Polarization measurements were conducted over a 21-year period on bare and coated steel "H" pilings 6 inch by 6 inch by 30 feet (15.2 cm by 15.2 cm by 9.1 m) installed in seawater. A DC power source was used to shift from the corrosion potential of each pile to -0.85V. The amount of potential shift was recorded as 6V. The current (6I) required to shift the potential was measured, and a nonlinear pseudoresistance (6V/6I), called the Cathodic Protection Index (CPI), was calculated. The CPI was compared with the coating condition of the steel pilings as determined visually using ASTM standards. Results of these tests will be presented and discussed.
Various polymeric coatings have been exposed to natural saltwater environments in Buzzard' s Bay, MA and at La Costa Island, FL for the last 18 years and 21 years respectively. The coating systems were applied to 8 inch (20.32 cm) by 8 inch (20.32 cm) by 40 feet (12.19 m) A36 steel "H" pilings. The depth of the water ranged from 4 feet (1.22 m) to 8 feet (2.44 m). Periodic visual inspections have been conducted to evaluate the performance of the coating/ primer systems in the splash zone and in the immersed zone. The coatings had windows to evaluate the under film corrosion attack by saltwater present near the Cape Cod canal. The coatings were evaluated according to ASTM visual standards at low tide. Results of the coating inspections and an evaluation of their effectiveness in preventing the corrosion of steel pilings in seawater will be presented.