Engineered cementitious composites (ECC) with limestone calcined clay cement (LC3) and desert sand: Mechanical properties, microstructures and carbon footprint

This study innovatively proposes the synergistic application of limestone calcined clay cement (LC3) and desert sand in engineered cementitious composites (ECC), achieving dual breakthroughs in material performance and environmental benefits. Compared to existing research, its core contribution lies in revealing the unique synergistic mechanism between LC3and desert sand: The active components in desert sand undergo in-situ reactions with metakaolin in the LC3 system, significantly optimizing the interfacial transition zone (ITZ) structure while simultaneously enhancing fiber-matrix interfacial bonding strength. This mechanism resolves the inherent contradiction between ductility improvement and crack control in conventional ECC materials. The synergistic effect enables the novel LC3 -DS-ECC to achieve 40 % higher ultimate tensile strain capacity compared to regular ECC, with crack quantity increasing from 42 to 110 microcracks, substantially improving tensile toughness and crack control capability. Furthermore, through synergistic optimization of pore structure, the composite material demonstrates 28 % reduction in carbon emissions and 20.5 % decrease in energy consumption while simultaneously enhancing impermeability and durability. This breakthrough provides an innovative pathway to address the high energy consumption and emission challenges inherent in traditional high-ductility materials.