Effect of calcium formate on microstructure and mechanical properties of strain-hardening CaO-activated GGBFS composites

This study investigated the effects of calcium formate as an accelerator in newly developed CaO-activated strain-hardening cementless composites (SH-CASC). Six doses of calcium formate, ranging from 0 to 5 % by weight of ground granular blast furnace slag (GGBFS) and calcium oxide, were tested. Thermogravimetric analysis, mercury intrusion porosimetry, hydration heat tests, compressive tests, single fiber pullout tests, direct tensile tests, and life cycle assessment (LCA) analyses of the SH-CASC were performed. The experiment results indicated that the incorporation of calcium formate enhanced the compressive strength of SH-CASC. Furthermore, calcium formate improved the bond strength between the matrix and fiber, resulting in higher tensile strength, strain capacity, and strain energy density. SH-CASC also showed a lower environmental footprint, with reduced carbon dioxide emissions and health hazards than cement- and cementless-based strain-hardening composites. Thus, SH-CASC presents a sustainable and promising composite material in the field of construction with good mechanical properties and environmental effects.