Prior to XRD, TGA and NMR analysis, the samples were placed in a plastic container in a thermal bath set at 20 °C. At the desired ages, the hydration was stopped following the protocol given by Palacios et al. : crushing with a hammer, washing twice with ultrapure water and then with isopropanol. Finally, the samples were dried in a vacuum desiccator at room temperature and finely ground in a mortar.