Corrosion Resistance of Stainless Steel Clad Reinforced Bars

Abstract

The corrosion resistance of No. 6 Type 316 stainless steel clad bars produced by Commercial Metals Company (CMC) was evaluated using the rapid macrocell and cracked beam tests (15 and 96 weeks, respectively), as described in the Annexes of ASTM A955. The bars were pickled in a 20% hydrochloric acid solution for five minutes, but exhibited some residue after the pickling process. Some bars were sandblasted and repickled at the University of Kansas to remove the residue; these repickled bars were also evaluated in the rapid macrocell test. Both the as received and repickled bars met the requirements of ASTM A955 when evaluated using the rapid macrocell test. Two of the bars evaluated in the cracked beam test exceeded the 0.5 μm/yr, the upper limit for corrosion rate specified in ASTM A955. Upon autopsy of the specimens, it was determined that corrosion only occurred on the cut ends of the bars and not the cladding itself. The stainless steel clad reinforcing bars evaluated in this study met the requirements of ASTM A955. It is recommended that protection of the cut ends of stainless steel clad bars be employed where the use of corrosion resistant reinforcing bars is required.