Korrosion rostfreier Stähle in chloridhaltigem und karbonatisiertem Beton / Corrosion Behaviour of Stainless Steels in Chloride Contaminated and Carbonated Concrete

The paper deals with the corrosion resistance of different stainless steels in chloride contaminated and carbonated concrete. Stainless steel reinforcement has a higher corrosion resistance as compared to the normal carbon steel reinforcement; stainless steels can, however, be subject to localized corrosion if the chloride content in the concrete exceeds a certain critical value. This critical value depends on the pH value of the concrete (i.e. carbonated or alkaline concrete), the temperature, the corrosion potential (function of environmental conditions), and the composition and microstructure of the stainless steel. Furthermore, in the rehabilitation of corroding reinforced concrete structures, stainless steel is often used in structures reinforced with normal carbon steel and galvanic coupling can occur. The results of measurements of free corrosion potential, corrosion rate and macrocouple current in reinforced concrete specimens are reported as a function of chloride concentration and humidity. The consequence of coupling with carbon steel reinforcement is also considered.