Performance Evaluation of One-Coat Systems for New Steel Bridges

摘要

In an effort to address cost issues associated with shop application of conventional three-coat systems, the Federal Highway Administration completed a study to investigate the performance of eight one-coat systems and two control coatings for corrosion protection of highway bridges. Based on prior performance, a three-coat system and a two-coat system were selected as the control coating systems. The performance of all coating systems was evaluated under accelerated laboratory and outdoor exposure conditions. Accelerated testing was performed in the laboratory for 6,840 h. Natural weathering exposure was performed in the outdoor environment for 18 months and at a marine exposure site for 24 months. A calcium sulfonate alkyd coating system was found to perform equally in comparison with the three-coat system; however, curing was a major concern. Regression analysis was used to identify correlations between color, gloss, adhesion strength, and coating defects for one-coat systems.