Long-term corrosion behaviour of stainless reinforcing steel in mortar exposed to chloride environment

Long-term corrosion behaviour of six stainless reinforcing steels embedded in mortar and exposed to chloride media was monitored by electrochemical impedance spectroscopy at the open circuit potential during the period of 2 years. Corrosion behaviour of studied steels was divided into two phases characterized by different interfacial behaviour: (i) passive phase and (ii) pitting propagation phase. After 2 years, duplex steel 1.4362 showed very good corrosion performance similar to austenitic steel 1.4401. Steel types with low Ni content but with high N and Mn content, 1.4597 and 1.4162, showed lower corrosion resistance compared to austenitic steel 1.4301.

► Stainless steel reinforced mortar exposed to aggressive solution for 2 years.
► Impedance spectra of passive and corroding stainless steel in mortar discussed.
► Real-time behaviour in mortar compared to literature pore solution results.
► Steels ranked based on their composition, performance and corrosion attack morphology.