Optimization of Recycled Coarse Aggregate Replacement Ratio in Structural Concrete

This research evaluates the use of recycled coarse aggregates (RCA) as a partial replacement for natural coarse aggregates in M20 grade concrete, focusing on compressive strength performance at 7 and 28 days. Concrete mixes were prepared with 0%, 25%, and 50% RCA replacement, and results showed a gradual decrease in strength with increasing RCA content due to higher porosity and weaker bonding caused by adhered mortar. However, concrete with 25% replacement exhibited strength comparable to conventional concrete, while 50% replacement showed acceptable performance for structural use. The findings indicate that RCA can be effectively utilized up to 50% replacement without significant loss in compressive strength, supporting sustainable construction practices.