The study aimed to seek for alternative use of crumb waste rubber tires (CWRT) in construction to lessen its environmental impact. Its use as a component in concrete has resulted in reduced mechanical and durability performance. On the other hand, rice husk ash (RHA), when used in conjunction with ordinary Portland cement improves the mechanical properties of concrete. Hence, to exploit this influence of RHA to strength, this study incorporated RHA in concrete to compensate for the strength

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... ction brought about by the inclusion of CWRT, as partial replacement to fine aggregates. RHA is also a by-product of agricultural waste thus, to maximize its potential as a cementitious material, an optimized process was developed for the study. Controlled burning and grinding were employed to maximize the pozzolanic properties obtained from RHA. Chemical treatment of CWRT has not resulted in a significant increase in strength for mortar specimens thus, treatment was not employed for CWRT used in concrete. Compressive strength was tested for concrete with varying CWRT ranging from 5 to 20% fine aggregate replacement. RHA replacement of cement was fixed at 10% based on the result of an earlier related study. Concrete with 10% RHA and 5% CWRT was found to be the optimal mix with a 9.5% increase in strength compared to normal concrete.