Stainless Steel Reinforcement as a Replacement for Epoxy Coated Steel in Bridge Decks

Abstract

The performance of different types of reinforcement in concrete bridge decks is evaluated in this study. Application of deicing salts has directly led to deterioration of roadway bridge decks due the corrosion of reinforcing steel. Epoxy-coated reinforcement (ECR) is currently the most commonly used alternative in this application; however, it does not guarantee a long lifespan. In some cases, poorly adhering epoxy coatings have resulted in increased corrosion rates, which is a concern for all epoxy coatings. As a comparison, two types of stainless reinforcing steel are evaluated; a 2304 duplex stainless steel and NX-SCRTM stainless steel clad bars, alongside conventional reinforcement and ECR. Upon the completion of testing, the projected cost of each system will be calculated to determine if the increased initial costs can be justified over a design life. Two tests are performed on specimens – a 15 week rapid macrocell test and a series of 96 week bench-scale tests. Completed test results for the rapid macorcell tests are presented, while bench-scale tests are partially completed with specimens aged 26-31 weeks. Results have shown that ECR and stainless steel reinforcement perform better in test media than conventional reinforcement. Pickling 2304 duplex stainless steel bars has a considerable effect on the performance of test specimens, with as-received bars failing ASTM A955 limits on corrosion rates in rapid macrocell and cracked beam tests. Repickling a series of specimens for rapid macrocell testing resulted in a passing of these test limits. Bending stainless steel clad reinforcement did not cause the specimens to exceed the maximum corrosion rate threshold to be surpassed in rapid macrocell testing, while corrosion initiation has not yet occurred in Southern Exposure specimens. Upon initiation, chloride contents at the level of reinforcement are lowest for conventional steel and highest for damaged stainless steel clad specimens.