Natural Localized Corrosion of Steel Bar in 44-Years Old Cracked RC Beam Structures Exposed to Marine Tidal Environment

Abstract

The chloride-induced corrosion processes of exposed structures are very complex. Locally isolated anodically and cathodically active steel surface areas may form on reinforcing bars of RC structures. Corrosion processes may only be examined indirectly using electrochemical methods due to the obscurity of the cathodically active steel surface areas. In this study, an experiment was undertaken to identify the development of natural corrosion on broken, 44-year-old RC structures exposed to the actual marine environment. Observation of the inadequate appearance of the concrete and electrochemical measurements were used to predict the probability of the deterioration phase. The greatest corrosion risk was recognized in the middle tensile section, and a check of the actual state of the steel bars was conducted there. Natural localized corrosions were obviously generated on the middle tensile steel bar of the pre-cracked RC beam as a result of the accelerated development of macro-cell corrosion current brought on by the first cracks in the constructions.