Research on the mechanical properties of mortar utilizing carbonated steel slag

Abstract

This study evaluates the performance of cement mortar utilizing 100% carbonated electric arc furnace (EAF) steel slag substitute for sand. Raw slag underwent aqueous carbonation, achieving a 2% CO₂ uptake by transfer CaO into CaCO₃, verified via XRD and TGA. Three formulations, a reference, untreated slag (100SS), and carbonated slag (100SS-C), were assessed for mechanical and volumetric properties. While 100SS reduced baseline strengths compared to the control, carbonation mitigated these deficits. Specifically, the 100SS-C mixture demonstrated a 4.27% increase in flexural strength and enhanced compressive performance relative to 100SS. Furthermore, precipitated CaCO₃ densified the microstructural matrix and obstructed capillary pores, significantly reducing drying shrinkage. These findings confirm viability of carbonated EAF slag in mortar, presenting approach to waste valorization, resource conservation, and carbon sequestration.