Abstract:

Rutting in asphalt airfield pavements can be a significant problem due to the increasing gross aircraft weight (GAW) and extremely high tire pressures associated with these aircraft. The generated high stresses and strains can reach significant distances below the pavement surface, impacting deeper asphalt layers previously not affected by earlier aircraft of lower weight and tire pressures. To mitigate the potential for rutting of asphalt mixtures, the Federal Aviation Administration (FAA) conducted a research study to evaluate and recommend potential changes to the current FAA P-401/P-403 and P-404 asphalt specifications to help improve the rutting resistance of the asphalt mixtures for different GAW groupings. An extensive literature review and a parametric study were used to determine critical parameters that influence the rutting potential of airfield asphalt mixtures. Proposed changes were selected to minimize detrimentally impacting the long-term cracking performance of the asphalt airfield mixes. As a result, recommendations were provided to change the following asphalt mixture characteristics for different GAW groupings: aggregate angularity criteria for fine and coarse aggregates, asphalt binder grade selection, and inclusion of and modification to asphalt mixture performance testing. Further validation testing using a controlled heavy-vehicle simulator and field test sections are recommended to validate the proposed recommendations.