The nano-branched structure of cementitious calcium–silicate–hydrate gel

Abstract

Manipulation of concrete at the nanoscale is severely limited by the lack of precise knowledge on the nanostructure of calcium–silicate–hydrate gel, the main binding phase of cement-based materials. Here we report a computational description of C–S–H, which for the first time reconciles the existing structural and colloidal/gel-like models. Our molecular dynamic simulations predict the formation of a branched three-dimensional C–S–H solid network where the segmental branches (SB) are ∼3 × 3 × 6 nm-sized. The presented simulations account well for the features observed through Small Angle Neutron Scattering (SANS) experiments as well with various observations made by synchrotron X-ray, Nuclear Magnetic Resonance (NMR), and Inelastic Neutron Spectroscopy (INS) measurements and lead to a better understanding of the cementitious nanostructure formation and morphology.