A review on the influence of copper slag as a natural fine aggregate replacement on the mechanical properties of concrete

Abstract

Over the years, the construction industry is highly dependent on concrete for meeting the global demand of building new infrastructure. Various advancements in normal concrete have been made to make the concrete industry more efficient and developed. High strength concrete (HSC), and self-compacting concrete (SCC) are two revolutionary developments in the concrete industry that have increased the dependency of the world on concrete due to their enhanced mechanical and durability properties. However, CO2 emissions associated with cement and concrete manufacturing have created an alarming situation, and as the world is looking for sustainability and cleaner production, the pressure on the concrete industry to minimize the use of natural aggregates and cement is also increasing. Geopolymer concrete (GPC) is a type of concrete that uses various industrial wastes as a binder instead of cement and these by-products are activated by alkali. GPC is still under research and yet to be developed as a reliable product, however, the available research validates the lesser environmental impacts in GPC as compared to cement-based concrete. Other efforts have also been made to reduce the environmental impacts in concrete and substitution of natural fine aggregate (NFA) with industrial by-products is one such step that not only provides an efficient method of waste disposal but also reduces the dependency of concrete on natural resources. Copper slag (CS) is a type of nontoxic industrial waste that is obtained during matte smelting and refining of copper. CS resembles the size of NFA and can be used as partial or full replacement of NFA in various types of concrete. Various researchers have investigated the potential use of CS as NFA replacement in conventional concrete, HSC, SCC, and GPC. The current study summarizes the up-to-date trends as reported in available literature wherein CS has been used as fine aggregate in conventional concrete, HSC, SCC, and GPC. Present investigations support the use of CS as a fine aggregate in concrete. Apart from the key findings, various identified gaps, challenges, and future scope challenges have also been discussed to develop CS as a sustainable material in the construction industry.