Tricalcium silicate modeling and numerical simulations
Résumé
In order to identify and quantify what is modified when tricalcium silicate hydration rate varies, we have developed a model to simulate experimental evolution of reaction advancement versus time. It is experimentally observed that the hydrates formation consists of a primary heterogeneous C-S-H nucleation leading to the formation of clusters followed by the anisotropic growth of these clusters. In our model, C-S-H nucleation is described by a random distribution of clusters on a surface. We split the growth step into two processes corresponding to the clusters growth on the surface (parallel growth) and the increase of the cluster thickness (perpendicular growth). Each process is characterized by a distinct growth rate. The parameters of the model are those which can be varied experimentally: the initial surface of anhydrous particles, the number of initial C-S-H clusters, the parallel growth rate and the perpendicular one. This model enables to well describe the quantity of C-S-H precipitated versus time but also the surface developed by these hydrates in different experimental conditions.