Properties of Sustainable High Strength Concrete with Waste Copper Slag

The present work investigates copper slag as a substitute for river sand in high-strength concrete. The concrete mixtures were manufactured with 10%, 30%, 50%, 70%, and 100% of copper slag to evaluate the mechanical and durability properties. The experimental results indicate that replacing copper slag above 50% affects the performance characteristics of the concrete due to its high angularity and lower water absorption characteristics. The strength of concrete with 50% copper slag is improved by 5.6%, whereas the strength of concrete with 100% copper slag is reduced by 2.75% at 28 days. However, increased curing to 90 days improves the strength of the former by 7.16% and reduces the latter by only 0.23%. The water absorption, porosity, and rapid chloride penetration of the concrete mixtures with 100% copper slag are increased by 10.44%, 13.20%, and 19.56% compared to control concrete. Micro-structural investigations through SEM infer higher replacement of copper results in higher void formation due to its reduced water absorption.