Temperature dependence of structural build-up and its relation with hydration kinetics of cement paste

The temperature dependence of structural build-up is of great importance to some new concrete technologies, such as 3D printing and slip-form casting concrete. In this paper, the structural build-up of cement paste with various mineral admixtures, characterized by the growth of static yield stress, were measured at 10, 20 and 40 degrees C. They were related with the calorimetric curves of cement paste at various temperatures. Nucleation kinetic (K-N) and growth kinetic (K-G) were introduced to analyze the hydration dynamics. The results showed that the addition of fly ash and slag were unfavorable for the structural build-up of cement paste at 10 and 20 degrees C, however, a favorable phenomenon was observed at 40 degrees C. The additions of nano-CaCO3 or nano-SiO2 had positive effect on structural build-up at all temperatures. The incorporation of silica fume had negative effect on structural build-up at 10 degrees C. while positive effect at 20 and 40 degrees C. Both the K-N and K-G played important roles on the structural build-up rate of cement paste. K-G contributed more to the temperature dependence of structural build-up than K-N. (C) 2019 Elsevier Ltd. All rights reserved.