Title: Corrosion Study of Stainless Steel Bars in Cracked Concrete
Author(s): T. Yamaji, T. Hirasaki, R. Takahashi, S. Mizuma,
and M. Yamakawa
Publication: Symposium Paper
Appears on pages(s): 155-170
Keywords: chloride; corrosion; cracked concrete; stainless steel
Corrosion of stainless steel bars in concrete was investigated using sound and pre-cracked concrete specimens. Three types of stainless steel were investigated, such as 18Cr, 18Cr-8Ni and 18Cr-12Ni-2.5Mo. Concrete specimens were exposed to two environments, where wetting and drying alternately repeated. One was in the outdoor with atmospheric temperature, and the other was in a controlled chamber, where the temperature was 60°C during wetting and 15°C during drying. The detail investigation was carried out after two years. No corrosion was observed on stainless steel bar in both sound and pre-cracked concrete exposed to outdoor. The maximum chloride ion concentration was 7.0 kg/m3 for 18Cr-8Ni, 8.0 kg/m3 for 18Cr-12Ni-2.5Mo and 6.0 kg/m3 for 18Cr at the crack region of concrete. This result indicated that the chloride ion threshold level for stainless steel was larger than these values under marine environment with atmospheric temperature. No corrosion was observed on both 18Cr-12M-2.Wo and 18Cr in both sound and pre-cracked concrete exposed to controlled chamber. However, corrosion was observed only for 18Cr-8Ni at the crack region, even when the chloride ion concentration at the crack region was 6.0 kg/m3. This was considered to be due to the effect of a high temperature.