Abstract:
Supplementary cementitious materials are crucial to reduce costs and carbon footprint, as traditional cement production emits greenhouse gases. This study explores using copper tailings and marble dust as substitutes for Ordinary Portland Cement (OPC) in concrete. In this investigation, three concrete mixes were designed, and tests were carried out to compare their tensile and compressive strengths. C0M0 served as the control mix, i.e., mix with no replacement of OPC. While in C5M5 mix, 10% OPC was replaced by 5% copper tailings and 5% marble dust. While in mix C5M10, 15% OPC was replaced by 5% copper tailing and 10% marble dust. Experimental observation was that the control mix (C0M0) exhibited highest compressive strength, which then declined for C5M5 mix and further retreated in increasing path in C5M10 mix, with almost reaching compressive strength of the C0M0 (control) mix. The compressive strength as compared to the control mix was reduced by about 24.8% for C5M5 mix and close to 0.9% for C5M10 mix. The observed decrease in strength was attributed to the moisture-absorbing nature of copper tailings and marble dust, which limited water availability for OPC hydration, while marble dust's filler action contributed to strength gain. Ultrasonic Pulse Velocity (UPV) tests established a relationship between compressive strength and sound velocity. Economic analysis revealed the cost-effectiveness of concrete incorporating copper tailings and marble dust. The study highlights the potential for developing concrete strength with these waste materials, promoting environmentally friendly and cost-effective construction practices.