Self-Compacting Concrete (SCC) is a flowing mixture that consolidates under its own weight and a highly workable concrete that can flow through densely reinforced and complex structural elements. The source material like a granular aggregate is often used in construction but difficult to find and the price is expensive. In developing country like Malaysia, the demand of natural sand is quite high to the rapid infrastructural growth. The aims for this paper is to study the effect of coal bottom ash on the replacement level of coal bottom ash as partial replacement of fine aggregate in SCC and to investigate the effect of coal bottom ash on the split tensile strength. The test involved designation of 0%, 10%, 20% and 30% of coal bottom ash (CBA) as a partial replacement of fine aggregate with variation of water cement ratio of 0.35, 0.40 and 0.45. The results shows that slump flow, Lbox ratio and sieve segregation resistance of SCC mixtures with CBA are decreased, while T 500 slump flow time increased with the increase of CBA replacement level. The highest tensile strength of SCC is 4.25 MPa achieved by control sample with the water cement ratio of 0.35 at the age 28 days. The increment of CBA replacement levels resulted in the reduction of split tensile strength and density of SCC. Meanwhile, the increment of water cement ratio was reduced the split tensile strength of SCC.
The influence of grinding on the physical properties of rice husk ash (RHA) and Portland cement is examined. The optimum rice husk ash grinding time (i.e. to produce a highly reactive product with minimum grinding energy) was determined. Eight different fineness grades of rice husk ash were examined and it was found that rice husk ash ground for the optimum grinding time had a median particle size of 9·52 μm. A rice husk ash dosage of 15% by weight of binder was used throughout the experiments. It was found that the specific gravity and the fineness of the rice husk ash increase with an increase in grinding time. However, the morphology of the rice husk ash changed with grinding. There appears to be an optimum grinding time of approximately 90 min, during which time the compressive strength and strength activity index increase significantly. The use of rice husk ash ground for 90 min (to 9·52 μm particle size) produced concrete with good strength and low porosity.
Foam concrete is a lightweight concrete which is produced relatively inexpensively. However, due to its low strength and brittleness the application in building construction is rather limited. A study has been undertaken to investigate the effects of polyolefin fibers at a relatively low volume fraction (0 %, 0.2 %, 0.4 % and 0.6 %) on the compressive and flexural properties of foamed concrete. The foamed concrete was designed to achieve a target strength of 8-10 MPa with a density of 1600 kg/m3 at the age of 28 days. For each mixture, nine lOOxlOOxlOO mm cubes and three 100x100x500 mm beam were prepared. The compressive test was performed on cubes and three points loading flexural test on the beams was carried out in accordance to MS 26:Part 2: 1991. Test results showed that polyolefin fibers only slightly improved the compressive strength and flexural strength of foamed concrete by 4.3% and 9.3% respectively.
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