Minimum Thickness Requirements for Asphalt Surface Course and Base Layer in Airfield Pavements

In designing flexible pavements for military airfields, minimum thicknesses of surface and base courses are given in the Unified Facilities Criteria UFC in tabular form based on the aircraft type, traffic area, and base California Bearing Ratio CBR. With the development of larger and heavier aircraft, the minimum thickness requirements were simply adjusted upward through an empirical approach. In this report, the U.S. Army Engineer Research and Development Center ERDC research team proposes a rational methodology for determining minimum thicknesses for airfield pavements. The proposed procedure considers aircraft wheel loads, tire pressure, load repetitions, and the CBR of both base and subbase layers. In addition to presenting the methodology for determining layer minimum thicknesses from a structural standpoint, the manuscript briefly presents an examination of the effects of construction methods and materials on minimum thickness. Construction equipment and asphalt material characteristics directly influence the thickness of asphalt layer that can be constructed and its performance when subjected to traffic and the environment.