Effect of Cr2O3 on the formation of C3S in 3CaO :1SiO2 :xCr2O3 system

Abstract Specimens of tricalcium silicate (C3S) containing 0.5, 1, 1.5, 2, 4, and 5 wt.% Cr2O3 were prepared by repeated firing of a mix containing CaCO3 and quartz in 3:1 stoichiometric ratio along with varying concentrations of Cr2O3 at 1450°C. The final products were investigated using chemical analysis, XRD, OM, and scanning electron microscope (SEM) with EDAX. It has been found that there is a formation of CaCrO4 compound. The triclinic form of pure C3S is retained with Cr2O3 up to 2%. Introduction of 4–5% Cr2O3 converts it to the monoclinic form. Cr2O3 is soluble in C3S up to 1.56% at 1450°C. Cr2O3 improves the crystal size of C3S up to 1% only.