The effect of pressure on tricalcium silicate hydration at different temperatures and in the presence of retarding additives

Abstract The hydration of tricalcium silicate (C 3 S) is accelerated by pressure. However, the extent to which temperature and/or cement additives modify this effect is largely unknown. Time-resolved synchrotron powder diffraction has been used to study cement hydration as a function of pressure at different temperatures in the absence of additives, and at selected temperatures in the presence of retarding agents. The magnitudes of the apparent activation volumes for C 3 S hydration increased with the addition of the retarders sucrose, maltodextrin, aminotri(methylenephosphonic acid) and an AMPS copolymer. Pressure was found to retard the formation of Jaffeite relative to the degree of C 3 S hydration in high temperature experiments. For one cement slurry studied without additives, the apparent activation volume for C 3 S hydration remained close to ~ − 28 cm 3  mol − 1 over the range 25 to 60 °C. For another slurry, there were possible signs of a decrease in magnitude at the lowest temperature examined.