This document analyzes the strength of concrete using manufactured sand (M-sand) and coconut shell as aggregates. M-sand and coconut shell can help address the shortage of natural river sand caused by over-mining. The compressive strength of concrete with 100% M-sand was higher than conventional concrete. Concrete with 20% coconut shell replacement had 9% lower density but nearly equal compressive strength to conventional concrete. Using M-sand and coconut shell can provide a sustainable alternative to conventional concrete aggregates.

1. STRENGTH ANALYSIS OF CONCRETE
USING M-SAND AND COCONUT SHELL
BY,
ALWIS DEVA KIRUPA J.P
1st YEAR ME (STRUCTURAL ENGINEERING)
REGIONAL CENTER OF ANNA UNIVERSITY,
THIRUNELVELI.

2. INTRODUCTION
Concrete is the widely used building material in
Civil Engineering constructions because of its
versatility.
River sand, a natural resource and a main
constituent of conventional concrete, is
increasingly depleting nowadays due to illicit sand
mining from river.
Dwindling sand resources poses the
environmental problem and hence government
restrictions on sand quarrying resulted in scarcity
and significant increase in its cost

3. Scarcity of natural sand due to heavy demand in
growing construction activities forces us to find
the suitable substitute.
Replacing fine aggregate by Manufactured sand
(M-sand) in concrete is a better solution for this
ecological imbalance and economic construction.
Utilizing coconut shell as coarse aggregate in
concrete production not only solves the problem of
disposing this solid waste but also helps to
conserve natural resources. Use of coconut shell in
concrete reduces its density.
The strength of the light weight concrete made by
using M-sand and coconut shell at certain
percentage is equal to the conventional concrete.

4. Materials used 1. CEMENT
For general purpose of ordinary Portland cement
43grade is suitable for the construction of all
engineering works.
Properties of ordinary Portland cement:-
As per IS 269-1967-1975 ,
The fineness residue does not exceed 10% on is
sieve no 90μ.
Soundness of ordinary Portland cement is not
more than 10mm in Le-chatterer apparatus.
Initial setting time is not less than 30 minutes.

5. Final setting time not more than 10 hours.
Compressive strength after 3days is not less
than11.5Nmm2.
Strength after 7 days is not less than 17.5Nmm2.
2. FINE AGGREGATE
2.1 River Sand
River sand shall conform to IS:383 and relevant
portion of IS:515.It shall pass through the 4.75mm
IS sieve leaving a residue of not more than 5%.
2.2 M-sand
M-sand is a term used for aggregate materials less
than 4.75mm size which are processed from
crushed rock or gravel.

6. The crushed sand or M-sand range should pass
through 10mm IS sieve and retain on 75μm IS sieve.
Fig 1. M-Sand

7. 3. COARSE AGGREGATE
3.1 Crushed or broken stone
It shall be obtained from crushing Granite, trap or
similar approved stone from approved quarry and
shall be conformed to IS 383 and IS 515. 95% of
which shall be retained on 4.75mm IS sieve. Size of
course aggregate shall be 20mm. Should be cubical
in shape.
3.2 Coconut shell
Coconut shell is one of agricultural by-product.
They were sun dried for 1 month before being
crushed manually. The crushed materials were later
taken to the lab where it is processed. The particle
size of the coconut shell is range from 5 to 20mm.

8. Fig 2. Coconut Shell

9. 4. WATER
Water used for mixing and curing shall be clean
free from oils, acids, alkalis, salts, sugar, organic
materials or other substances that may be
deleterious to concrete. Portable water is
generally considered satisfactory for mixing
concrete. Water used in concrete is of PH value is
not less than 6.

