Umudike Journal of Engineering and Technology

This study investigates the effects of Rice Husk Ash (RHA) on the strength and shrinkage properties of Concrete. Rice Husk is an agro- waste which when burnt under a controlled temperature, the ash produced owing to its rich content in silica is used as a super-pozzolanic material for the partial replacement of Ordinary Portland Cement (OPC) in concrete. Concrete mix proportion of 1:1.5:3 by weight with a constant water-cement ratio of 0.5 was used. The compressive strength was found to increase from 22.37N/mm at 7- day to 32.12 N/m2 at 28 -day (i.e. 43.6 % increment) for the control mix. The flexural strength results obtained at 28-day were 3.38, 3.44, 3.67, 3.50, 3.25, 2.96, 2.90 N/mm at replacement percentages of 0, 5, 10, 15, 20, 25 and 30% respectively. Results of tests on the drying shrinkage of RHA concrete revealed that the 30% replacement level exhibited the highest shrinkage strain value of 440 microstrain compared to the control experiment with 380 microstrain at the 90-day period. This study suggests that up to 10% OPC replacement with RHA has the potential to be used for the partial replacement of cement in concrete for structural applications.