Thermal Spray Zinc Coatings for Corrosion Protection of Steel Bridges

Steel bridges in Norway are exposed to harsh corrosive environments along sea coasts and through the use of road de-icing salts. Since 1965, thermal sprayed zinc coatings have been used in Norway to minimize coating maintenance on steel bridges, sometimes with coating lifetimes of more than 40 years. The specification of thermal sprayed metallic zinc coatings with a paint top-coat, or ‘Duplex Coatings’, provides the bridges of Norway with both barrier and sacrificial corrosion protection mechanisms, with improved impact and abrasion resistance, and much longer lifetimes between maintenance compared to paint only coatings. Duplex zinc coatings provide more than twice the life of the corrosion protection provided by one coating system alone. A paint top-coat over a metallic zinc base layer protects the zinc from initial corrosion. The zinc base layer similarly protects the paint from underfilm corrosion at scratches and holes. The synergy between the two coatings provides protection far superior to either system used independently. Empirical evidence shows that, depending on the environment, duplex zinc coatings will provide 1.5 to 2.3 times the sum of the expected life of each system alone. Life cycle cost analyses confirm the significant savings from reduced maintenance over the life of a structure. The use of duplex zinc coating systems on steel bridges in Norway have provided decades of proven performance protecting steel infrastructure from corrosion. Case studies will show the economic benefits of reduced maintenance costs of interest to new or existing steel bridge owners.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AHD45 Standing Committee on Corrosion.
• Corporate Authors:

  Transportation Research Board

  ,    
• Authors:
  • Gagne, Martin
  • Goodwin, Frank E.
  • Knudsen, Ole Øystein
  • van Leeuwen, Martin
• Conference:
  • Transportation Research Board 98th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2019-1-13 to 2019-1-17
• Date: 2019

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 10p

Subject/Index Terms

• TRT Terms: Coatings; Corrosion; Corrosion protection; Maintenance; Steel bridges; Zinc coatings
• Subject Areas: Bridges and other structures; Highways; Maintenance and Preservation; Materials;

Filing Info

• Accession Number: 01697299
• Record Type: Publication
• Report/Paper Numbers: 19-01337
• Files: TRIS, TRB, ATRI
• Created Date: Mar 1 2019 3:50PM