Mechanistic-Empirical Framework for Development and Verification of Rutting Test Criteria for Flexible Airfield Pavements

Abstract

This study aims to establish a comprehensive mechanistic framework to refine the current Federal Aviation Administration (FAA) specification of the Asphalt Pavement Analyzer (APA) test method at 250 pounds per square inch (psi) tire pressure and 250 lb wheel load, for different aircraft load levels and speeds. The criteria adjustments were based on airfield pavement mechanistic responses coupled with rutting performance models, developed from the repeated load triaxial (RLT) test conducted on airfield asphalt mixtures. The first step in the framework involved numerical modeling using 3D-Move to evaluate airfield pavement responses under different loading conditions. A sensitivity analysis was performed based on 3D-Move responses including three temperatures, three speeds, and five aircraft load levels. The state of stresses generated by 3D-Move was utilized to determine the range of deviatoric (σ _d ) and confining (σ _c ) stresses that covers different airfield loading conditions. Subsequently, the RLT test was performed under three selected sets of σ _d and σ _c . This effort aims to quantify the sensitivity of the calculated rut depth to speed, temperature, and gross aircraft weight using the laboratory-developed, mix-specific performance models. Based on the APA 250 psi/250 lb test thresholds refined from the FAA Advisory Circular 150/5370-10H, new test criteria were established for different rutting mechanical tests, including APA 100 psi/100 lb, the Hamburg Wheel Track Test, High Temperature Indirect Tensile Test, and Ideal Rutting Test. As a preliminary verification of the recommended criteria, field cores from airfield pavements with varying field rutting performance were evaluated using laboratory mechanical tests. The test data was then compared against the refined test thresholds to ensure that the proposed test criteria can effectively identify airfield mixtures with poor field performance in rutting.