Sustainable Concrete with Recycled Glass and Oyster Shell as Partial Cement Replacements: A Study on Performance Environmental Impact

The current and significant environmental pollution caused by the use of cement in structural construction highlights the need for more sustainable alternatives. This research evaluates the use of uncalcined scallop shell powder (SP) and recycled glass powder (GP) as partial replacements for cement in conventional concrete mixes with a design strength of f'c = 280 kg/cm². SP and GP were incorporated in a 2:1 ratio at the following replacement levels: 2.5% SP + 5% GP and 5% SP + 10% GP. The analysis conducted on the concrete includes CO₂ emissions associated with its production, workability in its fresh state, and compressive strength in its hardened state. As a result, the mix with the lower replacement percentage proved to be the most optimal, achieving a 1-inch increase in workability and a 2.49% increase in 28-day compressive strength compared to the control mix, along with a 1.08% reduction in CO₂ emissions. This demonstrates the structural and environmental viability of concrete incorporating SP and GP.