Engineering properties of lightweight masonry unit produced from waste expanded polystyrene (eps) and rice husk ash (rha)
The depletion of non-renewable resources has become an alarming issue nowadays. Many environmentalists and researchers have been investigating the use of waste materials as a renewable resource for use as raw materials in construction. This research reports on the potential use of waste rice husk...
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Format: | Thesis |
Language: | English |
Published: |
Universiti Malaysia Sarawak, (UNIMAS)
2012
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Subjects: | |
Online Access: | http://ir.unimas.my/id/eprint/10886/2/Ling%20Ing%20Hock.pdf http://ir.unimas.my/id/eprint/10886/ |
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Summary: | The depletion of non-renewable resources has become an alarming issue nowadays. Many
environmentalists and researchers have been investigating the use of waste materials as a
renewable resource for use as raw materials in construction. This research reports on the
potential use of waste rice husk ash (RHA) and expanded polystyrene (EPS) beads in producing
lightweight concrete bricks. The RHA was used as a cementitious material since it is a
lightweight reactive pozzolanic material. The mixes prepared were made of RHA of 5%, 10%,
15% and 20% as partial replacement for cement and with the same amounts of sand and EPSI
The EPS was used as partial aggregate replacement in the mixes. Four types of curing conditions
were employed in this study. These include water curing, air-dry, 3-day water curing and 7-day
water curing. The engineering properties of the bricks were investigated. Among the properties
studied were hardened density, dimension compliance, compressive strength, water absorption,
sorptivity and thermal conductivity of the EPS RHA concrete bricks. Scanning electron
microscopy (SEM) was also performed on the brick samples. The results showed that RIO with
10% RHA replacement was the optimum mix. It had an average 28-day air-dry density of 1745
kg/m3 which classifies it as lightweight. For the dimension compliance, all bricks were within the
specified values according to MS 76: 1972. In terms of compressive strength, it was found that
RIO not only gained the highest compressive strength as compared to other samples but also
complied with the Class 2 (14 N/mm2) requirement for load bearing bricks at 28 days as
specified in Malaysia Standard. The water absorption, sorptivity and thermal conductivity for
RIO at 28 days cured under different curing conditions ranged from 13% to 16%, 0.1 x 10-3
g/mm2/miri '5 to 0.142x 10-3 g/mm2/min°'5 and 0.36 W/mK to 0.468 W/mK respectively. In
addition, it was observed that there was a thermal conductivity reduction of approximately 31 %
as compared to control mix at 28 days which shows a significant amount of energy saving. The SEM analysis also showed denser microstructure arrangement for the RIO. It was found that the
properties of the bricks are mainly influenced by the percentage of RHA replacement in the mix
and also the curing condition used. The compressive strength of the EPS-RHA concrete brick
increased with the increase percentage of RHA replacement in the mix. RIO with 10% RHA
replacement (optimum mix) produced the highest compressive strength. The compressive
strength decreased as the percentage of RHA replacement exceeds 10%. The water absorption
and sorptivity values were decreased as the percentage of RHA replacement increased. The
increase in RHA replacement produced lower thermal conductivity values. In general, full water
curing is the most effective method of curing. It produced the highest level of compressive
strength and thermal conductivity but the lowest value of water absorption and sorptivity. |
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