Physico-mechanical properties of eggshell powdered-reinforced laterite composites for sustainable construction

Abstract The environmental impact of cement production, contributing approximately 7% of global CO₂ emissions, underscores the urgent need for sustainable alternatives in construction. One promising solution is the use of agricultural waste, such as eggshell powder (ESP), which is rich in calcium carbonate and commonly discarded. This study investigates the potential of ESP as a partial cement substitute in laterite bricks, addressing both waste management and sustainable material development. The objective was to assess the effects of incorporating 0–25 wt% ESP into bricks with a fixed laterite-to-cement ratio of 80:20. The bricks were evaluated for compressive strength, flexural strength, density, water absorption, and surface hardness. Results revealed that 15% ESP yielded optimal performance: compressive strength reached 2.56 MPa (a 29.9% increase over the control at 1.97 MPa), flexural strength improved to 1.03 MPa (from 0.87 MPa), and hardness peaked at 54.6 HB. Density slightly decreased from 1.676 to 1.478 g/cm³, while water absorption initially dropped but rose beyond 10% ESP. The improvements at 15% ESP are attributed to the filler effect and potential pozzolanic reactions, which enhance matrix densification. Beyond this level, excessive ESP reduced cohesion, increasing void content and weakening performance. In conclusion, ESP can effectively replace up to 15% of cement in laterite bricks, improving strength and sustainability. Future studies should investigate the microstructural behavior, durability under real-world conditions, and optimized curing methods to validate long-term applicability.