Reactivities of Various Silicates with Calcium Hydroxide and Water

The reactivity of oxides and silicates with alkaline solutions is especially important in cement chemistry and is closely related to the pozzolanic reaction, the alkali‐aggregate reaction, and to glass fiber reinforcement of hardened cement. Thus, the rate of the hydration reaction between several silicates and Ca(OH) 2 or portland cement at 20° and 80°C was studied. Results showed that essentially high reactivity in the reaction with Ca(OH) 2 was found in Italian pozzolan, metakaolin, and silica gel in which the first two have very high Blaine surface areas. The pozzolanic reaction of typical oxides and silicates was considered from a thermodynamic point of view.