THE EFFECTS OF PARTIAL REPLACEMENT OF CEMENT WITH RICE HUSK ASH FROM DIFFERENT LOCATIONS ON CONCRETE PROPERTIES

Abstract

This research addresses a comparative study on effects of partial replacement of cement with rice husk ash from Anaku and Omor town on concrete properties. Cement is widely noted to be one of the most expensive constituents of concrete. The entire construction industry is in search of a suitable and effective the waste product that would considerably minimize the use of cements and ultimately reduces the construction cost. This research will go a long way in reducing these agricultural waste (rice husk) which may pose great threat to the environment and also brings about reduction in weight of concrete. Ricehusk ash of both locations were prepared by open control burning, grinded and replaced with cement at 0%, 2.5%, 5% and 7.5% respectively, with a mix ratio of 1:2:4 at a constant water- cement ratio of 0.55. The compressive strength, particle size distribution and workability test of these concrete specimens were extensively studied. The compressive strength of the concrete is dependent on the curing period. The compressive strength is directly proportional to the curing period. This was observed from 7 days, 14 days, 21 days and 28 days specimens from both locations. The compressive strength of the concrete specimens decreases with an increase in the proportion of rice husk ash content for specimens from both locations; therefore the control mix (0% RHA) gave thehighest strength gain. It was concluded that at 7th day of curing Anaku concrete specimen gave early strength gain while at 28th day of curing Omor concrete specimen gave higher late strength gain. Concrete workability is inversely proportional to the percentage of rice husk ash content for all the specimens from both locations. It was concluded that Anaku concrete specimen gave higher workability compared to Omor concrete specimen.