Limestone Calcined Clay Cement as a Partial Replacement for Different Cement Types

The cement industry is a major contributor to global CO₂ emissions, highlighting the need for sustainable alternatives. Limestone Calcined Clay Cement (LC3) has gained attention for its reduced clinker content and improved mechanical properties. This study evaluates the performance of LC3 as a partial replacement for Ordinary Portland Cement (OPC) and Sulfate-Resisting Cement (SRC) in eight mix compositions with varying LC3 content. The results show that, at equivalent workability levels, replacing 30% of OPC and SRC with LC3 significantly enhanced compressive strength at both 7 and 28 days compared to the OPC control mix. The highest compressive strength reached 74 MPa in the optimal LC3 blend. However, higher replacement levels (50% and 70%) led to strength reductions. Scanning Electron Microscopy (SEM) analysis revealed a denser microstructure in the optimal LC3-based mix, confirming the strength improvements. These findings demonstrate that LC3 is a viable and sustainable alternative, offering optimal performance at 30% replacement while reducing the environmental impact of the cement industry.