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原文传递 Durability Performance of Submerged Concrete Structures - Phase 2. Final Report 02/10/2011-09/30/2015.

题名：	Durability Performance of Submerged Concrete Structures - Phase 2. Final Report 02/10/2011-09/30/2015.
作者：	Walsh, M. T.; Sagues, A. A.
关键词：	Bridges, Reinforced concrete, Corrosion, Reinforcing steel, Durability, Concrete
摘要：	This project determined that severe corrosion of steel can occur in the submerged portions of reinforced concrete structures in marine environments. Field studies of decommissioned pilings from Florida bridges revealed multiple instances of strong corrosion localization, showing appreciable local loss of steel cross-section. Quantitative understanding of the phenomenon and its causes has been developed, and a predictive model was created based on that understanding. Corrosion rate estimates and the extent of corrosion localization from the field observations were consistent with the results of the predictive model. The most likely explanation for the phenomenon is that cathodic reaction rates under oxygen diffusional limitation that are negligible in cases of uniform corrosion can support substantial corrosion rates in cases of localized corrosion. Modeling projected that, with use of sacrificial anode cathodic protection, corrosion in the submerged zone could be virtually eliminated, together with significant reduction of the rate of corrosion damage progression in the low elevation zone above water. Continuation work should be conducted to define an alternative limit state other than visible external cracks and spalls for submerged reinforced concrete, and for determination of the possible structural consequences of this form of corrosion, as well as to assess the technical feasibility and cost/benefit aspects of incorporating protective anodes in new pilings.
总页数：	Walsh, M. T.; Sagues, A. A.
报告类型：	科技报告