Fully coupled diffusion-damage analysis in historical masonry walls

Historical masonry structures are affected by a complex deterioration process, mainly due by the interaction of mechanical and physical/chemical condition. For this reason, in this field of constructions the mechanical performance cannot be evaluated apart from the the environmental deterioration. Considering this scenario a preliminary work has been recently proposed in [1] for a mechanical model of damage and friction analysis of masonry walls, embedding also the environmental deterioration. The model employed is capable, for a particular mechanical damage state, to simulate the mass flux of external agents as influenced by the mechanical damage. Due by a lacking of specific literature for these types of structures, diffusion has been accounted addressing to models which couple these phenomena for other materials, see for example [2]-[3]. In this paper we address the extension of this preliminary work to a full coupling of these two deterioration agents. The time evolution of the mechanical damage, based on the model of brick-by-brick interaction proposed in [4] within a computational multi-scale approach, is coupled with the time evolution of the environmental action. The diffusion of penetrating agents inside the masonry affects the constitutive relations step by step during the considered time slot. The aim is to evaluate possible equilibrium condition between the two phenomena even though they have very different evolution time, in order to assess valuable structural information. Numerical tests are used to show the effectiveness of the proposed approach.