coconut production is in South India.
Tamil Nadu leads in coconut production in India because of high productivity of soil [6].
METHODOLOGY
•
•
•
•
Selection of grade of concrete, method of mix design, trial mix and final mix proportions.
Estimating total quantity of concrete required.
Estimating quantities of cement, water, sand and coarse aggregates.
Evaluating the physical properties of ingredients of concrete.
MATERIALS AND METHOD
Cement: Ordinary Portland cement, conforming to I.S 12269-1987[10] is the most commonly used
binder for the concrete production. The standard consistency was 29%.The initial and final setting time
was 55 mins and 270 mins respectively. The specific gravity of cement was 3.14.The basic field tests on
cement were conducted.
Fine Aggregate: River sand, conforming to Grading Zone- II as per I.S 383-1970[11] was used in the
study. The bulk density, specific gravity and fineness modulus of sand were determined. The sand was
air dried and sieved to remove any foreign material, prior to mixing.
Coarse Aggregate: Crushed granite stone and coconut shell were used as coarse aggregate. Various
physical and mechanical properties of coarse aggregates were checked and they included bulk density,
specific gravity, water absorption, aggregate impact test, crushing test, abrasion test,particle size
distribution.
Coconut Shell: Coconut shell were collected from the local temples, cleaned, sun dried, removed fibers
to analyze its properties. Coconut shell requires no pre treatment, except for water treatment. Coconut
shell has high water absorption. Due to this property, coconut shells were pre soaked in potable water for
24 hours.
Water: Potable water was used for mixing and curing. The permissible limits were checked as per the
I.S 456-2000[12].Water should be free from oil, salt, sugar, acid, alkali. The quality of water is
important because contaminants can adversely affect the strength of concrete and cause corrosion of
steel reinforcement.
Physical Property
Max.size
Moisture Content (%)
Water Absorption (%)
Specific Gravity
Impact Value (%)
Crushing Value (%)
Abrasion Value (%)
Bulk Density(kg/m3)
Fineness Modulus
Coconut Shell
12.5
4.10
25
1.4
7.9
2.6
1.7
800
-
Coarse Aggregate
12.5
0.25
2.8
11.2
6.5
1.9
1650
2.73
21
Fine Aggregate
2.6
1600
2.80

3. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
PRODUCTION OF CONCRETE MIX
The production of concrete mix of M-20 grade of concrete is done in the laboratory. For mix
design, I.S 10262-1982[9] method was used. Coconut shell concrete is produced by adding coconut
shell in different percentage (0%, 2.5%, 5%, 7.5%, and 10%).The ingredients of concrete were tested
as per I.S codes. A total of 45 cylinders were tested for split tensile strength and workability of
concrete and results were compared with conventional concrete. Batching is done as per mix
proportioning. Mixing is done in a tilting machine mixer. The mixing time is 2-3 minutes after
mixing of water. Compaction is done by tamping rod and table vibrator. Concrete cylinders are left
for 24 hours to set. After 24 hours, cylinders are demoulded with spanners and placed in curing tank.
It is being cured in potable water at room temperature for a period of 7, 14 and 28 days. After 28
days, these cylinders are removed from curing tank and are ready to be tested for split tensile
strength test.
WORKABILITY TESTS
Slump Cone Test: Workability is defined as the ease with which concrete can be compacted 100%
with respect to mode of compaction and placing. Unworkable concrete requires more efforts to be
compacted and honey comb structure is bound to occur. It is most widely used test for workability.
The apparatus used are slump cone, base plate, tamping rod, oil and scale. The types of slump are as
follows:
• Collapse: Here, concrete collapses completely.
• Shear: Here, top portion of concrete shears off and slips sideways.
• True: Here, concrete subsides, keeping more or less to shape.
Compaction Factor Test: This test is used to determine workability of fresh concrete as per IS:
1199-1959.This test is suitable for medium and low workability, but not for very low workable
concrete (below 0.71).It gives more information than slump test. It is used for maximum size of
aggregates up to 20mm.A large apparatus if size of aggregates is 40mm.The apparatus consists of a
rigid frame that supports two conical hoppers vertically aligned above each other, mounted over a
cylinder. The top hopper is slightly larger than bottom hopper, while the cylinder is smaller in
volume than both hoppers.
