28-08-2014, 03:37 PM
A Study On Optimising The Strength Of Concrete Using Green Materials Seminar Report
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ABSTRACT
India is a major agriculture wastage
producing country, and the generated husk during
milling is mostly used as a fuel in the boilers for
producing energy, processing paddy, through
direct combustion or by gasification. About the
million tonnes of Rice Husk Ash (RHA) and
Sugarcane Bagasse Ash (SCBA) is produced
annually. This RHA and SCBA is a great
environment threat causing damage to the land and
the surrounding area in which it is dumped. Many
ways are being thought of for disposing them by
making commercial use of this RHA, and SCBA. It
is wastage can be used as a replacement for
concrete (15 to 20%).
This paper evaluates how different contents of Rice
Husk Ash, Groundnut Shell Ash, and Sugarcane
Bagasse Ash added to concrete may influence its
physical and mechanical properties. Sample Cubes,
Cylinder were tested with different percentage of
RHA, SCBA and different w/c ratio, replacing in
mass of cement. Properties like Compressive
strength, Water Absorption, Split tensile strength,
Slump Retention is done. The grades of concrete
used were M20.
MATERAIAL AND METHODS
Rice Husk Ash
Rice husk ash is a major Agricultural product
obtained from paddy. For every 40 KN of rice 10
kN of husk is produced. The husk is disposed off by dumping it in an open heap near the mill site or
on the road side to be burnt later.
Burning the rice husk generated about 15-20% of
its weighing as ash. The ash being very light is
easily carried by wind and water contributing to air
and water pollution. The huge quantity of ash
generated requires large areas for disposal.
The high percentage of siliceous material present in
rice husk ash indicated that it has pozzolanic
properties. The normal method of conversion of
husk to ash is by incineration
Sugarcane Bagasse Ash
The Bagasse Ash is the fibrous waste
produced after the extraction of the sugar juice
from cane. This material usually causes a disposal
problem in sugar factories particularly in tropical
countries. In many of the tropical countries there
are substantial quantities of Bagasse (the fibrous
residue from the crushing the sugar cane) is rich in
amorphous silica indicated that it has pozzolanic
properties
Methodology
The next stage is to heat the treated RHA,
SCBA in an electric muffle furnace at a
temperature of 700oC for 4 hours in order to
produce the materials.
The result is then tested to determine the particle
size distribution of the ash in accordance with
Indian standard institution, which would pass
90microns sieve. Fineness test was carried out for
each sample by sieving the samples for 15 minutes
using the percentage of the residue by mass.
The mix ratio used for different nominal
replacement of OPC with RHA, SCBA and water
cement ratio weight.
The replacement levels of 15% to 20% by weight
of RHA, SCBA in the mass proportioning was used
to prepare the fresh concrete mix which are then
placed into the test cube moulds of 150mm x
150mm x 150mm. For each replacement level,
twenty test cubes were cast
Cube compressive strength
Cube compressive strength tests were carried
out on Cube specimens of the age of 7, 14 and 28
days curing, using compression testing machine of
3000 KN capacity. The test set up for compression
strength on Cube specimen is shown in Figure
Cylinder Splitting Tensile Strength
The tensile strength of the concrete specimens.
It shows that the tensile strength of concrete
specimens incorporated with 20% RHA and 15%
SCBA is lower at 7 days but similar at 14 and 28
days. This result shows that higher RHA amounts
will not increase the flexural and tensile strengths
of Grade 20 concrete.
Conclusion
The results show that the value of compressive
strength of Rice Husk Ash is M20 grade of
concrete ranged 20% replacement level of the
compressive strength of the control at the 28th day.
By using the OPC 53 grade, normal strength of
19.50MPa at 28-days can be obtained. The RHA
can partially replace cement by20%and give
ultimate strength of concrete. Its economical than
the normal concrete