Paste models for hydrating calcium sulfates, using the approach by Powers and Brownyard

In the present paper paste models are presented for pastes consisting of calcium sulfates anhydrite ( C S ¯ ) and hemihydrate ( C S ¯ H 0.5 ) that hydrate to the hydration product dihydrate/gypsum ( C S ¯ H 2 ) . A similar approach is followed as used for hydrating cement by Powers and Brownyard [19]. Closed-form equations are derived for the volume fraction of the unreacted binder (the considered calcium sulfate), unreacted water, chemical shrinkage and hydration product (gypsum). The derived equations, governing the paste composition, depend on the composition of the binder and of the water-binder ratio, and of the degree of hydration. The equations are in good agreement with information from literature, empirical and theoretical.