Impact of Nano-Calcium Carbonate on Thermokinetics in the Hydration of Portland Cement

This study systematically examines the effects of nano-calcium carbonate (nano-CaCO3) on the heat release characteristics, mechanical properties, microstructure, and reaction mechanism of cement hydration through hydration heat tests, compressive strength tests, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermokinetic modeling. With nano-CaCO3, the hydration heat peaks have an earlier onset, heat is released at a higher rate and a greater amount, and the early strength is increased. According to SEM analysis, nano-CaCO3 improves the cement microstructure. The Krstulovic–Dabic model confirms that nano-CaCO3 accelerates the hydration of Portland cement by promoting the nucleation and growth of hydration products and reducing the diffusion resistance.