Hygro-mechanical modeling of cracked concrete in the framework of the X-FEM

Consideration of moisture transport in addition to external loading is a prerequisite for reliable durability analyses of structures made of concrete. The presentation is concerned with the modeling of cohesive cracks in partially saturated cementitious materials using the Extended Finite Element Method (X-FEM), focussing on the interactions between cracks and moisture transport. To this end, a coupled hygro-mechanical model for partially saturated concrete is extended for the consideration of cracks in the context of a 3D X-FEM model. Moisture flow within crack planes is accounted for by assuming Poiseuille flow within the crack planes, taking the tortuousity and the crack width dependence of the liquid permeability within cracks into account. For the three-dimensional implementation of the X-FEM formulation a higher-order spatial discretization concept based on Legendre polynomials is used. The applicability of the hygro-mechanical X-FEM-model is investigated by means of a representative 3D benchmark example considering a hygro-mechanical loading scenario.