POLARISATION EFFECT ON CONCRETE CATHODIC PROTECTION CRITERIA

摘要

Although cathodic protection (CP) to the above ground reinforced concrete structures was first applied around 30 years ago, the CP criteria for such application are still being researched. Among all the currently used CP criteria, the 100 mV potential decay criterion is considered to be the most pragmatic and generally achievable. There are some laboratory studies that suggest to formulate a "current density" criterion as a step forward. The current density requirement, however, decreases with time, to maintain the same level of polarization/depolarization such as 100mV decay. The relationship between the current density and polarization level & period is discussed in this paper. Laboratory study results and the relevant data from an actual installation are presented. It is shown that the current density requirement to achieve a particular level of polarization decreases with time as expected.