Performance Testing of Two-Coat Zinc-Rich Systems on Steel Bridges

For a number of years, 3-coat, zinc-rich/epoxy/polyurethane systems have been identified as the best coating systems for protecting steel bridges from corrosion. However, application and curing of 3 coats takes a considerable amount of time. Generally, a highway needs to be closed for at least 1 day to complete the job of painting a highway overpass. New systems, 2-coat rather than 3-coat, are becoming more attractive for protecting steel bridges. The 2-coat systems consist of 1 zinc rich primer matched with 1 of 3 types of fast-dry, high build top coats: a polyaspartic, a polyurethane, or a polysiloxane. With the epoxy intermediate layer eliminated, a highway overpass can often be completely coated overnight. Conventional polyurea is known to cure very rapidly, but it needs special and expensive equipment to apply. Polyaspartics, a type of polyurea, not only dry fast but also can be applied at high thickness by a conventional spray gun, making applications less complicated. This so-called breakthrough technology for repainting bridges also minimizes the duration and public impact of work zones and has been recently used by some states. To investigate the feasibility of this new technology, the Federal Highway Administration (FHWA) conducted a study to compare the performance of these 2-coat, fast dry systems with the conventional 3-coat systems. This article presents and compares both laboratory accelerated and outdoor exposure results from the FHWA investigation.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/87551985
• Authors:
  • Chong, Shuang-Ling
  • Yao, Yuan
• Publication Date: 2006-6

Language

• English

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 72-83
• Serial:
  • Journal of Protective Coatings and Linings
  • Volume: 23
  • Issue Number: 6
  • Publisher: Technology Publishing Company
  • ISSN: 8755-1985

Subject/Index Terms

• TRT Terms: Coatings, fillers and paints; Corrosion protection; Highway maintenance; Maintenance practices; Metal bridges; Protective coatings; Work zones; Zinc coatings
• Identifier Terms: U.S. Federal Highway Administration
• Uncontrolled Terms: Polyurea coatings
• Subject Areas: Geotechnology; Highways; Maintenance and Preservation; Materials; I35: Miscellaneous Materials; I61: Equipment and Maintenance Methods;

Filing Info

• Accession Number: 01031632
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 24 2006 8:21AM