A sweet answer to how sucrose delays tricalcium silicate hydration
Weiqing Xu, Deni Mance, Jean-Baptiste d’Espinose de Lacaillerie, Robert J. Flatt
Abstract
The way in which chemical admixtures delay cement hydration is a highly debated topic in the cement related literature. Sugars in particular can cause substantial retardation and have been investigated by many researchers, but with conflicting conclusions. In this paper, synthetic tricalcium silicate is used as a model for cementitious systems and sucrose is chosen as an example of a chemical admixture, due to its strong ability in delaying hydration. A methodology combining careful temperature-controlled adsorption, specific surface area, and isothermal calorimetry measurements is presented. Results show that the average hydration velocity in the induction period is proportional to the fraction of the tricalcium silicate surface not covered by sucrose. This suggests a dissolution control of hydration during the induction period – dissolution being strongly inhibited by adsorbed sucrose.