This report assesses (1) the rate of corrosion of bare steel with and without cathodic protection, and (2) the effectiveness of various commercially available coating systems in preventing corrosion of steel piles in seawater. Eighteen coatings and four sacrificial anodes were tested on 24 sets (three piles per set) of ASTM A 36 or ASTM 690 steel H-piles exposed for 5 years at Buzzards Bay, Massachusetts. Performance ratings were established for the following coatings: organic, organic over metal-filled, organic over metal-filled with cathodic protection, metallic organic over metallic, and organic with cathodic protection. It is concluded that sacrificial anodes of zinc and aluminum effectively reduced the corrosion rate of bare carbon steel (ASTM 36) piles in the immersed zone from 0.076-0.102 mm/yr (3-4 mils/yr) to zero, and the coating performing best was coal tar epoxy over zinc-rich primer.

You do not currently have access to this content.