Bridge Coatings that resist Rust, Bird Poo, and Weather The BorderTransportationSystem will need to stand up to the elements of nature, and to nature itself.  Over the decades the Lead Based Paints once used for protecting bridges has been phased out due to health hazards, and these paints have been replaced with Zinc additive coatings. Feb 1, 2015 High-Performance Steel Bridge Coating Options - There’s more than one way to coat a bridge. BY Robert Kogler and Laura Erickson "Specifically, zinc-rich coating systems eventually became the standard due to their greatly improved performance in salt rich environments. With the continuous pressure on owners to maintain open roads and “dry pavement” at all times in all seasons, the use of deicing chemicals increased the demands on corrosion protection systems nationwide. These factors conspired against the older steel bridges painted with no surface preparation and mediocre paint." "When the use of deicers increased dramatically, these older systems were ill-suited to perform for long periods of time, and the condition of the steel bridge inventory suffered. However, for those structures built or repainted more recently with modern paint systems, performance has dramatically improved. So it is important to note that when considering design options for new or replacement bridges, the historical corrosion protection performance of a “painted steel bridge” in a specific environment will likely not be representative of the improved performance expected from a more modern “high-performance coating system” in the same bridge today" Index of ... Full Article - Click Here   Wisconsin DOT - 2857 Jolly Road, Okemos, MI 48864  {2016} TEP2 AASHTO Transportation System Preservation Technical Services Program "The Wisconsin DOT has published a report summarizing the effectiveness of aesthetic coating systems for steel bridges. Twelve 2-coat, 3-coat, and duplex coating systems were selected and subjected to a series of accelerated weathering and mechanical tests to determine their performance. The performance evaluation was made by considering gloss and color retention, coating discontinuities, rust creepage, and coating adhesion. Surface preparation and coating application procedures were given significant consideration." "The best color and gloss retention were achieved by the 3-coat fluoropolymer systems, but the materials had higher costs. One of the two 2-coat systems performed nearly the same as the 3-coat polyurethane coating systems and the other performed poorly with significant color fading."  "Duplex polyurethane systems showed comparable performance to that of the 3-coat fluoropolymer systems but they performed better than the 3-coat polyurethane systems. This was primarily due to the added corrosion protection provided by the hot dip galvanization. The study found that proper adhesion in a duplex system can be achieved by following appropriate procedures for galvanization and surface preparation. Both duplex powder coated systems tested in this study experienced out-gassing problems during the initial application and did not perform satisfactorily." Index of ... Full Article - Click here