Nano–micro modelling of mechanical properties of cement paste based on molecular dynamics

Abstract

The elastic properties and tensile strength of cement paste were investigated from a theoretical viewpoint. By means of molecular dynamics (MD) simulations, the Mori–Tanaka homogenisation method and Griffith fracture theory, a comprehensive methodology was developed to explore the mechanical properties of cement paste from nanoscale to microscale. A series of nanostructures representing the main constituents of cement paste was constructed and analysed in the light of MD simulations, in which microporomechanics analysis was conducted to consider the influence of gel porosity. The outcomes were then upscaled for the elastic constants of cement paste using the Mori–Tanaka homogenisation method. Finally, the tensile strength of cement paste was obtained according to Griffith fracture theory. The calculation results were in good agreement with the experimental data, which shows that the multiscale coupling method based on MD is capable of capturing the mechanical properties of cement paste from the atomic scale, thus providing a new perspective on the multiscale study of cement-based materials.