Comparison between the Vicat test and the semi-adiabatic calorimetry to determine the set time of Portland cements

ABSTRACT The objective of this work was to compare two methods (Vicat needle and semi-adiabatic calorimeter) to determine the cement set times. Ten samples of the 2 largest used types of cement were collected in the brazil’s southern region of the same manufacturing unit during the same month. It was verified that the semiadiabatic calorimetry method is an efficient, practical and simple technique to monitor the behavior of the cement hydration process and to provide results with times varying 1.50% (4 minutes) for the CP II F-40 and 6.28% (14 minutes) for CP V ARI-RS. This difference in results may be explained by some inaccuracy during the Vicat needle methods, or the need for a greater number of replicates of both methods to work with approximate mean values. The size of the samples tested also makes it impossible to apply the curves presented in this work as behavioral pattern for the studied cements, since there is variability of composition between each batch and each manufacturer.