Accelerated Weathering of Traffic Control Materials by Laboratory Testing

US Transportation Collection2020PDFTech ReportElsafty, AdelHsuan, Yick (Grace)University of North FloridaFlorida. Department of TransportationUniversity of North FloridaFloridaUnited StatesAccelerated testsCoatingsLaboratory testsRetroreflectivitySunlightTraffic control devicesWeatheringUltraviolet radiationLaboratory Accelerated TestSunlight DegradationOutdoor ExposureBE717Final Report, February 2019 - February 2020This project was undertaken to identify the appropriate accelerated laboratory testing procedures and conditions for predicting weathering deterioration of coating materials for steel structures and retroreflective sign sheeting materials for traffic control. The current standard test methods specified by state transportation departments, FHWA, and manufacturers were reviewed. The effects of test parameters, including irradiance, temperature, moisture, chloride ion concentration, and exposure duration, were discussed. The correlation of various laboratory accelerated test methods with outdoor testing were evaluated and analyzed. The acceleration factors of different accelerated laboratory tests were calculated using the corresponding published test data. Test protocols for the coating materials and sign sheeting materials were recommended. For the coating materials, test conditions of ASTM D5894 were modified by increasing the UV irradiance, temperature, chloride ion concentration, and test duration to shorten the testing time to 10% of the outdoor exposure. For the sign sheeting materials, irradiance levels during xenon light-on periods of the test procedure according to ASTM D7869 were increased to accomplish the testing time of 16% of the outdoor testing duration.120