Synergistic effect of hydration and carbonation of ladle furnace slag on cementitious substances

Abstract Ladle furnace slag (LFS) can undergo hydration and carbonation reactions as cement. This article explores the effect of LFS hydration and carbonation reactions on cementitious substances at different temperatures or different particle sizes, as well as the microstructure and formation mechanism of the cementitious substances. The results show that C2S and C3S undergo hydration reaction to generate C-S-H gel in the early stages, which then undergoes decalcification and condensation to generate CaCO3 and Ca-deficient C-S-H gel. The increase in temperature hinders the formation of CaCO3 from Ca2+ and CO32-, thus reducing the efficiency of hydration carbonation. The increase in particle size is not conducive to leaching of C2S and C3S to the surface of the reaction phase, which in turn reduces the degree of decalcification and polymerization of C-S-H gel in the carbonation phase. It were concluded that the best hydration and carbonation reactions of LFS were achieved at 20 °C and particle sizes < 38 μm.