Beyond waste: performance insights into non-ferrous slag-based cementitious composites—a review

Abstract The valorization of non-ferrous slags as cementitious materials and aggregates represents a promising pathway for sustainable construction. Generated during the extraction and refining of metals such as copper, lead, zinc, and nickel, these industrial by-products are increasingly studied as alternatives to conventional binders and aggregates. This review synthesizes advances in understanding the physical, chemical, and mineralogical characteristics of non-ferrous slags and their influence on the fresh, mechanical, and durability properties of cement and concrete composites. Reported benefits include improvements in compressive and tensile strength, enhanced density, and potential durability gains, alongside clear economic and environmental advantages such as reduced raw material demand, waste minimization, and lower carbon footprint. However, challenges remain regarding workability, setting behavior, and long-term performance, particularly under variable production conditions and in the presence of toxic elements. Future research directions are outlined, emphasizing optimized processing, activation strategies, and life-cycle assessments to enable the safe and large-scale integration of non-ferrous slags into sustainable cement and concrete technologies.