Weaving the next-level structure of calcium silicate hydrate at the submicron scale via a remapping algorithm from coarse-grained to all-atom model

The submicron scale is a critical bridge connecting the nanoscale molecular dynamics simulations to the microscale mechanical experiments like nanoindentation. Here we present a modeling algorithm for submicron structure of calcium silicate hydrate (C-S-H). The algorithm remaps coarse-grained C-S-H models back to all-atom models through Voronoi analysis on packing of disk-like units. The obtained all-atom model is in a polycrystalline form composed of densely packed C-S-H grains and water shells. The all-atom model inherits well-accepted C-S-H structuring patterns and shows reasonable structures comparable to experimental observations. The mechanical properties of C-S-H are studied and a direct simulation of nanoindentation test is presented at the length scale of 50 nm. The proposed modeling algorithm contributes to closing the gap between experiments and molecular simulations which were at different length scales and could help explore emergent phenomena of cement at length scales up to a hundred nanometers.