Mechanistic-empirical evaluation of airfield test pavements

The impact of new-generation aircraft (NGA) such as the Boeing 777 and Airbus A380 on airfield pavement performance is of serious concern to airfield authorities worldwide. Recognising the need to develop advanced pavement design procedures based on sound theoretical principles, and with models verified from appropriate full-scale NGA test data, the Federal Aviation Administration constructed the National Airport Pavement Test Facility (NAPTF). In this paper, a mechanistic-based approach is presented to predict the allowable six-wheel and four-wheel NGA gear passes for airfield flexible pavements based on full-scale traffic test results from the NAPTF. A finite-element pavement structural model that can account for the non-linear stress-dependent behaviour of pavement geomaterials was used to compute the mechanistic responses of NAPTF test sections. Both the subgrade deviator stress and subgrade stress ratio were found to be good estimators of airfield pavement rutting performance. Although the results are applicable specifically to the six-wheel and four-wheel NGA gears used at NAPTF, the method can easily be extended to any prototype NGA gear loading with additional data from such full-scale traffic tests.