Assessing setting times of cementitious materials using semi-adiabatic calorimetry

The most common methods for the determination of setting times of cements are the various penetration tests. One of the most important of these is the Vicat method, which is the current standard measurement (EN 196-3) to determine the setting time of cement. However, there are alternative methods that can be used to monitor the setting process and eliminate several issues that arise from the Vicat method, such as intermittent measurement, measurability of cement pastes of non-standard consistency, testing mortars and concretes.

One such method is semi-adiabatic calorimetry (SAC), which can be an alternative to penetration tests in appropriate circumstances. In this study, determination of setting times of two sources of CEM I 42.5 N cement was observed, using semi-adiabatic calorimetry at different (0.25; 0.27; 0.29; and, 0.31) water to cement ratios (w/c). During our measurements, we observed that the ratio between the setting time of a given source of cement and the time it took to reach the maximum rate of heat development was almost constant for the same cement and w/c ratio, which enables a simple and inexpensive routine measurement of setting times of Portland cement.