Synergistic effect of hydration and carbonation of ladle furnace aslag 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 and different LFS particle sizes, determining the effect of these varying conditions on the microstructure and formation mechanism of cementitious substances. The results show that in the early stages, C2S and C3S undergo hydration to generate C–S–H gel, which then undergoes decalcification and condensation to generate CaCO3 and Ca-deficient C–S–H gel; the hydration reaction and carbonation reaction promote and influence each other. The increase in temperature was found to hinder the formation of CaCO3 from Ca2+ and CO32−, thus reducing the efficiency of hydration carbonation. The increase in particle size was not conducive to the leaching of C2S and C3S to the surface of the reaction phase, which in turn reduced the degree of decalcification and polymerization of the C–S–H gel in the carbonation phase. It was concluded that the optimum LFS hydration and carbonation reactions were achieved at 20 °C and with a LFS particle sizes < 38 μm.