Abstract
With a soil resistivity less than 200 ohm-centimeter, tidal water table fluctuations, and a high potential for MIC (microbiologically influenced corrosion) activity, the Florida Everglades is one of the most corrosive underground environments in the United States. This paper discusses corrosion monitoring data of Ductile Iron Pipe in this harsh environment over a three-year period. In this study, uncoated, standard asphalt shopcoated, and polyethylene encased Ductile Iron Pipe were monitored. The evaluation included the use of electrical resistance type corrosion rate probes buried in the soil adjacent to the pipe and also between the pipe surface and encasement for the polyethylene encased pipe. Included were pipe to soil polarization characteristics determined through the application of a cathodic current to extend pipe service life by effectively reducing corrosion rates. The study illustrates that corrosion protection beyond the standard asphalt shopcoating and annealing oxide inherent to Ductile Iron Pipe may be warranted in such extremely corrosive environments as found in the Everglades.
