Abstract Calcium aluminate cement reactions with water result in anhydrous phases dissolution, followed by nucleation and crystal growth of hydrate compounds. Due to the dynamic characteristics of this process and in order to evaluate the phase transformation kinetics of such materials, suitable methods to halt hydration are required. In this work, the use of acetone and microwave drying, aiming to withdraw free water and inhibit further reactions, was evaluated. X ray diffraction was used to quantify the phases generated in the cement samples kept at 37 °C for 1–15 days. The advantages and drawbacks of these procedures are presented and discussed. Using microwaves to halt the hydration process in shaped samples seems to be effective to withdraw the cement free water, if a previous grinding of the material is carried out. The procedure suggested can be used in researches in the refractory castable area, endodontic cements and others.