2D Crack Propagation in High-Strength Concrete Using Multiscale Modeling

Abstract

In this work a concurrent multiscale (macro and mesoscale) approach for high-strength concrete (HSC) is proposed for seeking to better understand the influence of coarse aggregate type, shape, and size distribution as well as the interfacial transition zone (ITZ) effects on the fracture mechanical responses. A linear elastic model with homogenized elastic properties is used for the macroscale, while a three-phase material composed of coarse aggregates, mortar matrix and the ITZ equipped with nonlinear behavior models are assumed for the mesoscopic level. To geometrically represent and gain insights into effects of coarse aggregates, two polygonal shapes are assumed: irregular quadrilateral and regular octagonal forms, which are used separated and randomly generated from a given grading curve and placed in the mesoscale region using the “take-and-place” method. A mesh fragmentation technique is used to explicitly represent the crack propagation process by considering the individual behavior of each phase as well as their mutual interactions. The non-matching macro and mesoscopic meshes are attached based on the use of coupling finite elements in the context of the rigid coupling scheme to adequately guarantee the continuity of displacement between both scales. Numerical analyses of dog-bone shape specimens under tensile load and three-point bending beams were performed. The responses obtained numerically show a good agreement with experimental ones found in literature demonstrating how the proposed approach is efficient, robust and useful for modeling crack propagation in HSC.