The Influence of Metakaolin on the Engineering Properties of Self-Compacting Concrete.

Abstract

This research studied the effects of Metakaolin pozzolan on the engineering properties of self-compacting concrete (SCC) in which Complast sp40 was used as a superplasticizer. Laboratory tests were conducted on the Metakaolin and the aggregates to determine their properties. Different fine aggregate / coarse aggregate (FA/CA) mix proportions for SCC with a target strength of 35 N/mm² were used to produce concrete cube specimens of sizes 150mm x 150mm x 150mm by mixing the aggregates, water, complast sp40 and partially replacing cement with 0%, 5%, 10%, and 15% metakaolin. The fresh concrete for each batch was tested for workability using slump test. The concrete cubes prepared were cured in water for 28, 60 and 90 days, after which the density and the compressive strength of the hardened concrete were determined. The slump test results showed a decrease in the workability of fresh concrete as the percentage Metakaolin increases. The results showed a reduction in the density of concrete as Metakaolin content in concrete increases. It was observed from the results that the compressive strength of the concrete increases as the curing age increased from 28 to 90 days. Aggregate proportioning significantly impacted strength, with optimal fine aggregate to coarse aggregate (FA/CA) ratios of 0.45/0.55 yielding the highest strength for all curing ages. 10% Metakaolin replacement level exhibited the highest strength compared to 5% and 15% replacement levels.