Early-Life Permanent Deformation Characteristics of High-Strength Subgrade Full-Scale Test Pavements

The National Airport Pavement Test Facility (NAPTF) is a state-of-the-art full-scale test facility operated by the U.S. Federal Aviation Administration (FAA). The NAPTF is located at the William J. Hughes Technical Center near Atlantic City, New Jersey and it provides high quality, accelerated test data from rigid and flexible pavements subjected to simulated aircraft traffic. During the first construction cycle, the fully enclosed instrumented test track consisted of three 91.4-m (300-ft) long pavement sections with different subgrade strengths (low, medium, and high). Each subgrade had two flexible test items and one rigid test item constructed on it. Two gear configurations, a six-wheel tridem landing gear (Boeing 777) in one lane and a four-wheel dual-tandem landing gear (Boeing 747) in the other lane were tested simultaneously. Transverse surface profile (TSP) measurements were made at regular intervals to monitor pavement rutting performance. Previous research focused on analyzing the extensive data available for the low-strength and medium-strength flexible test sections. In this study, the early-life permanent deformation characteristics of high-strength flexible test sections were studied using the initial rutting data acquired at the NAPTF. The Power model and the Rutting Rate model were used to characterize the rutting trends. Based on the study findings, it may be concluded that both the Boeing 777 and Boeing 747 gear trafficking at 20.4-ton (45-kip) wheel load magnitude will not impose severe stresses on airfield flexible pavements with high-strength subgrade even with minimal asphalt concrete surface and base layer thicknesses. More full-scale test data are needed to verify the findings.