The Substitution Effect of the Fine Aggregate in Concrete with Oyster Shell

The construction industry contributes significantly to global carbon emissions, accounting for approximately 27% of total emissions. With the increasing demand for concrete, there is a growing need to explore alternative materials that can reduce environmental impact. This study investigates the potential of using oyster shell powder, a waste material, as a partial replacement for fine aggregates in concrete. The methodology involves replacing fine aggregates with oyster shell powder in varying proportions (0%, 10%, 20%, 30%, and 40%) and testing the compressive strength of the resulting concrete after 56 days. The concrete mix used in this study consists of 16.67% cement, 33.33% fine aggregates, and 50% coarse aggregates (10-20 mm). The findings show that increasing oyster shell content reduces the concrete's compressive strength; however, at 40% replacement, the concrete still achieves a compressive strength of 30 MPa, which meets the required building strength standards. Additionally, the use of oyster shell powder reduces the unit weight of concrete by approximately 10% at the 40% substitution rate, due to the lower specific gravity of oyster shells compared to sand. This research highlights the potential of using oyster shell powder as a viable solution for mitigating oyster shell waste while providing an alternative material for fine aggregates in concrete.