Investigation of the optimum percentage of RHA to obtain maximum compressive strength of concrete

Abstract

Rice Husk Ash (RHA) is a byproduct of paddy rice. At the moment it is not taken a considerable use from that by product. So RHA adds as another waste to the environment. But now there is a trend to find the pozzolanic properties of RHA to enhance the properties of concrete. As a result, there are many researches were done to test the properties of RHA mixed concrete. And found that compressive strength of the RHA mixed concrete is increased in at any proportion of RHA mixing. But until today any one has not recommended that what is the optimum percentage of mixing RHA to concrete for gain maximum compressive strength with better durability performance. This research it is expected to find the optimum percentage for the mixing RHA to the OPC concrete as replacement basis to gain higher compressive strength and simultaneously it is expected to find corrosion performance and shrinkage performance of RHA mixed concrete. According to previous studies it has been found that with about 20% RHA replacement level is giving higher compressive strength. So here we expected to find the increment of compressive strength of 20%, 25% and 30% RHA replacement levels. At the moment we found 25% percentage of RHA replacement is also giving higher compressive strength. Also we expect compare the increment of 20% and 30% percentage replacement levels with above results. Also we are checking the shrinkage performance of RHA mixed concrete and normal OPC concrete in both indoor and outdoor condition. At the moment shrinkage performance of both RHA mixed and control sample has not significant difference and we expect to check for 90 days. Further we are checking the corrosion performance of RHA mixed concrete by using „Accelerated corrosion Test ‟ but after 45 days there is no any crack appeared either control sample or RHA mixed sample. So it expected that corrosion performance of RHA mixed concrete is also very close to the normal OPC concrete. Also we expected to do the „Rapid Chloride Penetration Test‟ to find the corrosion performance of RHA mixed concrete. Finally we hope to recommend optimum RHA mixed proportion to gain higher compressive strength with sufficient reliability.