Abstract
When passive steel is cathodically polarized by nearby previously corroding steel, the local value of chloride corrosion CT could increase substantially, slowing down the spread of corrosion. The potential-dependent threshold (PDT) effect was introduced in an initiation-propagation mathematical model that simulated a partially submerged reinforced concrete column in sea water. Results indicated that when PDT is ignored, meaning a system with potential-independent threshold (PIT), the corrosion damage prediction can be overly conservative and may lead to structural overdesign. This issue is disregarded by present forecast models which assume only time invariant CT values. Implementation of PDT is desirable but developing a mathematical model that forecasts the corrosion damage of an entire marine structure with a fully implemented PDT module may result in excessive computational complexity. This paper introduces an alternative, less computationally demanding module by incorporating PDT as an added feature to a traditional PIT forecasting model. A library of PDT and PIT paired cases were computed by changing the model input parameters over a wide range of values. Short-term and long-term corrosion damage outputs with PIT and PDT were statistically analyzed to identify a time-dependent, generic correction factor to adjust the corrosion damage functions estimated with the traditional PIT approach.
