LAUSR

Abstract In this work we studied two samples of triclinic C3S. Namely pure triclinic C3S with no addition of foreign ions and triclinic C3S doped with 0.5 wt.-% Al2O3 to investigate the influence of aluminium on the hydration of C3S in the first 24 h and additionally the effect of KOH solution. During hydration Al-doped C3S shows lower reaction rates in the acceleration period compared to pure C3S. Al ions lead to precipitation of C-A-S-H phase and reduces the overall reactive surface area of C-S-H. Furthermore, Al ions in solution decrease the supersaturation of C-S-H during hydration and therefore the precipitation rates are lower for the Al-doped C3S. The addition of KOH solution leads to a general acceleration of reaction for both C3S samples, but at a concentration of 0.3 mol/L KOH both samples show comparable reaction rates during the main hydration event and the effect of Al is reversed.