Construction industry is the second largest industry in the world due to rapid growth in the constriction lots of waste are generated in many of the places in the world. There might be some specific dumping point or land filling process is a there but most of the concrete wastes dumping unclearly throwing and dumping out from the site after the constriction or demolition a damaged building or in a specific reason to demolishing a building all aspects lots of concrete waste are produced in order to this we are planning to partial replacement of concrete waste with rick husk ash as a replacement material to check the properties of concrete. We choose one demolished building site and collected concrete waste to check the present properties of the material like compressive strength and flexural properties, specific gravity etc. After the concrete replacement with rice husk to identify the overall properties of the collected samples.

1. RECYCLING OF CONCRETE FROM DEMOLISHED
CONSTRUCTION WASTE
VISHNU VIJAYAN
Assistant Professor and HOD, Baselios Mathews II College of Engineering, Kerala, India
MEGHA.R.NAIR
Final Year B.Tech Student Department of Civil Engineering, Baselios Mathews II College of Engineering,
Kerala, India
ANJITHA.S
Final Year B.Tech Student, Department of Civil Engineering, Baselios Mathews II College of Engineering,
Kerala, India
MALU.O
Final Year B.Tech Student Department of Civil Engineering, Baselios Mathews II College of Engineering,
Kerala, India
TIJOSAJAN
Final Year B.Tech Student ,Department of Civil Engineering, Baselios Mathews II College of Engineering,
Kerala, India
ABSTRACT
Construction industry is the second largest industry in the world due to rapid growth in the constriction lots of waste are
generated in many of the places in the world. There might be some specific dumping point or land filling process is a there
but most of the concrete wastes dumping unclearly throwing and dumping out from the site after the constriction or
demolition a damaged building or in a specific reason to demolishing a building all aspects lots of concrete waste are
produced in order to this we are planning to partial replacement of concrete waste with rick husk ash as a replacement
material to check the properties of concrete. We choose one demolished building site and collected concrete waste to check
the present properties of the material like compressive strength and flexural properties, specific gravity etc. After the
concrete replacement with rice husk to identify the overall properties of the collected samples.
Keywords: Demolition, Coastal Regulation zone, Construction Demolition wastes, Coarse aggregate
Mukt Shabd Journal
Volume IX, Issue VI, JUNE/2020
ISSN NO : 2347-3150
Page No : 3051

2. 1. INTRODUCTION
Rice husk ash is a carbon imparted green supplementary material and which is the by-product of rice
mill. Rice husk ash is a super pozzolanic reactive material which helps to improves the surface area of
transition zone between the microscopic structure of cement paste & aggregate in the high performance
concrete. Rice husk ash can be used as an admixture to make the concrete resistant against chemical
penetration as well for water proofing. Rice husk ash as a partial replacement of cement in high strength
concrete containing micro silica. It has dual roles like substitute for cement in concrete manufacturing
and reduces the price and weight of concrete in the production of low cost building blocks. Rice husk ash
is a porous material so due to increase in the percentage of RHA, there is an increment in water cement
ratio. The chemical properties of rice husk ash is affected due to high temperature. Rice husk ash is a
local additive helps to reduce the high cost of structural concrete. The replacement of cement can be done
partially in the proportion of 0.5%, 1% or even to 20% in the mix. Rice husk ash helps to increase the
properties of concrete. It is an agricultural residue so easily available.
Fig: Rice Husk
Physical properties of RHA
Table 1: Physical properties
S.No Particular Properties
1 Color Gray
2 Shape Texture Irregular
3 Mineralogy Non Crystalline
4 Particle Size < 45 microns
5 Specific Gravity 2.37
6 Odor Odorless
Mukt Shabd Journal
Volume IX, Issue VI, JUNE/2020
ISSN NO : 2347-3150
Page No : 3052

