Evaluation of Retro-Reflective Beads to Increase Airport Surface Marking Conspicuity

摘要

Manufacturers have postulated that retro-reflective beads that have a higher index of refraction increase the conspicuity of paint markings and, thus, would aid in the prevention of runway incursions. The purpose of this project was to determine the adequacy of various types of retro-reflective beads that are used to increase the conspicuity of painted markings when applied to airport surface markings. The increased conspicuity could assist in the prevention of runway incursions. Five types of retro-reflective beads were evaluated: three are currently approved by the Federal Aviation Administration (FAA) for use on airfield markings, as indicated in FAA Advisory Circular 150/5370-10D and two are the newly proposed retro-reflective beads. The beads were applied to standard paint on three types of airport pavement surfaces: hot-mix asphalt (HMA), Portland cement concrete (PCC), and aged HMA. Three test sites were chosen. Test Site One was located inside the FAA William J. Hughes Technical Center National Airport Pavement Test Facility on new HMA. Test Site Two was located at the FAA William J. Hughes Technical Center Aircraft Parking Apron on aged PCC surface. Test Site Three was on Taxiway Bravo at the Atlantic City International Airport, which is comprised of aged HMA. This evaluation covered a 1-year period starting in August 2008. This research validates previous research performed on Type I, Type III, and Type IV retro-reflective beads. No previous research was performed on the two newly proposed retro-reflective beads. The initial application tests concerning coverage, water, and pull-off strength were deemed successful. On new HMA, the test marking with Type IV retro-reflective beads remained conspicuous for the longest period of time. Type I, Type III, and Manufacturer B retro-reflective beads remained conspicuous for approximately half that time, and Manufacturer A for approximately one-quarter of the time. All the approved retro-reflective beads proved suitable for use on aged HMA and aged PCC over a 1-year period. The proposed retro-reflective beads from Manufacturer A and Manufacturer B also proved suitable for use on aged HMA and aged PCC.