Abstract

The growing emphasis on sustainable construction has encouraged the use of industrial and biodegradable wastes as supplementary cementitious materials. This study examines the feasibility of utilizing waste eggshell powder (ESP) as a partial replacement for cement in M35-grade concrete. Cement was substituted with ESP at proportions of 0%, 2%, 4%, 6.5%, 8%, and 10% by weight. Workability was assessed using slump tests, while mechanical performance was evaluated through compressive and split tensile strength tests at 7, 14, and 28 days. Results indicated that ESP incorporation improved both workability and strength up to a replacement level of 4%, achieving a maximum compressive strength of 45.8 MPa—representing a 26.6% improvement over the control mix. Higher replacement percentages led to gradual strength reduction due to cement dilution effects. The findings highlight ESP’s potential as a low-cost, eco-friendly cement substitute, contributing to reduced cement consumption, waste valorization, and lower CO₂ emissions.