A composite calcium silicate hydrate model of molecular dynamics simulations for mechanical properties

Many researches have been conducted to study the properties of calcium silicate hydrate (C-S-H) using numerical modeling. However, there still exists a large gap between the mechanical characteristics of C-S-H. A new composite C-S-Hs model is proposed to more realistically represent the layered feature in this paper. Compared with regularly-arranged C-S-Hs model, larger interlayer space provides sufficient space for water adsorption and the arrangement of C-S-H cells. The random arrangement of multiple C-S-H cells and additional water molecule adsorption have a significant impact on the composite C-S-Hs system. Uniaxial tension tests with different strain rates are utilized to investigate the mechanical properties of the composite C-S-Hs model compared with those of regularly arranged C-S-H cells. The simulation results demonstrate that the mechanical properties of the composite C-S-Hs model are closer to those of cementitious materials on the macroscopic scale. The simulation results highlight the impact of strain rate and interlayer spacing on the characteristics of the multiple C-S-Hs model. The proposed composite C-S-Hs model provides a more reasonable procedure for molecular dynamics simulation of C-S-H.