Microstructure Determination of Calcium-Silicate-Hydrate Globules by Small-Angle Neutron Scattering

The basic building block of calcium-silicate-hydrate (C–S–H) gel, which is the major hydration product of a commercial Portland cement paste, is usually referred as “globule” in the Jennings’ colloidal model-II developed for C–S–H. The detailed nanostructure of the globule is so far not given quantitatively. In this paper, we determine the structural parameters of the building block with good accuracy by small-angle neutron scattering technique probing an extended interval of the scattering vector, Q, from 0.015–1.0 Å–1. In this Q-range an interlamellar peak at 0.65–0.80 Å–1is present, shifting as a function of the water content present in the C–S–H gel. This additional feature enables us to confirm the presence of a lamellar structure and determine the thicknesses of both the water and the hydrated calcium silicate layers respectively proper of the C–S–H globules.