X-ray computed tomography images based phase-field modeling of mesoscopic failure in concrete

Crack nucleation and propagation in concrete is significantly affected by mesoscopic heterogeneities, resulting in distinct failure modes and mechanical behavior. In this work, the phasefield regularized cohesive zone model (PF-CZM) is combined with the X-ray computed tomography (XCT) imaging technique and applied to the modeling of mesoscopic cracking in concrete. More specifically, the in situ XCT image is employed to build the finite element discretization of concrete meso-structure, and the PF-CZM with the Cornelissen et al. (1986) softening law is adopted to model the interfacial transition zone (ITZ) and the matrix. The combined XCT and PF-CZM method is validated by Monto Carlo simulations of concrete samples under uniaxial tension. The influence of mesoscopic heterogeneities on the peak load and crack pattern is then investigated with respect to three- and four-point bending beams with various pre-notch depths. Numerical results show that, as the combined XCT and PF-CZM method takes mesoscopic heterogeneities and material inelasticities into account simultaneously, it is very promising for the modeling of damage and failure in concrete.