THE FORMATION OF ETTRINGITE AT ELEVATED-TEMPERATURE

The formation of ettringite was investigated by isothermal calorimetry over the range of temperature from 50 to 70-degrees-C. Ettringite was formed using three sources of alumina: tricalcium aluminate, high alu mina cement and calcium aluminate sulfate. In accord with a diffusiona lly controlled reaction mechanism, the kinetics of ettringite formatio n exhibit minimal temperature dependence over this range. C4A3SBAR and HAC evolve comparable amounts of heat in ettringite formation while t he heat evolved when the alumina-containing reactant is C3A is signifi cantly higher.