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

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 similar to 3 x 3 x 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.