Direct compressive strength and Elastic modulus of recycled aggregate concrete

An experimental investigation was conducted to study the change in direct compressive strength and elastic modulus of recycled aggregate concrete in presence of fly ash (as replacement of cement). Concrete cubes, cylinder and prisms were prepared as test specimens with varying percentage of fly ash using natural aggregate and recycled aggregate. These specimens were tested at different age of concrete to have compressive strength, elastic modulus, split tensile strength as well as flexural strength and their changes were noticed. MIP (Mercury intrusion porosimetry) test was conducted to estimate the percentage of micro voids in recycled aggregate concrete and also to appreciate the change of these micro voids due to presence of fly ash.Empirical formulas involving major parameters such as fly ash content, water cement ratio, age of concrete etc., have been developed to predict elastic modulus and compressive strength of recycled aggregate concrete.