Influence of Elemental Variants of Rice Husk Ash (RHA) On Concrete Strength and Modulus of Elasticity

Abstract

This paper presents the effects of differentials in the elemental composition of Rice Husk Ash (RHA) sourced from four (4) locations on the compressive strength and modulus of elasticity of Concrete. The modulus of elasticity of concrete is a measurement of the stiffness of the concrete which is a good indicator of strength. RHA was sourced from four locations of Ogoja, Abakaliki, Adani and Adikpo in Nigeria and their silica content found to be 84.55, 76.3, 70.12, 70.11, respectively. RHA was used to replace cement in concrete at 5, 10,15,20,25 and 30%. The compressive strength values at 28 days was found to be in the range of 37-42N/mm² at 5%RHA, 35-39.5N/mm² at 10%RHA, 30-34.5N/mm² at 15%RHA, 27-29N/mm² at 20%RHA, 22-25.6N/mm² at 25% RHA and 21-24N/mm² at 30% RHA while the controlled sample had a strength value of 42.64N/mm². Short Cylindrical columns were cast and tested for tensile strength. The values of the tensile test are as follows; 3.15-3.7N/mm² at 5%RHA, 2.41-2.75 N/mm² at 10% RHA, 2.0-2.40 N/mm² at 15% RHA, 1.9-2.0 N/mm² at 20%RHA, 1.26-1.85 N/mm² at 25% RHA and 0.90-1.2 N/mm² at 30% RHA while the results of the controlled sample is 3.84 N/mm².From the results above it can be deduced that the location source and the chemical elemental variants of RHA based on location affects the strength of concrete and its modulus of elasticity.