Sustainable Concrete Development: Partial Replacement of Conventional Aggregates with Coconut Shells

The rising cost of conventional construction materials has necessitated the investigation of cost-effective and sustainable alternatives to traditional coarse aggregates in concrete production. This study evaluates the potential of coconut shells—an abundant agricultural waste by-product generated predominantly by oil industries—as a partial replacement for coarse aggregates in M20 grade concrete. Owing to their low biodegradability and high availability, coconut shells offer an environmentally responsible solution to reduce aggregate consumption and promote waste reutilization. Experimental analyses were carried out by substituting coarse aggregates with coconut shell particles at replacement levels of 0%, 10%, 20%, and 30%. Mechanical properties, specifically compressive and tensile strength, were evaluated at curing intervals of 7, 28, and 56 days. The results revealed that a 20% replacement yielded optimal strength performance, demonstrating mechanical properties comparable to conventional concrete. This investigation confirms that coconut shells can serve as a viable alternative material, contributing to cost efficiency, sustainable waste management, and energy conservation within the construction sector.