No abstract

Ordinary TGA and high-resolution TGA tests were carried out on three different Portland cements to study the phases present during the first day of hydration. Tests were run at 1, 6, 12, and 24 hours of hydration, in order to determine the phases at these ages. High-resolution TGA tests were used to separate decompositions presented in the 100-200 °C interval. The non-evaporable water determined by TGA was used to determine hydration degree for the different ages. The effect of particle size distribution (PSD) on mineralogical evolution was established, as well as the addition of calcite as mineralogical filler. Finer PSD and calcite addition accelerates the hydration process, increasing the hydration degree on the first day of reaction between water and cement. According to high-resolution TGA results it was demonstrated that ettringite was the only decomposed phase in the 100-200 °C interval during the first 6 hours of hydration for all studied cements. C-S-H phase starts to appear in all cements after 12 hours of hydration.