The performance of austenitic and duplex stainless steels in cracked concrete exposed to concentrated chloride brine

摘要

In order to meet the service life requirements of highway structures, which are most commonly limited by corrosion of the carbon steel reinforcing bars, many jurisdictions are turning to stainless steel as an alternative reinforcing material. To address this application, several stainless steel producers have developed less costly grades than the "traditional" UNS S30453, UNS S31653 and UNS S32205 alloys. The goal of this project has been to determine if these alloys can resist the highly concentrated anti-icing salt brines used in Ontario, Canada, when embedded in "realistic" concrete, complete with load-induced cracks. The results indicate that the duplex grades of stainless steel perform slightly better than do the austenitic grades. All the six grades showed some signs of corrosion at the intersection of the cracks with the bars, while none of them exhibited any indication of corrosion in sound (non-cracked) concrete.