Mechanism Analysis of Asphalt Pavement Slippage Failure at High-Speed Exits of Airports

Abstract

Slippage failure has been observed at high-speed exits of airfield pavements, which may be caused by the instability of the asphalt mixture or interface delamination. This paper investigates the slippage failure mechanism using an integration of laboratory characterization and mechanistic modeling. First, laboratory tests were conducted to measure shear strength parameters of asphalt bulk mix and layer interface at different temperatures. Second, advanced finite element models were developed to calculate airfield pavement responses under moving aircraft tire loading. Finally, the multi-axial stress state criterion was used to quantify shear failure potential under the combined loading of normal stresses and shear stresses, respectively, at pavement near-surface and layer interface under different analysis scenarios. Shear strength of asphalt mixture and interface bonding varied with mix designs and decreased significantly with temperature increase, while the stress states in airfield pavement were more affected by the aircraft loading condition. It was found that shear stress ratios at the interface are greater than those in asphalt surface layer, indicating that there may be a higher possibility of shear failure through interface delamination as compared with plastic deformation in the asphalt surface layer. The analysis findings will help develop materials and/or construction specifications to prevent slippage failure at high-speed exits of airports.