Three-dimensional micromechanical modeling of concrete degradation under multiphysics fields

Concrete is a typical composite material including multiple phases. Concrete however is commonly treated as a homogeneous material in structural designs for the calculation of stress and strain. Moreover, concrete structures in service are subject to various mechanical and environmental loads. In design practices, these loads are handled separately without considering their interactions that could cause accelerated material degradation and unsafe designs. This work presents a finite element method (FEM) based model developed for studying concrete degradation by the synergistic interactions of applied mechanical and environmental loads with due consideration of the 3D microstructure of concrete that is reconstructed using the X-ray computed tomography (CT) technique. The degradation of a roadway concrete slab was simulated using the developed model. The results show that the microstructure of concrete matrix plays an important role in the distributions of stress and strain in concrete and that the effects of moisture and temperature in concrete are significant comparing to the effect of wheel load. This 3D microstructural multiphysics model can be used for design and non-destructive assessment of concrete structures of special shapes and needs, e.g., nuclear reactor vessels, which have high complexity and require high accuracy.