The precipitation of the hydrate phases during hydration was followed by in-situ XRD. Diffractograms were recorded by using a Bruker D8 Advance diffractometer equipped with a Cu-source and a VÅNTEC-1 detector (12 • 2θ detector opening). The diffractometer optics consisted of a divergence slit with 0.2 • and primary and secondary soller slits of 2.5 • .