Susceptibility to stress corrosion cracking of a prestressing steel in NaHCO3 solutions

Abstract

Prestressing concrete with steel strands or rods is a widely used method of construction. Although steel is usually protected against corrosion in concrete, prestressing steel can suffer stress corrosion. In the present paper the stress corrosion cracking (SCC) phenomenon is studied by means of electrochemical and slow strain rate tests performed on a prestressing steel immersed in NaHCO3 solutions. The results have shown that this steel is susceptible to SCC in this environment. The failure mainly depends on the NaHCO3 concentration, O2 content and the potential at which the steel is tested. A critical NaHCO3 concentration (0.1 M in aerated solution) has been identified. Cracking also occurs in more concentrated NaHCO3 solutions but with lower proportions of dissolved oxygen. The morphology of the fracture seems to be very similar to that observed when hydrogen embrittlement occurs.