Performance monitoring of field test section to evaluate rutting behavior of different pavement layers

To evaluate the contribution of different pavement layers to rutting failure, a 304-meter-long (1,000 feet) test section was constructed on Interstate 35 near Purcell, Oklahoma. The section was comprised of five layers: two Hot Mix Asphalt (HMA), one aggregate base, one stabilized subgrade, and natural subgrade layers. Rutting was measured on the pavement section for approximately six years. The rutted profiles of the test section were compared with those in National Cooperative Highway Research Program (NCHRP) Report 468. Significant rutting value of 22.04-millimeter (0.868 inch) was observed on the test section. To further investigate, trenches were cut at three selected locations having highest, lowest, and average rutting. It was observed that the HMA layers, more specifically the surface layer, contributed to most of the rutting. Minimal to negligible rutting was observed in the aggregate base, stabilized, and natural subgrade layers. Furthermore, the MEPDG rutting models were calibrated based contribution of each of the layers, and the optimized calibration coefficients were: βr1 = 1.35, βr2 = 1, βr3 = 1.05 for HMA; βGB = 0.05 for aggregate base, and βSG = 0.05 for natural subgrade. Results from this field study provide an insight on the behavior of different pavement layers in addressing rutting problems in future designs.