Multi-scale numerical simulation on mechanical strength of concrete based on its microstructural evolution

The aim of this paper is to numerically investigate the relationship between mechanical strength and micro- structural evolution of concrete, firstly, based on the geometrical characteristics of constituents, a multi-scale model of concrete was geometrically reconstructed; Secondly, a stress response equation of composite material at different scale of concrete was presented, and a multiscale model of concrete strength associated with stress response was proposed; Finally, after being verified, this model was utilized to conduct a numerical analysis on the characteristics of stress response and the mechanical strength of concrete in the curing process as well as the effect of microstructural characteristics on the strength of concrete. Results show that, the fact that the compressive strength of concrete is clearly greater than its tensile strength is attributed to the difference in the stress response under uniaxial compressive and tensile loading, while the mechanical strength of concrete is obviously affected by spatial orientation and geometric shape of hydration products in the microstructure.