10. Mix design
The process of selecting suitable ingredients of
concrete and determining their relative amounts
with the objective of producing a concrete of the
required, strength, durability, and workability as
economically as possible, is termed the concrete
mix design.
 Factors affecting the mix design
Compressive Strength
Workability
Durability
Maximum Nominal Size of Aggregate
Grading and Type of Aggregate
Quality Control

11. PROCEDURE
 Design stipulations for proportioning
a. Grade designation: M20
b. Type of cement: OPC 43 grade, IS 8112
c. Max. nominal size of agg. : 20 mm
d. Minimum cement content: 320 kg/m3
e. Maximum water cement ratio: 0.55
f. Workability: 75 mm (slump)
g. Exposure condition: Mild
h. Degree of supervision: Good
i. Type of agg. : Crushed angular agg.
j. Maximum cement content: 450 kg/m3
k. Chemical admixture: Not used

12. 1. Target strength for mix proportioning
fck’= fck+ks
By Table 8 of IS 456 2000 standard deviation s = 4
Hence target strength = 20+1.65 x4 = 26.60 N/mm2
2. Selection of w/ c ratio
From Table 5 of IS 456:2000, maximum water
cement ratio = 0.55 (Mild exposure)
Based on experience, water cement ratio is 0.50
0.5 < 0.55. Hence, water cement ratio is 0.5
3. Selection of water content
From Table 2, maximum water content = 186 litre
Estimated water content for 75 mm slump
= 186 + 3/100 x 186 = 191.6 litres

13. 4. Calculation of cement content
Water cement ratio = 0.50
Cement content = 191.6/0.5
=383 kg/m3 >320 kg/m3 (given)
From Table 5 of IS 456, minimum cement content for
Mild exposure condition = 300 kg/m3
Hence Cement content is taken as 383kg/m3
5. Proportion of volume of coarse aggregate and
fine aggregate content
From Table 3, volume of coarse aggregate
corresponding to 20 mm size aggregate and fine
aggregate (Zone I) for water-cement ratio of 0.50
= 0.60

14. 6. Mix calculations
The mix calculations per unit volume of concrete
shall be as follows
a) Volume of concrete = 1 m3
b) Volume of cement =(mass of cement/specific
gravity of cement ) x (1/1000)
= [383.16/3.15] x [1/1000]
= 0.122 m3
c) Volume of water = [192/1] x [1/1000]
= 0.192 m3
d) Volume of all aggregates (e) = a – (b + c)
= 1 – (0.122 + 0.192) = 0.686 m3
e) Volume and weight of coarse aggregates
Volume = 0.686 x 0.6 = 0.412 m3
Weight = Volume of CA x specific gravity of CA
= 1103 kg

15. f) Volume and weight of fine aggregates
Volume = e x Volume of FA x specific gravity of FA
= 0.686 x 0.4 = 0.274 m3
Weight = Volume of FA x specific gravity of FA x1000
= 727 kg
7. Mix proportions for trial number 1
Cement = 383 kg/m3
Water = 191.6 kg/m3
Fine aggregate = 727 kg/m3
Coarse aggregates = 1103 kg/m3
Water cement ratio = 0.50
Yield = 2404.6 kg
Water : Cement : Fine aggregate : Coarse aggregate
191.6 : 383 : 727 : 1103
0.5 : 1 : 1.89 : 2.88
Mix ratio 1: 1.89: 2.88

16. Results & discussions
1. SPECIFIC GRAVITY
The specific gravity of fine aggregates and coarse
aggregates are shown in Table 1. The average specific
gravity of natural aggregates lies between 2.6 and 2.8.
Table 1 : Specific Gravity of Aggregates
Sample Specific gravity
River sand 2.46
M-sand 2.52
Coarse aggregate 2.61
Coconut shell 1.2

17. 2.46
2.52 2.61
1.2
3
2.5
2
1.5
1
0.5
0
River sand M-sand coarse agg. coconut shell
specific gravity
specific gravity
Fig 3. Specific Gravity of Aggregates

18. 2. SLUMP VALUE
Slump test was conducted on the fresh concrete. The slump
values of conventional concrete & M-sand with coconut shell
concrete are shown in table 2
Table 2 Slump Values of Conventional, M-Sand and Coconut
Shell Concretes
Designation Concrete sample Slump value (mm)
C Conventional concrete 63.33
A1 100% M-sand concrete 60
A2 100% M-sand + 30% CS 8.33
A3 100% M-sand + 20% CS 24
A4 100% M-sand + 10% CS 48.33

19. 70
60
50
40
30
20
10
0
63.33
60
48.33
slump in mm
24
8.33
C A1 A2 A3 A4
Fig 4. Slump Value of Conventional, M-sand and CS
Concretes

