Molecular dynamics study on the structure and mechanical properties of tobermorite

The calcium silicate hydrate (C-S-H) structure has been indicated its atomic structure in the early stage of hydration resembles the geometry of tobermorite which is a natural calcium silicate hydrate. The mechanical properties of tobermorite crystals were investigated based on molecular dynamics (MD) method in this study. Uniaxial tension simulation in the z-direction was performed to the layered structure of tobermorite 9 Å, 11 Å and 14 Å at molecular level. The stress–strain relationships were obtained, and the structure analysis of tobermorite was carried out in terms of the relative concentration profile and mean square displacement. It has been found that tobermorite 9 Å has the greatest tensile strength compared with tobermorite 11 Å and 14 Å. It also shows that strong interaction between interlayer Ca ions and silicon-oxygen tetrahedra will increase the resistance of tensile loading. These findings may contribute to have a deep knowledge of the intrinsic property of C-S-H.