Effects of Constituents of Concrete Locally Sourced in Kakamega County and their Effect on the Compressive Strength

Abstract

This paper presents the findings of a research on the characteristics of the various locally sourced materials used in concrete production within Kakamega County and their effect on its compressive strength. The research sampled fine aggregates from quarries, rivers and roadside, coarse aggregates from a machine crusher and hand crusher and threePortland Pozzolana Cement and one Ordinary Portland Cement used as a control. They were subjected to characterization tests. The results showed that fine aggregates vary in their characteristics due to their different sources with silt contents values of 5%,12,82% and 33.33%, specific gravity for coarse aggregate was 2.02 and 2.28 while the cement brands had similar characteristics. Concrete mix design was done.1008 concrete cubes were cast and cured as compressive strength tests were conducted. The results showed that varying characteristics of aggregates affects the mix ratios. The results showed that PPC combined with machine crushed coarse aggregate and quarried fines or river sand can be used to produce concrete class C20/25: higher concrete classesare not feasible with PPC. It is therefore important to characterize constituents of concrete to determine theireffecton the compressive strength of concrete.