摘要: |
A critical literature review regarding high-performance reinforcement for concrete bridge applications was conducted. This included (1) an overview of the corrosion-induced concrete deterioration process, (2) corrosion control alternatives, (3) the utility of corrosion (pitting) resistant alloys for applications in chloride containing environments, (4) a review of the pitting mechanism, and (5) performance of various metallic reinforcement types in aqueous solutions, cementitious embedments, test yard exposures, and actual structures. Specific alloys upon which attention was directed include black steel; MMFX-II; and various grades of ferritic, austenitic, and duplex stainless steels, as both solid and clad bars and in the as-received and pickled conditions. It was determined that the high-performance alloys outperformed black steel from a corrosion resistance standpoint. Unlike the various grades of black steel, however, a relatively wide range of corrosion performance was apparent for the high-performance counterparts depending upon the alloy and surface condition. At the same time, the present approach to materials selection for bridge construction is to identify the reinforcement candidate that will achieve the design life at the least life cycle cost. This, in turn requires that long-term corrosion performance of candidate reinforcement types be known for the anticipated design life of the bridge in question, which can be 75100 years. However, because service history for these materials in this application is limited, the necessary information can only be obtained from accelerated, short-term tests, but there is no reliable correlation between the results from these tests and long-term performance. |