20. 3. DENSITY OF SAMPLE
The density of different concrete samples was
obtained as shown in table 3.
Table 3. Density of concrete Sample
Designation Concrete sample Density(kg/m3)
C Conventional concrete 2388
A1 100% M-sand concrete 2427
A2 100% M-sand + 30% CS 2244
A3 100% M-sand + 20% CS 2262
A4 100% M-sand + 10% CS 2296

21. The density of conventional concrete was obtained as
2388kg/m3. The density of M-sand concrete was found as 2427
kg/m3. When compared, it is 2% greater than conventional
concrete.
The density of 30% coconut shell concrete was found to be
2244kg/m3, it is 6% lesser than the density of conventional
concrete.
The density of 20% coconut shell concrete was found to be
2262kg/m3, it is 5% lesser than the density of conventional
concrete.
The density of 10% coconut shell concrete was found to be
2296kg/m3, it is 4% lesser than the density of conventional
concrete.
The variations of density of different concrete samples are
shown in figure 5

22. 2450
2400
2350
2300
2250
2200
2150
C A1 A2 A3 A4
DENSITY(KG/M3)
DENSITY
Fig 5. Density of Concrete Sample

23. 7 days compressive strength
(N/mm2)
21 days compressive
strength (N/mm2)
28 days compressive
strength (N/mm2)
Sampl
e 1
Samp
le 2
Samp
le
3
Averag
e
Sampl
e 1
Samp
le 2
Sampl
e
3
Averag
e
Sampl
e 1
Sample
2
Sample
3
18.22 17.78 19.56 18.52 23.56 24.22 23.33 23.72 25.56 24.44 26.22
23.77 24.66 24.22 24.22 28 30.89 28.44 29.11 36.67 35.56 36
13.11 13.33 13.56 13.33 21.11 20 20.67 20.59 22.22 21.56 22.67
15.56 15.11 15.56 15.41 23.78 24.44 22.44 23.56 25.33 25.11 24.67
18.67 19.33 19.11 19.04 25.78 26 24.89 25.56 27.11 26.67 27.78
Table 4. Compressive Strength of Different
Concrete Samples

24. 18.52
24.22
13.33
15.41
19.04
30
25
20
15
10
5
0
C A1 A2 A3 A4
COMPRESSIVE STRENGTH(N/퐦퐦2)
Fig 6 : 7 Days Compressive Strength

25. 23.72
29.11
20.59
23.56
25.56
35
30
25
20
15
10
5
0
C A1 A2 A3 A4
COMPRESSIVE STRENGTH(N/퐦퐦2)
Fig 7 : 21 Days Compressive Strength

26. 25.38
36.07
22.44
25.04
27.19
40
35
30
25
20
15
10
5
0
C A1 A2 A3 A4
COMPRESSIVE STRENGTH(N/퐦퐦2)
Fig 8 : 28 Days Compressive Strength

27. 40
35
30
25
20
15
10
5
0
C A1 A2 A3 A4
COMPRESSIVE STRENGTH(N/MM2)
7 DAYS COMPRESSIVE STRENGTH
21DAYS COMPRESSIVE STRENGTH
28DAYS COMPRESSIVE STRENGTH
Fig : 9 Comparison of 7, 21 and 28 Days Compressive
Strength

28. conclusion
The availability of river sand is very scarce
nowadays. M-sand fulfill the requirement of sand in
concrete.
The compressive strength of concrete using M-sand
is high when compared to concrete made by
river sand.
By replacing 20% coconut shell in place of
coarse aggregate, concrete has 9% lesser density
compared to conventional concrete.
Compressive strength of concrete made by using
the M-sand and 20% coconut shell is nearly equal
to the strength of conventional concrete.

29. The compressive strength of conventional concrete
was found as 25.38N/mm2 whereas the compressive
strength of full replaced M-sand concrete was found
as 36.07N/mm2.
While replacing 20% coarse aggregate by coconut
shell in M-sand concrete the strength was found as
25.04N/mm2. This value is nearly equal to the
conventional concrete and also that density was 5%
lesser than conventional concrete.

30. ..