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Publication Number: FHWA-HRT-11-046
Date: June 2011

Performance Evaluation of One-Coat Systems for New Steel Bridges


  • Although some of the one-coat systems demonstrated promising performance, none of them performed as well as the three-coat system in ALT and the outdoor exposure conditions.

  • HRCSA performed well in both ALT and outdoor exposures. While HRCSA is limited by its tenderness for a significant amount of time after application, it presents an interesting alternative for maintenance applications on existing structures.

  • Several of the one-coat systems showed encouraging performance in ALT and outdoor exposure conditions in terms of surface failures and rust creepage. GFP and the HBAC were among the better performing candidates.

  • Comprehensive performance evaluation showed that the three-coat control was the best performing system, followed by HRCSA, HBAC, and WBEP.

  • The two-coat control developed a large number of coating defects in ALT and had significant gloss reduction and rust creepage in outdoor exposure conditions, resulting in a low overall ranking.

  • Regression analysis was used to determine the functional relationship between pairs of performance parameters in a specific exposure condition and exposure conditions for a specific performance parameter.

  • Color correlated with gloss in all exposure conditions, and coating defects correlated with adhesion strength variation of unscribed panels in NW.

  • NW correlated with NWS for color, gloss, and adhesion strength variations. Similarly, adhesion strength variations of unscribed panels in ME correlated with that of NWS.
United States Department of Transportation - Federal Highway Administration