Effect of Metakaoline and Recycled Fine Aggregate on Workability and Compressive Strength of Concrete

Metakaoline is a reactive alumina–silicate pozzolana produced by heating kaolinite at a specific temperature regime. In this work, the cement (OPC) was replaced partially with metakaoline by weight to determine the optimum dose of pozzolana in concrete. Concrete cubes were tested at the age of 7 and 28 days. The optimum dose of metakaoline was found to be 13% by weight of OPC. Recycled fine aggregate (crushed concrete aggregate) obtained from concrete of the demolition wastes, available locally, was used as for replacement of natural fine aggregate in concrete using the optimum dose of metakaoline in concrete mix. Natural fine aggregate in concrete was replaced with 0%, 25%, 50%, 75%, and 100% of recycled fine aggregate. The workability was found to decrease as the percentage of recycled fine aggregate was increased. Compressive strength of above mixes was determined using destructive and non-destructive tests. A Slight decrease in the compressive strength was observed as the percentage of recycled fine aggregate was increased.