The role of water in acid-base cements

Water has three possible roles in acid-base cements. First, it acts as the medium for the setting reaction of these materials, and second, it is one of the components of the set cement, actually becoming incorporated into the cement as it hardens. Third, water may act as plasticizer in these cements. All of these roles are reviewed here. 

Water as the solvent is essential for the acid-base setting reaction to occur. Indeed, as was shown in Chapter 2, our very understanding of the terms acid and base at least as established by the Bronsted-Lowry definition, requires that water be the medium of reaction. Water is needed so that the acids may dissociate, in principle to yield protons, thereby enabling the property of acidity to be manifested. The polarity of water enables the various metal ions to enter the liquid phase and thus react. The solubility and extent of hydration of the various species change as the reaction proceeds, and these changes contribute to the setting of the cement. 

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