Polymorph transformation kinetics of Ca₃SiO₅ with MgO

Tricalcium silicate (Ca₃SiO₅ (C₃S)) is the primary cement phase in Portland cement. An understanding of its transformation kinetics is important to make use of its polymorphism. In this study, X-ray diffractometry and Rietveld refinement were used to qualitatively and quantitatively analyze the phase compositions of C₃S with 2.0% MgO. The results show that C₃S with 2.0% MgO is a monoclinic polymorph, M3. Heat treatment changes this monoclinic polymorph to a triclinic polymorph via the precipitation of MgO. The transformation kinetics follows the first-order exponential decay function.