Harnessing iron tailings as supplementary cementitious materials in Limestone Calcined Clay Cement (LC3): An innovative approach towards sustainable construction

The increasing demand for sustainable construction materials has led to the exploration of iron tailings (ITs) as supplementary cementitious materials (SCMs) in Limestone Calcined Clay Cement (LC³). This study investigates the effects of varying ITs content in LC³ on compressive strength, microstructure, and environmental impact. Replacing 28 % of LC³ with ITs resulted in a 42 MPa compressive strength after 28 days, comparable to ordinary Portland cement (OPC), while reducing OPC content by 50 %. Microstructural analysis revealed that ITs contributed to the formation of additional C-(A)-S-H gel, enhancing the mechanical properties of the cement matrix. The findings also showed that concentrations of Zn (0.003–0.094 mg/L), Pb (0.002–0.090 mg/L), Cu (0.005–0.018 mg/L), Mn (0.115–0.712 mg/L), Ni (0.011–0.021 mg/L) in the leachates of LC³ containing ITs were below the critical limits for surface water and groundwater. Moreover, the life cycle assessment (LCA) demonstrated significant reductions in global warming potential (43.6 %), energy consumption (37.2 %), and cost (35.5 %). This study provides an innovative solution for waste utilization and environmentally friendly cement production.