Hydration and Crystallization Pressure of Sodium Sulfate: a Critical Review

Abstract

ABSTRACTThe two most frequently mentioned mechanisms used to explain the severe damage that occurs when a porous material, containing the anhydride phase of sodium sulfate, is exposed to either water or rising humidity are critically reviewed. Both derivations are presented along with their underlying hypotheses. Critical differences are discussed and it is concluded that crystallization pressure is the relevant mechanism. In effect however, it is shown that the expressions obtained both for crystallization pressure and hydration pressure are quite similar.