The synthesis of tricalcium silicate (C 3 S) was conducted according to a modified synthesis protocol of Li et al. . Analytical grade CaCO 3 and fused silica (Amosil 510, HPF Minerals) were mixed at a molar ratio of Ca/Si = 3 and homogenized with water (water to solid ratio, w/s = 2) in a ball mill (AAM-WA 350, AAM Mahltechnik, Germany, 24 h, 70 rpm, 12.5 mm ZrO 2 balls). The white paste was filled into four circular silicone molds, left to dry for two days, unmoulded, and dried to constant weight at 120 • C. The obtained cylinders were transferred to platinum crucibles and sintered at 1550 • C for 10 h. The reaction product of the solid-state reaction was quenched at 1500 • C using pressurized air.