A molecular dynamic study of cementitious calcium silicate hydrate (C-S-H) gels

In this article, we study the polymerization of silicic acids (Si(OH) ₄) in the presence of calcium ions by molecular dynamics simulations. We focus on the formation and structure of cementitious calcium silicate hydrate (C-S-H) gels. Our simulations confirm that, in accordance with experiments, a larger content of calcium ions slows down the polymerization of the cementitious silicate chains and prevents them from forming rings and three-dimensional structures. Furthermore, by an analysis of the connectivity of our simulated silicate chains and by a count of the number of Ca-OH and Si-OH bonds formed, the relationship with commonly used structural models of C-S-H gels, such as 1.4 nm tobermorite and jennite, is discussed.