Impact of oven drying and sample dimensions on calcite content in cement pastes.

In order to follow the progress of cement hydration by analytical methods, the ongoing hydration reaction needs to be stopped by removing free water from the samples. There are several water removal techniques, affecting in varying degrees the chemical composition of cement-based materials. Oven drying is one of the most widely used drying techniques because of its high effectiveness and easy availability. Nevertheless, elevated temperatures may speed up hydration processes and support carbonation. This paper aims to investigate the impact of oven drying and sample dimensions on the amount of calcite generated in the cement pastes. The cement pastes are prepared with a water-to-cement ratio of 0.4 and are stored in water for 28 days. The hydration stoppage methods applied thereafter include oven drying at 50 °C, 80 °C, and 110 °C. Their impact on the chemical composition and microstructure development, with emphasis on the calcite content in the studied cement pastes, is analyzed by means of thermal analysis (DSC/TG), X-ray diffraction analysis, and these results were complemented by mercury intrusion porosimetry. [ABSTRACT FROM AUTHOR]