ABSTRACT
The importance of concrete in modem society cannot be underestimated. There is no escaping from the impact of concrete on everyday life. Concrete is a composite material which is made of filler and a binder. Typical concrete is a mixture of fine aggregate (sand), coarse aggregate (rock), cement, and water. Nowadays the usage of concrete is increasing from time to time due to the rapid development of construction industry. The usage of concrete is not only in building construction but also in other areas such as road construction, bridges, harbor and many more. Thus technology in concrete has been developing in many ways to enhance the quality and properties of concrete. This study was made to investigate the nature of partial replacement of rice husk ash and grinded rice husk and its influences on the strength properties of concrete. Properties of hardened concrete like compressive strength and workability was determined for different mix combinations of materials and these values are compared with the corresponding values of conventional concrete. Ordinary Portland cement (OPC) was replaced with Rice Husk Ash (RHA) by weight at 0%, 10%, 20% and 30% and Grinded rice husk (GRH) by weight at 10%, 20% and 30%. The slump value obtained from the control mix was 50 mm while cement partially replaced by RHA at 10 %, 20%, and 30% were 60 mm, 68 mm, and 76 mm respectively and cement partially replaced by GRH at 10 %, 20% and 30% were 32 mm, 15 mm, and 5 mm respectively. The control mix at 40 days has a peak compressive strength of 49.07 N/mm2 while cement partially replaced by RHA at 10 %, 20%, 30% were 50.24 N/mm2, 40.53 N/mm2, and 40.20 N/mm2 respectively and cement partially replaced by GRH at 10 % was 45.47 N/mm2 at 40 days. The cement partially replaced by GRH at 20 % and 30% failed 3it the casting stage. This research concludes that 10% RHA is the optimum content for getting nearly equal strength at 40 days. Replacement of cement with Rice Husk Ash leads to increase in the compressive strength improved the workability and achieved the target strength, at 10% replacement for the grade of concrete.