Hydration behaviour of C4AF in selected experimental conditions has been determined. C4AF has been
hydrated in the absence and presence of gypsum, two polymorphs of ye’elimite and different water/solid
ratios. C4AF in the presence of water hydrates to form mainly a hydrogarnet-type phase. The crystal structure
of C3A0.845F0.155H6 is reported from the Rietveld analysis of its synchrotron X-ray powder diffraction
pattern. The hydration of C4AF in the presence of gypsum gives AFt. However, the mixture tetracalcium
aluminoferrite/gypsum/ye’elimite gives both AFt and AFm phases. C4AF hydrated with ye’elimite in the
absence of gypsum gives only AFm. Ye’elimite has inhibited tetracalcium aluminoferrite hydration