Study On Interfacial Mechanical Behavior Of Asphalt Pavement Under Heavy Vehicle Loading

Vehicles are the main loads of the pavement, and the pavement is damaged due to the long-term effects of them. Because the vehicle's velocities are higher and the loads of vehicles are heavier than before, the dynamic loads of vehicles are being increased. The interlayers of pavement can not be completely continuous due to different materials of pavement, road construction technology and other factors. So the stress variation in the pavement is complex. The interfacial mechanical behavior of asphalt pavement under heavy vehicle loading is studied in the paper.A 3-axle vehicle vehicle model and a 4-axle vehicle model are established base on the character of the vehicle travel on the highway. The additional dynamic load and dynamic load coefficent of the 3-axle vehicle and the 4-axle vehicle are simulated with MATLAB. The effects of road parameters, vehicle velocity and mechanism parameters of vehicles on the dynamic load coefficent are studied. A vehicle speed prediction model on the uphill section is established base on the vehicle dynamics equation. The influences of the slope, slope length, vehicle load and the choice of shifting speed are studied.The bond behavior of the interlayer is tested with the shear device designed by the research group. The shear strength and its variation of the interlayer are obtained.The contact status of the interlayer are simulated as continuous or bond, and the dynamic responses are calculated. The normal stress and shear stress in the pavement are studied under the different contact conditions. When the interlayer is bond, the longitudinal and transverse normal stresses of the pavement are increased, and the positions of the maximum of longitudinal and transverse shear stress in the pavement are changed.The influences of the horizontal force, tire contact pressure and temperature are studied. The normal stress and the shear stress in the pavement are increased when the horizontal force and the tire contact pressure are increased. The normal strain and the shear stress are increased with the temperature.The asphalt is a typical viscoelastic material. The Burgers model is used to simulate the properties of it. A pavement structure model under moving load for dynamic response analysis is established through the moving load subroutine. The influence of vehicle speed is analysised. The normal stress and the shear stress in the pavement are decreased when vehicle speed is increased.