Chemo-mechanical analysis of concrete cracking and degradation due to external sulfate attack: A meso-scale model

In this paper we focus on the external sulfate attack on concrete specimens at the meso-level. There is nowadays a renewed interest in rationally describing the mechanisms behind expansive processes leading to cracking and spalling of concrete exposed to sulfate solutions. A model is presented for degradation of concrete exposed to external sulfate attack at the meso-level, i.e. representing explicitly in the simulations the main heterogeneities of the material. A previously developed mesomechanical approach has been coupled with a diffusion–reaction analysis at the same scale. It is based on the systematic use of zero-thickness interface elements equipped with fracture-based constitutive laws, and the effect of discrete cracks on the transport of ions is explicitly accounted for. The main results obtained agree qualitatively and quantitatively well with experimental observations in terms of ettringite penetration depth, expansions, crack patterns and spalling effects.