Analytic model of non-uniform corrosion induced cracking of reinforced concrete structure

Abstract

In order to perfectly reflect the dynamic corrosion of reinforced concrete (RC) cover in practical engineering, an analytic model of non-uniform corrosion induced cracking was presented based on the elastic-plastic fracture mechanics theory. Comparisons with the published experimental data show that the predictions given by the present model are in good agreement with the results both for natural exposed experiments and short-time indoor tests (the best difference is about 2.7%). Also it obviously provides much better precision than those models under the assumption of uniform corrosion (the maximal improved precision is about 48%). Therefore, it is pointed out that the so-called uniform corrosion models to describe the cover cracking of RC should be adopted cautiously. Finally, the influences of thickness of local rusty layer around the reinforcing steel bar on the critical corrosion-induced crack indexes were investigated. It is found that the thickness of local rusty layer has great effect on the critical mass loss of reinforcing steel, threshold expansion pressure, and time to cover cracking. For local rusty layer thickness with a size of a = 0.5 mm, the time to cover cracking will increase by about one times when a/b (a, semi-minor axis; b, semi-major axis) changes from 0.1 to 1 mm.