Effect of Metakaolin on Physical and Mechanical Properties of Concrete

In recent years, the application of supplementary cementitious materials has gained significant attention in the development of high-performance concrete. Replacing a portion of cement with mineral admixtures not only reduces environmental impacts associated with cement production but also enhances the durability and service life of concrete structures by improving their overall performance compared to conventional concrete. The present study experimentally investigates the use of metakaolin as a partial substitute for cement to evaluate its influence on concrete behavior. Fresh concrete was assessed through slump tests, while hardened concrete properties, including compressive strength, split tensile strength, and flexural strength, were evaluated up to 28 days of curing. Metakaolin was incorporated at replacement levels of 4%, 8%, 12%, 16%, and 20% by weight of cement, using a constant water–cement ratio of 0.43. Based on the experimental results, the mixture containing 12% metakaolin was identified as the optimum blend, demonstrating superior performance. The scope of this research focuses on assessing the effect of partial cement replacement with metakaolin on the fresh and hardened properties of M35 grade concrete. Key parameters such as workability and strength characteristics were studied at various curing ages to establish the effectiveness of metakaolin as a sustainable cementitious material.