Superplasticizers for Ciment Fondu. Part 2: Effects of temperature on the hydration reactions

In an investigation of the use of super plasticizers with Ciment Fondu, it was expected that they would have a profound influence on the interactions between temperature, setting time and hydration kinetics. The behaviour of Ciment Fondu in the absence of admixtures has been investigated using conduction calorimetry, supported by setting time measurements. The results confirm that hydration is retarded to the greatest extent at around 30°C, above which progressive acceleration occurs. Applying the Avrami—Erofe'ev equation showed that the maximum rate of heat evolution and the time at which it occurs are reliable kinetic parameters to quantify the hydration rate. In the range 30-45°C the activation energy for hydration is 120 kJ/mol.