Temperature-driven synergistic hydration in LS-BOFS binders: From phase evolution to temperature adaptability

The alumina-deficient mineralogy of basic oxygen furnace slag (BOFS) limits its hydration. This study introduces alumina-rich ladle furnace slag (LS) to trigger β-C 2 S–C 4 AF synergy, with a standardized 2 wt% gypsum dosage added to regulate setting kinetics. The impact of temperature (5–35 °C) on this LS-BOFS-gypsum system was investigated. Results show plain BOFS remains nearly inert at 5–15 °C, while the binary system demonstrates robust “temperature adaptability” via persistent synergy. At 35 °C, quantitative analysis reveals accelerated phase transformation into Si(Fe)-katoite and C-(A)-S-H, reducing macropores (>100 nm) by 42.5% and yielding a 7–10 fold strength increase over the control. Furthermore, heavy metal leaching tests confirm the effective immobilization of Cr and V within the refined matrix. This work clarifies the temperature-driven mechanisms of LS-BOFS binders, supporting their resilient application in diverse climates.