Cement Calorimetry With Different Condition Of Calcium Sulfate And Water Reducer Admixture

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 process can be monitored by calorimetric techniques which permits to evaluate from the time that cement comes into contact with water, the paste behavior through the release rate of heat produced by the interpretation of acceleration or delay of hydration reactions as well as the intensity of the heat release occurring.In this paper the influence of water-reducing admixtures in cement with low C(3)A content, which was previously heated to remove partially and totally the combination water of calcium sulfate, are evaluated. Through a calorimeter, hydration development under isothermal conditions (20 and 30 degrees C) was studied. Results show that in general increasing the dose of admixtures the hydration reactions are delayed, and on the other hand because of the prior heating of cement significant changes are produced in the acceleration of these reactions. With increasing temperature, the hydration reactions occur earlier with higher intensity peaks.