Sustainable design of high strength ECC using steel slag as fine aggregate: Toward waste valorization and environmental benefits

The high cost and carbon emissions of Engineered Cementitious Composites (ECC) limit their broad application. This study explores using steel slag particles (SSP) as a sustainable substitute for silica sand in developing green, high-strength ECC. The mechanical properties and micromechanical mechanisms were evaluated at different SSP substitution ratios. Results show that SSP enhanced matrix density and reduced porosity. Macroscopically, SSP improved tensile strain-hardening behavior; the mixture with 50 % SSP achieved optimal performance, exhibiting compressive strength of 84.47 MPa, tensile strength of 8.58 MPa, and tensile strain capacity of 8.18 %. Microscopic analysis indicated that SSP strengthened the fiber/matrix interface, increasing the PSH energy index, which explains the improved ductility. Additionally, SSP replacement reduced material cost by approximately 35 % and carbon emissions by approximately 42 %, while maintaining mechanical performance. This work supports sustainable ECC development and promotes large-scale utilization of industrial solid waste in construction.