The morphology of a one month old hydrated C3S paste has been studied using the scanning electron microscope (SEM) and preferential etching techniques. The C/S ratios of the calcium silicate hydrates (CSH) have been determined using the SEM with an energy dispersive spectrometer. The hydrate rims covering the partially hydrated C3S grains were found to consist of two layers; an outer porous product with an acicular morphology having a C/S ratio of 1.6 ± 0.1 and an inner product with a C/S ratio of 1.90 ± 0.05. A region of increased C/S ratio in the C3S core at the C3S-CSH interface is attributed to a depletion of SiO2resulting from the diffusion of Si4+ions into the hydrate. © 1977.
Stucke, M. S., & Majumdar, A. J. (1977). The morphology and composition of an immature C3S paste. Cement and Concrete Research, 7(6), 711–718. https://doi.org/10.1016/0008-8846(77)90055-2