Application of high-temperature rapid catalytic technology to forecast the volumetric stability behavior of containing steel slag mixtures

• High-temperature rapid catalytic technology can forecast expansion in a short time.
• Rapid catalytic technology can forecast steel slag instability in a short time.
• The degradation rate of DSS with a high f-CaO content was greater than that for BOF.
• Steel slag critical value for the substitute amount was 20–30%.
• Rapid catalytic technology can forecast the results of autoclave expansion.

Steel slag from the steel and iron industries often exhibits volumetric instability (expansion) due to long-term usage. Therefore, this study applied a high-temperature rapid catalytic technology to accelerate the hydration reaction to forecast the volumetric instability of steel slag in the shortest time. The steel slag included basic oxygen furnace (BOF) slag and desulfurization slag (DSS), which replaced 50% of natural river sand by weight for 1 to 4 days of high-temperature catalysis (100 °C) and autoclave expansion. In order to forecast more accurate results, a numerical regression was applied to crosscheck the test result and simulate a theoretical expansion value. The results showed that the specimens of each group ruptured after a minimum of three days of high-temperature catalysis when the substitution amount was 30%. The expansion rupture warning value was within approximately 0.13–0.14%. The correlation coefficient R2, obtained using a simulated expansion value, was greater than 0.9. The degradation rate of DSS with a high free lime (f-CaO) content was greater than that for BOF.