ABSTRACT
Alaska’s Parks Highway is an asphalt paved and predominantly two-lane roadway that extends over 323 miles (520 km), and links its two largest cities, Anchorage and Fairbanks. The Alaska Department of Transportation and Public Facilities (DOT&PF) places annual springtime load restrictions on this primary haul route. To investigate the possibility of structurally upgrading the roadway to eliminate the springtime load restrictions, the DOT&PF assessed the bearing capacity of this flexible pavement by performing Falling Weight Deflectometer (FWD) testing along the highway after the thaw period, in conjunction with continuous Ground Penetrating Radar (GPR) measurements. In addition, periodic FWD testing was carried out weekly during springtime at three temperature data probe sites along the highway to assess springtime bearing capacity and develop seasonal adjustment factors for the different pavement layers. Using a 20-year design period, this study assessed bearing capacity and quantified the required structural overlay with the currently imposed springtime weight restrictions and the additional pavement damage due to the springtime load restrictions removal. Based on the assumptions made in this study, results showed that two to six inches (5 to 15 cm) of overlay may be required and the additional overlay needed to remove the weight restrictions is minimal.
