Volume 35, Issue 4 (July 2007)
Pavement Deformation Characteristics under
Full-scale traffic testing was conducted at the Federal Aviation Administration’s National Airport Pavement Test Facility (NAPTF) using Boeing 777 (B777) and Boeing 747 (B747) simulated test gears on flexible pavement test sections until they were deemed to be failed. An inertial profiling device was used to measure the transverse surface profiles at frequent intervals during NAPTF trafficking. Results from the multi-depth deflectometers (MDDs) installed within the test pavements were used to monitor the cumulative permanent deformations. The MDD results showed that the sequence of repetitive aircraft gear loads with different wander positions used at NAPTF led to contractive/dilative permanent deformation behavior, especially in the unbound pavement layers. The magnitudes of MDD residual responses were dependent on the position of the traffic gear, the previous traffic history, and the direction of traffic (east/west). These results suggest that reliable prediction of permanent deformation in airport flexible pavements is a highly challenging task owing to the complexities arising from aircraft loading sequence, gear offset and gear offset sequence, and climatic conditions.