Performance Assessment of High-Strength Concrete Incorporating Copper Slag as Fine Aggregate

The increasing demand for natural sand in concrete production has resulted in scarcity and environmental issues, driving the need for sustainable alternatives. Copper slag, an industrial by-product of the copper smelting process, offers potential as a replacement for fine aggregate in high-strength concrete. This study investigates the performance of M60 grade concrete with copper slag as a partial and full replacement for natural sand at levels of 0%, 20%, 40%, 60%, 80%, and 100%. Fresh properties were evaluated through slump cone tests, while hardened concrete properties were assessed using compressive strength tests at 7, 14, and 28 days, as well as split tensile and flexural strength tests at 28 days. Results indicate that workability increased with higher copper slag content due to its smooth surface texture and low water absorption. Compressive strength achieved maximum performance at 40% replacement, with notable improvements compared to the control mix. However, beyond 60% replacement, a decline in strength was observed due to excess free water and weaker interfacial bonding. Split tensile and flexural strengths showed similar trends, with optimum values observed at 40–60% replacement levels. The findings suggest that copper slag can replace up to 60% of natural sand in M60 concrete without compromising structural performance, thereby contributing to sustainable construction practices and effective waste management.