Currently, protective coatings applied to new steel bridges have anticipated service lives of approximately 30 years; for maintenance coatings, this figure is 20 years. With state highway agencies seeing their maintenance funding stretched thin to maintain infrastructure, it is critical to extend the service lives of coatings for as long as possible. Coatings manufacturers possess the knowledge and technologies required to produce new coatings which significantly outperform what they currently provide to public agencies, however, they their isn't much of a market for those items absent empirical testing. The current market environment for structural coatings is commodity-based and often emphasizes low up front cost over coating performance / longevity. The additional upfront cost of a high-performance coating system is could be more than offset by a significant reduction in life cycle costs over the life of the coatings project. If coating project specifiers had stratified lists of approved materials which recognized the cost differentials for better performing materials, longer service lives of protective coating systems could be achieved at advantageous life cycle costs. Test methods currently used to evaluate protective coatings — typically, ASTM D5894 for structural steel coatings — do not stress the coatings sufficiently to differentiate between acceptable and high-performance coatings materials within a reasonable timeframe. Current test protocols call for 5,000 hours of accelerated weathering/corrosion and approximately 40 weeks to complete. After 5,000 hours of weathering/corrosion, poor performing coatings can be identified, but it is not possible to reliably differentiate better performing coatings from ones that are merely acceptable. It is impractical to conduct coatings performance tests that last for a longer period than those currently used.

This project will develop accelerated performance testing protocols, including evaluation methods, for high-performance coatings for structural steel. It will also develop equipment to execute the new testing protocols and undertake comparison testing of the current and new performance testing protocols. Commitment level is $25,000/yr. for 3 years.

Phase 1: Assess the current state of the practice and expertise. Recommend new test protocols to address the objective of accelerated weathering/corrosion of steel coatings. Phase 2: Develop modified or new test protocols and equipment. Phase 3: Proof of concept testing and reporting.