Corrosion Performance of Epoxy-Coated Reinforcement-Beam Tests

The performance of coated reinforcement under conditions that simulate a highly corrosive environment and under loading conditions producing concrete cracking was evaluated in a beam exposure test. Duplicate concrete beams were reinforced with unlinked coated and uncoated bars. Various arrangements of longitudinal bars, stirrups, and splices were considered. Coating condition was a variable to assess effects of damage and patching on performance. Some beams were uncracked while others were cracked and either unloaded or kept under load to maintain cracks at a specified maximum allowable crack width. Salt water flowed over the middle portions of beams in a cyclic wet and dry regime over a period of 112 14-day cycles (4.3 years). Loads were cycled on the cracked beams during wet and dry periods. The selection of the exposure procedure, test parameters, and specimen characteristics was intended to produce a very aggressive environment and to accelerate corrosion of the specimens. The state of corrosion activity on steel was monitored by corrosion potential measurements. Beam condition and changes in crack width were observed during exposure. Forensic examinations were conducted on each duplicate after 1 and 4.3 years to relate corrosion state findings to actual bar condition. Based on the findings, recommendations are provided for improving coating quality, fabrication and patching procedures. In addition, recommendations are given to minimize damage to coating and to control cracks in concrete.