Hydration of the silica fume-Portland cement binary system at lower temperature

In order to explore the hydration structure of the silica fume-Portland cement binary system at lower temperature, strengths of the cement mortars were measured at −10 °C, −5 °C, 0 °C and 5 °C, content of Ca(OH)2 was quantified using thermogravimetry-differential scanning calorimetry (TG-DSC) method, and thermal analysis, scanning electron microscope (SEM) method and mercury porosimetry were employed for the microscopic mechanism analysis. The results indicated that, silica fume could contribute to the improvement of the hydration structure of the binary system. The results showed that strengths of the binary system decreased apparently, content of Ca(OH)2 reduced, total heat of the hydration decreased significantly, the total porosity increased and the compactness of the structure decreased at the lower temperature. The lower temperature hindered the hydration evolution of the binary system and inhibited the pozzolanic activity of silica fume.