Water‐induced failure mechanics for concrete

This work outlines a micro‐mechanical framework for modeling water‐induced damage mechanism of concrete. Concrete has a highly heterogeneous micro‐structure and its composite behavior is very complex. Due to that various effects must be considered for analyzing failure response at micro scale, e.g. modeling the solid skeleton, fluid bulk phases and their interaction. For obtaining a deeper understanding of the influence of water on the concrete at the micro‐level, a micro‐computed‐tomography (micro‐CT) scan has been conducted at IfB to illustrate the micro‐structure geometry and concrete content. These data are required to build the constitutive model and the design of the numerical simulations, in line with [1]. Then a micro‐mechanical model is developed for the coupled problem of fluid‐saturated heterogeneous porous media at fracture. The modeling of microscopic cracks in porous heterogeneous media can be achieved in a convenient way by a continuum phase‐field approach, which is based on the regularization of sharp crack discontinuities [2,3]. This avoids the use of complex discretization methods for crack discontinuities, and can account for complex crack patterns. The numerical examples proposed in this contribution stem out from the DFG Priority Program SPP 2020 “ Cyclic Damage Processes in High‐Performance Concretes in the Experimental Virtual Lab ”.