ABSTRACT
Abstract This paper deals with the effect of Interfacial Transition Zone damage due to loading on chloride penetration in reinforced high performance and normal concrete. The quantification of ITZ damage is related to the tensile stress in re-bar and then the modification of diffusion is modeled in relation to this tensile stress. Keywords: ITZ, chloride, diffusion coefficient, damage, tensile strength
1 Introduction
This study is an attempt to characterize the influence of concrete microcracks due to the service load of reinforced structure on the chloride diffusivity. As a result, this concrete damage which is basically located at the ITZ of concrete could lead to a significant effect on long-term prediction of chloride profiles in reinforced concrete structures. To understand and model this effect, an experimental program was built using reinforcing ties made with Ordinary Concrete, High Strength Concrete and Very High Strength Concrete. These ties were stored in a chloride environment over one week periods of wet-humid cycles in a salt fog enclosure. The main originality of this experimental program is that the ties are stored in tensile state, i.e. both cracks and micro-cracks are still opened during the chloride ingress. In this paper, we first characterize concrete damage due to loading, then secondly we analyze the chloride diffusivity in the different concretes to finally propose a model for the increase in diffusivity in relation to load level.
