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Abstract

The construction industry has been using recycled aggregate to provide environmentally friendly and low cost concrete and save the natural resources. In this study, recycled aggregate (RA) has been used as replacement material for natural aggregate as a coarse aggregate in the concrete mixture. Uncontrolled Burnt Rice Husk Ash (UBRHA) has been replaced the cement in concrete mixture at different proportions for improving the properties of the recycled aggregate concrete. The performance of Recycled Aggregate Concrete (RAC) containing UBRHA, in the term of compressive strength, water absorption and ultrasonic pulse velocity has been investigated. In this study the recycled aggregate has been used in various percentages such as 0%, 50% and 100%, and UBRHA proportions from 0%, 5%, 10%, 15% and 20%. From this study, it was found that the compressive strength of RAC is decreases when RA percentage increases. However, the utilization of URBHA as cement replacement material could enhance the performance of recycled aggregate concrete. In this study, it was found that the optimum replacement for UBRHA is 5%. The compressive strength for concrete containing 5% UBRHA with 100% RA is 30.3MPa. Then, for water absorbtion, it was found that the water absorption for 5% UBRHA with 100% RA is 12.1%. Thus, it can be concluded that RAC containing URHBA could enhance the performance of RAC in term of compressive strength and water absorption. Also, from Ultrasonic Pulse Velocity testing, it could be considered that all specimens are durable concrete.