EFFECT OF METAKAOLIN ON STRENGTH AND DURABILITY OF CONCRETE

The aim of this investigation is to study the performance of concrete containing different percentages of local metakaolin and to identify the optimum addition percentage and to compare the performance of metakaolin with other pozzolanic materials as silica fume . The study focuses on the strength and durability of concrete of the blended concrete containing different percentages of metakaolin for two types. The concrete mixture with the percentages of 5%, 10%, and 15% by weight of cement in the first type used W/C = 0.55. Concrete Cubes are tested at the age of 3, 7, 14, 28, and 60 days. The results showed that the strength development of concrete blended with Metakaolin is enhanced. It was found that 5% of Metakaolin appears to be the optimum, where concrete exhibits enhanced compressive and tensile strength at all ages compared to reference samples. The second Type concrete mixture used superplasticizer to reduce water/cement ratio (W/C=0.4) to keep the same slump (75-120mm). The concrete mixture with the percentages of 5% and 10% by weight of cement is prepared. Concrete sample are tested at the age of 7, 14, 28, 60, and 90 days. In addition to both absorption and permeability test at 28 days. The result showed that the strength development of concrete blended with metakaolin is enhanced. Also, it was found that 5% appears to be the optimum. Where metakaolin concrete 5% exhibits enhanced compressive and tensile strength at all ages compared to reference samples. When compared the results of silica fume and metakaolin appear to be an effective pozzolan in enhancing concrete strength. From the study, it is clear that metakaolin is a very reactive pozzolan and results in enhanced strength and some improvement in Durability.