Hydration Characteristics of Cementitious Composites Containing Calcium Silicate Slag Powder

A significant portion of calcium silicate slag (CSS) waste is deposited in open landfills, leading to various environmental concerns. CSS powder with high content of active β-C 2 S is a potential supplementary cementitious material. This study determined the isothermal hydration heat flows of cementitious composites containing 0 – 40% CSS powder using an isothermal calorimeter. The hydration kinetics and parameters were simulated and analyzed using Krstulovic-Dabic model. Results indicated that the first exothermic peak of the cementitious composite containing CSS powder shifted to the left and was significantly higher compared to Portland cement. The second exothermic peak also shifted to the left, but its value decreased significantly. The cumulative hydration heat of the cementitious composite gradually decreased with increasing of CSS powder content. The simulations from the kinetic model showed that the hydration rate of the entire process decreased with the increase of CSS powder incorporation. These findings are expected to provide guidance for the use of CSS powder in low-heat mortars or concrete.