3. 1.1. ADVANTAGES OF RICE HUSK ASH(RHA)
RHA is a pozzolanic material which is generated in the rice mills in large quantities.
 It helps to provide durability to the concrete
 It provides large compressive strength
 It helps to reduce the environmental pollution
 It can be a partial substitute for OPC
 It can be used as admixture in concrete
1.2 OBJECTIVES OF THE STUDY
Following are the major specific objectives:
 To evaluate the mechanical strength characteristics like compressive strength, flexural strength and
splitting tensile strength and comparing with the conventional concrete
 The concrete mix is designed with varying percentages of rice husk ash by the partial replacement of OPC
 To compare the strength of concrete by the replacement of cement with RHA
1.3. APPLICATION OF RICE HUSK ASH
RHA in amorphous forms can be used as a partial substitute for OPC. The substitution can be from 0% to 20%.
RHA has so many applications like:
 It can be used in high performance concrete
 It can be used in making green concrete
 It can be used as oil spill absorbent
 As insulators
 It can be used in water proofing chemicals
1.4. METHODOLOGY
1.5. PREPARATION OF SPECIMEN
The fresh concrete is prepared by the partial replacement of ordinary Portland cement with rice husk ash. The substitution
can be from 0% to 20%. Then it is casted to five concrete cube specimens with 0%,5%,10%,15% and 20% rice husk ash by
the replacement of OPC for conducting the tests like compressive strength, flexural strength and splitting tensile strength.
The cube specimen is of size 150*150*150mm.
1.6. EXPERIMENTAL RESULTS
1.6.1. COMPRESSIVE STRENGTH TEST
The compressive strength test was conducted on a 150*150*150mm cube specimen after being cured for a period of 7 days
and 28 days. The following table and graph shows the compressive strength of concrete by partial replacement with rice
husk ash.
Mukt Shabd Journal
Volume IX, Issue VI, JUNE/2020
ISSN NO : 2347-3150
Page No : 3053

4. Table 2: Results for compressive strength
0, 11.76
5, 12.69 10, 12.87
15, 14.02
20, 11
0, 19.87
5, 22.15
10, 23.46
15, 25.87
20, 17.57
0
5
10
15
20
25
30
0 5 10 15 20 25
CompressiveStrength(Mpa)
Percentage of RHA (%)
7 DAYS
28 DAYS
Fig 1: Graph of Compressive Strength Test
1.6.2. FLEXURAL STRENGTH TEST
Table 3: Results of flexural strength test
FLEXURE STRENGTH OF DIFFERENT RICE HUSK ASH CONCRETE MIX (N/mm2)
Mix 7 days 28 days
Flexure Strength Increase/Decrease in
Strength
Flexure Strength Increase/Decrease in
Strength
RT-0 2.38 0 4.45
RT-1 2.95 23.94% 4.61 3.59%
RT-2 2.15 -27.11% 4.53 -1.73%
RT-3 1.65 -23.25% 3.48 -23.17%
RT-4 1.36 -21.24% 2.23 -35.91%
RT-5 1.2 -11.00% 1.8 -23.88%
SR.NO RHA percentage Compressive strength at 7 days (MPa) Compressive strength at 28 days (MPa)
1 0% 11.76 19.87
2 5% 12.69 22.15
3 10% 12.87 23.46
4 15% 14.02 25.87
5 20% 11.00 17.57
Mukt Shabd Journal
Volume IX, Issue VI, JUNE/2020
ISSN NO : 2347-3150
Page No : 3054

5. 1.6.3. SPLITTING TENSILE STRENGTH TEST
The split tensile strength of the concrete mix was carried out and the following table and graph provides the values of the
specimen after being cured for a interval of 7 and 28 days
Table 4: Results of split tensile strength test
SR.NO RHA
percentage
Split tensile strength at 7
days (MPa)
Split tensile strength
at 28 days (MPa)
1 0% 2.31 2.68
2 5% 2.03 2.73
3 10% 2.26 3.36
4 15% 1.79 2.87
5 20% 1.43 2.19
0, 2.31
5, 2.03
10, 2.26
15, 1.79
20, 1.43
0, 2.68 5, 2.73
10, 3.36
15, 2.87
20, 2.19
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25
SplitStrength
Percentage of RHA (%)
7 DAYS
28 DAYS
Fig 2: Graph Of Splitting Tensile Strength
1.7. CONCLUSION
 The compressive strength of concrete increased upto a 15% of RHA and found to be decreasing after the increasing
percentage of RHA.
 The workability of concrete with 5% of RHA found to be decreasing with increasing water/cement ratio when
compared with conventional concrete.
 The compaction factor as well been decreased with the increase in percentage of RHA
The flexural strength has been increased upto 1.79%of RHA compared to normal concrete and decreased in the strength
mixes of 21.7%, 49.88% and 59.55% respectively
Mukt Shabd Journal
Volume IX, Issue VI, JUNE/2020
ISSN NO : 2347-3150
Page No : 3055

6. REFERENCES
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Mukt Shabd Journal
Volume IX, Issue VI, JUNE/2020
ISSN NO : 2347-3150
Page No : 3056