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 angstrom(-1). In this Q-range an interlamellar peak at 0.65-0.80 angstrom(-1) is 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.