Development of Optimum Aggregate Mix for High Strength Concrete with Metakaolin as Admixture

Abstract

In the development of high strength concrete, aggregate proportioning and aggregate sizes have been significant factors in the determination of strength of concrete. This has resulted in the development of mix design methods that yield the requisite aggregate size usage in the production of concrete. The particle packing model mix design which is based on continuous gradation of aggregate size is a mix design approach that is aimed at obtaining optimum aggregate mixture for varying aggregate sizes in obtaining target strength of concrete. In this study, the particle packing model mix design was implemented to produce a high strength concrete through experimental evaluations of workability and mechanical performances. Also, the influence of metakaolin on the strength and workability performances were evaluated. Concrete samples were produced using metakaolin as partial substitutes for cement in percentages of 0, 5, 10, 15 and 20. Experimental tests implemented on concrete include slump test for workability assessment, compressive strength test, splitting tensile strength test and flexural strength test for mechanical properties. Test results showed that the adopted mix design was reliable for the production of high strength concrete. The workability and mechanical performance of high strength concrete were improved by the inclusion of metakaolin into the concrete matrix. Optimum dosage of metakaolin were obtained at 15% inclusion.