Study of C-S-H growth on C3S surface during its early hydration

Abstract

A study to understand and quantify the growth mode of C-S-H during the hydration of tricalcium silicate grains is presented here based upon number of complementary approaches: study of C-S-H nucleation during the hydration of tricalcium silicate compared with experimental studies of homogeneous nucleation; experimental kinetics studies of C-S-H formation during tricalcium silicate hydration in dilute suspensions; direct observations of C-S-H growth by Atomic Force Microscopy; Simulation of curves obtained from experiments in dilute suspensions from a model based on AFM observations. With AFM the formation of CSH is observed by the agglomeration of identical elements 60×30×5 nm3 in size on alite surface. This agglomeration takes place perpendicularly and parallel to the surface. Numerical simulation of the experimental curves of the degree of hydration versus time enabled us to quantify the variation of the growth rates parallel and perpendicular to the surface with lime concentration. It is shown that the growth rate of C-S-H only depends on the lime concentration in solution.