Abstract
Gypsum has the property to lose ¾ of water molecules, during calcination, turning into hemihydrate (gypsum) which, in contact with water, rehydrates up recovering the original form of the dihydrate. The plaster in contact with the water passes through stages of dissolution, nucleation, and recrystallization. After a certain time (setting time) the paste hardens and gains strength. The phy…