Hydration Water Dynamics in Tricalcium Silicate Pastes by Time-Resolved Incoherent Elastic Neutron Scattering

The translational dynamics of the hydration water in tricalcium silicate, as well as the curing kinetics of the paste, have been investigated for the first time using neutron elastic backscattering measurements. A detailed analytical model has been formulated to extract the most important features of the calcium silicate curing process. As the curing time passes, water reacts with the tricalcium silicate, forming amorphous calcium silicate hydrate and crystalline calcium hydroxide. Concurrently, the water translational dynamics slows down due to the increased confinement in the developing matrix. The time evolution of the self-diffusion constant for the hydration water shows a decrease of 1 order of magnitude after two days of curing. The presented results agree with recent molecular dynamics simulations and H-1 NMR results on similar systems.