Cement Calorimetry with Different Conditions of Calcium Sulfate and Water Reducers Admixtures

HORACIO DONZA; VIVIANA RAHHAL

Johanesburgo

Congreso; International Conference on Construction Materials and Structures; 2014

S.O. Ekolu et al.

Abstract.  Heat development during portland cement hydration is affected by the type of cement used, by the presence of additions and admixtures, by "water /binder material" ratio, by the calcium sulfate state, and others.  Hydration processcan be monitored by calorimetric techniques which permits to evaluate from thetime that cement comes into contact with water, the paste behavior through therelease rate of heat produced by the interpretation of acceleration or delay ofhydration reactions as well as the intensity of the heat release occurring. In this paper the influence of water-reducing admixtures in cement with lowCA content, which was previously heated to remove partially and totally thecombination water of calcium sulfate, are evaluated. Through a calorimeter,hydration development under isothermal conditions (20 and 30 °C) was studied. Results show that in general increasing the dose of admixtures the hydrationreactions are delayed, and on the other hand because of the prior heating of cementsignificant changes are produced in the acceleration of these reactions. Withincreasing temperature, the hydration reactions occur earlier with higher intensitypeaks. 3