Environmentally Acceptable Materials for the Corrosion Protection of Steel Bridges

Details

• Creators:
  Kogler, Robert ; Ault, J. Peter ; Farschon, Christopher L.
• Corporate Creators:
  United States. Federal Highway Administration. Office of Engineering Research and Development
• Contributors:
  Peart, John W.
• Corporate Contributors:
  Ocean City Research Corporation ; Turner-Fairbank Highway Research Center
• Subject/TRT Terms:
  Anticorrosion Coatings Corrosion Protection Life Cycle Costing Steel Bridges
• Publication/ Report Number:
  FHWA-RD-96-058
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Contracting Officer:
  Peart, John W.
• Corporate Publisher:
  United States. Federal Highway Administration. Office of Engineering Research and Development
• Abstract:
  The recently promulgated environmental regulations concerning volatile organic compounds (VOC) and certain hazardous heavy metals have had a great impact on the bridge painting industry. As a response to these regulations, many of the major coating manufacturers now offer "environmentally acceptable" alternative coating systems to replace those traditionally used on bridge structures. The Federal Highway Administration sponsored a 7-year study to determine the relative corrosion control performance of these newly available coating systems. A battery of accelerated laboratory tests were performed on candidate coating materials with a maximum VOC content of 340 g/L (2.8 lb/gal). Accelerated tests included cyclic salt fog/natural marine exposure, cyclic brine immersion/natural marine exposure, and natural marine exposure testing. Natural exposure test panels were exposed and evaluated for a total of 6.5 years. The most promising coating systems were selected for long-term field evaluation based on accelerated test performance. The long-term exposure testing was conducted for 5 years in three marine locations. Panels were exposed on two bridges, one in New Jersey and one in southern Louisiana. The third long-term exposure location was in Sea Isle City, New Jersey. Thirteen coating systems were included for long-term exposure testing. These included 2 high-VOC controls and 11 test systems having a VOC level of 340 g/L (2.8 lb/gal) or less. Five of the test systems contained high-solids primers, two of the test systems contained waterborne primers, one system was based on a powder coating, and three systems were metallizing. The best performing systems were the three metallized coatings. These were initially less aesthetic than coating systems with high-gloss topcoats, but they displayed near-perfect corrosion performance after 5- to 6.5-year exposure periods. Of the traditional liquid applied coating systems, those incorporating inorganic zinc primers performed the best over near-white blasted and power-tool cleaned surfaces. High-solids epoxy coatings had a tendency to undercut at intentional scribes and rust worse than coatings with zinc-rich primers over less than ideal surface preparations. Current bridge painting methodologies and corrosiveness of various bridge substructures were investigated. Various bridge maintenance painting options were evaluated on a life-cycle cost basis using data developed in the program. The analysis points to the potential advantages of long-term durable coatings such as metallizing and alternative painting practices such as zone painting.
• Format:
  PDF
• Funding:
  DTFH61-88-C-00010
• Collection(s):
  Federal Highway Administration
• Main Document Checksum:
  urn:sha-512:5b97e4f434b223be8a2648b24485a12764240e9fc511f415802c652a8d79571f26f8525a752b5ae53c834dc598da3e91ec374bc33862bdbe8d1ec815b869ff51
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/41914/dot_41914_DS1.pdf
• File Type:
  [PDF - 59.27 MB ]