Strength Characteristics of Concrete made with Rice Husk Ash as Partial Replacement of Cement using Periwinkle Shell as Coarse Aggregate.

Abstract

This research is aimed at determining the strength characteristic of rice husk ash /ordinary Portland cement/( RHA /OPC) concrete using periwinkle shell as aggregate. Three mix proportions of 1:1:2, 1:2:4 and 1:3:6 with water/cement ratio of 0:7 were used. The level of percentage replacement of cement with RHA varied with percentage replacement of 0, 30, 40 and 50 adopted in the course of the work. The mix proportion where properly cured and crushed at 7, 14,21and 28 days respectively. RHA was determined to have a specific gravity of 2.07 with bulk density of 726kg/m3 while the specific gravity of periwinkle shell was determined to be 2.07 with average bulk density of 553kg/m3 and was therefore classified as light weight aggregate. Compressive strength test taking on the cubes cast shows strength values decreasing with increase in RHA content and increasing with age. Values of compressive strength obtained at the 28th day hydration period ranges between 3.64-17.96N/mm2 for all mixes. These values though are low, but still fall within the minimum standard for lightweight concrete specified by[24,3] and were therefore recommended for use as lightweight concrete in masonry concrete, lean concrete bases, simple foundations for masonry work and insulating concrete.