Accelerated Performance Testing of Coating Systems for Bridges--Kentucky Highway Investigative Task No. 47

KYTC paint personnel seek to obtain coatings perfonnance tests on a variety of coatings systems for current and future use on Kentucky bridges. These coatings systems include proprietary coatings offered by manufacturers, low-VOC coatings which may address future environmental restrictions, ultra-high perfonnance systems that promise greater durability, and special coatings that may provide specific benefits for certain projects (i.e., rapid deployment coatings for use on overpass bridges over high ADT roadways). In the past, KTC has perfonned some of those tests as subtasks in various KHITs and SPR studies. This proposed KHIT is intended to provide KYTC with test data for coatings identified by KYTC paint personnel. KYTC Division of Operations would identify and obtain samples of coatings systems of interest to KYTC paint personnel. The KYTC Division of Materials would conduct preliminary tests on sample coatings to characterize them and ensure that they confonned to manufacturer product data sheets. After testing, samples of the coatings would be obtained by KTC. KTC personnel will prepare steel test panels for painting and apply the coatings systems in the KTC spray booth. Companion panels will be coated with the KYTC standard specification polyurethane coatings system. During and after the coatings application process, KTC technicians will measure the coating thicknesses and detennine the suitability of the coated panels for representative perfonnance testing of the coatings. After curing and preparation for performance testing, 5 panels of the test coating system and 5 panels with the KYTC standard system will be tested for accelerated weathering (QUV and freeze-thaw) and accelerated corrosion (Prohesion). Those tests will be perfonned in 168-hour (1 week) time blocks in each chamber in the order: QUV, Prohesion & freeze-thaw. After each 1,008 hours of tests (6 weeks), the test panels will be removed from the test cycle in evaluated for rusting, scribe undercutting, blistering, gloss retention (where applicable) and color stability (where ~pplicable). The panels will be photographed and the results reported to KYTC paint personnel at each 1,008 evaluation point. The testing will run for 5,040 hrs (30 weeks). KTC personnel have developed 6 Standard Operating Procedures that detail the work to be perfonned from receipt of the coatings systems through testing, evaluation and reporting (including timelines for report submittal). Those have been reviewed by KYTC paint personnel and revised. The revised SOPs will serve as the basis for all work conducted under this KHIT.