Variable Subbase Thickness Effects on Rutting Performance of NAPTF Flexible Pavements Subjected to MWHGL Traffic

Abstract

The reconstructed flexible pavement test sections at the National Airport Pavement Test Facility (NAPTF) consisted of similar Asphalt Concrete (AC) and granular base thicknesses, but variable granular subbase thicknesses. These sections were simultaneously trafficked by 6-wheel and 4-wheel landing gears. Rut depth measurements were made at frequent intervals. The development of rut depths under trafficking were characterized using the Power model and the Pavement Surface Rutting Rate (RR) model. For similar number of load repetitions, test sections with reduced subbase thicknesses yielded larger rut depths. The Power model coefficient “A” is helpful in quantifying the rutting potential and early-life rut depth development. The final rut depths varied between 4 to 8 inches. The NAPTF 1-inch surface upheaval failure criteria did not yield consistent rut depths. A functional failure criterion is suggested.