Debonding in Airfield Pavement Hot Mix Asphalt Layers

Pavement distresses are external indicators of pavement deterioration caused by loading, environmental factors, construction deficiencies, or combinations thereof. The Hot Mix Asphalt (HMA) design for commercial airports in United States of America (USA) is performed as per Federal Aviation Administration (FAA) Advisory Circular AC 150/5370-10G “Standards for Specifying Construction of Airports”, Item P401—Plant Mix Bituminous Pavements (2014). According to FAA study “Operational Life of Airport Pavements”, pavements that meet FAA standards and specification (for design, and construction) generally performed well over their design life. However, recently cases of debonding and slippage have been observed at airports in USA, and other countries. This distress was also observed in the full-scale accelerated pavement tests during flexible pavement construction cycles 1 and 3 at the FAA’s National Airport Pavement Test Facility (NAPTF) and was attributed to tack coat and environmental factors. Asphalt strain gages were installed at the top of milled HMA surface and bottom of HMA overlay at Runway 4R-22L at Newark Liberty International airport (EWR) to study the debonding and slippage distress. Sensor responses were used to detect the onset of debonding and subsequent slippage in the HMA overlay. This paper summarizes the results from two case studies—HMA behavior under full-scale accelerated pavement tests at NAPTF, and the pavement instrumentation project at EWR airport.