Rapid Macrocell Tests of Enduramet® 2304 Stainless Steel Bars

Abstract

The corrosion performance of epoxy-coated steel meeting the requirements of ASTM A775 with the coating in an undamaged condition and two damaged conditions (0.04% and 0.83% damaged area) is evaluated in accordance with Annexes A1 and A2 of ASTM 955 and compared with the corrosion performance of conventional reinforcing steel meeting the requirements of ASTM A615 steel and low-carbon, chromium steel meeting the requirements of A1035, with the latter in both the as-received and pickled conditions. Epoxy-coated bars provide significantly better corrosion performance than conventional reinforcing steel. The macrocell corrosion rates for bars with a damaged area equal to 0.04% of the area exposed to the solutions in the test are relatively low, and are, on average, similar to those observed for the undamaged epoxy-coated bars. Both undamaged and 0.04% damaged area epoxy-coated specimens meet the requirements for stainless steels specified in Annexes A1 and A2 of ASTM 955, with an average corrosion rate not exceeding 0.25 μm/yr and the corrosion rate of no individual specimen exceeding 0.50 μm/yr. The macrocell corrosion rates for bars with a damaged area equal to 0.83% of the area exposed to the solutions in the test average 1 to 1.5 μm/yr based on total bar area under the severe exposure conditions provided. Conventional and A1035 steel exhibit average values near 30 μm/yr for and 20 μm/yr, respectively. Pickling provides initial protection to A1035 steel bars, and to some bars for the duration of the test, but once corrosion initiates, corrosion appears to be similar to that observed on non-pickled bars.