Dehydration kinetics of Portland cement paste at high temperature

Portland cement paste is a multiphase compound mainly consisting of calcium-silicate-hydrate (CSH) gel, calcium hydroxide (CH) crystal, and unhydrated cement core. When cement paste is exposed to high temperature, the dehydration of cement paste leads to not only the decline in strength, but also the increased pore pressure in the paste. In this article, the dehydration kinetic was characterized in term of the combination of kinetics of CSH and CH. The dehydration kinetics data of cement paste at different heating rates was collected by thermogravimetry. The influence of temperature on the reaction rate is analyzed by Arrhenius equation. The Arrhenius parameters of CSH and CH, activation energy, and pre-exponential factor are determined by isoconversional method. The calculated kinetics parameters were validated by further experimental data finally.