2686: Investigation of Stress Corrosion Cracking Susceptibility of High Strength Stainless Steels for Use as Strand Material in Prestressed Concrete Construction in a Marine Environment

Stainless steel reinforcing has an elevated chloride threshold and is an attractive alternative for prestressed concrete applications. However, due to the high strength requirements for prestressing strands, concern exists about the possibility of stress corrosion cracking (SCC). This investigation screened for potential SCC development three candidate high strength alloys for use as prestressed strands in a Florida marine environments. The alloys were a common austenitic stainless steel with high nickel content UNS # S31603, a less common austenitic stainless steel with low nickel but high manganese UNS# S24000, and a duplex stainless steel with high chromium and an additional constituent, molybdenum UNS# S32205. The alloys were evaluated at various temperatures in MgCl2 solutions and also in a simulated concrete pore water solution at 60 C, followed by an anodic polarization regime as an alternative test acceleration method. The results suggest that duplex highstrength stainless UNS# S32205 performed overall better than the other two alloys.