In Situ Quasi-elastic Neutron Scattering Study of the Hydration of Tricalcium Silicate

We report on the novel application of quasi-elastic neutron spectroscopy to study the reaction mechanism between tricalcium silicate and water. The in situ data taken at a series of fixed temperatures varying from 10 to 40 °C show that the amount of free water in the system remains relatively constant for an initial period, ranging from 1 h at 40 °C to 16 h at 10 °C. This is followed by an exponential decrease in the amount of free water that crosses over to a diffusion-limited behavior for later times. Fits to an Avrami type behavior allow us to determine an activation energy for the hydration process on the order of 30 kJ/mol.