Split Tensile Strength Test: Concrete cylinders (150mm diameter x 300mm height) are casted.
Once the curing is done, the cylinders are cleaned and dried properly, before placing it in Universal
Testing Machine (U.T.M).The plate is lowered and allowed to touch the top surface of the cylinder.
The force is applied and is increasing continuously. The load at which splitting of the cylinder takes
place is recorded and split tensile strength is calculated. The concrete does not resist the direct
tension because of its low tensile strength and brittle nature. As we know that concrete is weak in
tension. However, determination of split tensile strength is necessary to determine the load at which
the concrete members may fail.
Calculations: T= 2P/ πdL
Where, P = Maximum load
d = Diameter of specimen
L = Length of specimen
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4. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
RESULTS AND DISCUSSION
1. Split tensile strength: The maximum tensile strength of 2.1 N/mm2 was attained at 0%
replacement, while minimum tensile strength of 1.74 N/mm2 was attained at 100%
replacement. The split tensile strength was found to be reducing with increasing coconut shell
percentage. The same was observed by the earlier researchers [7], [8]. The results of split
tensile strength are shown in table 01.
No. of Days
07
14
28
Table 01. Tensile Strength of Coconut Shell Concrete (N/mm2)
0%
2.5%
5%
7.5%
1.40
1.31
1.25
1.16
1.89
1.74
1.70
1.56
2.1
1.97
1.88
1.81
10%
1.09
1.51
1.74
2. Workability of Concrete: The results of workability of concrete are shown in table 02.There
is 30% cost reduction for concrete produced using coconut shell [8].
Workability
Slump (mm)
Compaction
Factor Value
Table 02. Workability of Coconut Shell Concrete
0%
2.5%
5%
7.5%
85
61
67
73
0.910
0.910
0.917
0.920
10%
79
0.924
Bar Charts: The bar charts are drawn for compressive strength results. These are drawn between
compressive strength and percentage replacement of coconut shell concrete at 7, 14 and 28 days to
observe the variation of results.
2
7 days
14 days
1.8
Tensile Strength MPa`
1.3
1.1
0.9
0% 2.50% 5% 7.50% 10%
% of coconut shell
1.6
1.4
1.2
0% 2.50% 5% 7.50% 10%
% of coconut shell replacement
2.3
28 days
Tensile strength MPa
Tensile Strength MPa
1.5
2.1
1.9
1.7
1.5
0% 2.50% 5% 7.50% 10%
% of coconut shell replacement
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5. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
CONCLUSION AND RECOMMENDATION
It is concluded that
• Increase in percentage replacement by coconut shell reduces split tensile strength of coconut
shell concrete.
• Slump of concrete increases as percentage of coconut shell increases.
• Compaction Factor increases as percentage of coconut shell increases.
• Coconut shell can be used as partial replacement of coarse aggregate in concrete.
The following recommendations are made at the end of study.
• The effect of temperature on Coconut Shell Concrete is studied.
• Durability aspects of Coconut Shell Concrete are studied.
• Drying shrinkage property of coconut shell concrete is studied.
REFERENCES
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aggregate replacement”,International Journal of Engineering Inventions,Vol.1,Issue6, pp21-31
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Coconut Shell Concrete”, Construction and Building Materials, 25(1), pp 92-98.
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concrete”, Proceeding of sixth structural engineering convention,Chennai,pp 1079-1087
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waste as aggregate”, International conference on low cost housing in developed countries,
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concrete”, International Journal of Applied Engineering Research,7(11),2012.
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engineering research and technology,Vol.2,Issue6,June 2013,pp 2405-2415.
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conventional concrete”, Vol.2, Issue 12, pp 67-70
9. I.S 10262-1982:”Recommended guidelines for concrete mix design”, 1982
10. I.S 12269-1987:”Specifications for 53 grade Ordinary Portland Cement”, 1987
11. I.S 383-1970:”Specifications for coarse and fine aggregates”, 1970
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