Properties of Ternary Cementitious Concrete Matrix Containing Rice Husk Ash and Coconut Husk Ash

Abstract

The environmental pollution resulting from the production process of cement has contributed to the climate change being experienced worldwide. The need to reduce the rate of depletion of the ozone layer and also to produce durable and sustainable concrete has led to this study. Eighty four (84) concrete cubes of 150 mm x 150 mm x 150 mm were produced with OPC /RHA / CHA blended concrete at percentage OPC replacement with pozzolans of 5%, 10%, 15% and 20%. Twenty one (21) concrete cubes were cast as control. Cubes from the concrete mixes were cured for 7, 14, 28, 35, 42, 49 and 56 days and were crushed to determine their compressive strengths. Experimental work was carried out on OPC/RHA /CHA concrete to determine their essential properties in fresh and hardened state, they are all within the limits specified by relevant standards. It was observed that at 10% replacement the maximum compressive strength of 32.9N/mm 2 was obtained for the ternary blended concrete of OPC /RHA /CHA at 56 days, representing 16.1% increase in strength over the 100% OPC concrete, indicating the optimal value of compressive strength attained. This indicate that RHA and CHA combination is an excellent pozzolans that can be utilize for both binary and ternary blended concrete production.