Asphalt Road Surface Crack Propagation Behavior Analysis

The bearing capacity and usage limit of road were decreased with the appearance of asphalt pavement early crack. The using performance of road was also affect by it. Recently, surface crack which initiated on the top of asphalt pavement and propagated downward attracted more and more attention. Based on fracture mechanics theory, finite element model was established with the commerce FEM software ABAQUS and the propagation behavior of asphalt pavement surface crack was numerically analyzed.Considering frictional contact status between asphalt surface and semi-rigid base, two-dimensional and three-dimensional finite element models were established separately under moving load which was applied by introducing user subroutine. The stress intensity factor was calculated by displacement method and the change law ofstress intensity factor K₁₁ of transverse and longitudinal surface crack varying with theposition of load was analyzed.Through analyzing the calculation result of two-dimensional and three-dimensional models, the main research conclusions were as follows:(1) The effects of pavement parameters such as surface thickness and surface modulus and base modulus on surface crack propagation were discussed. The propagation of surface crack can be mitigated by increasing base modulus. But it was not always favorable for mitigating the propagation of surface crack by increasing surface thickness and surface modulus.(2) The effects of different crack depth and different frictional contact status between layers on surface crack propagation were also analyzed. The results showed that surface crack propagated quickly in early stage, so the rehabilitation and maintenance of surface crack should be done as early as possible. The propagation of surface crack can be effectively mitigated by strengthening the bond degree between layers.(3) The influence of non-uniform distributed load and overloading on surface crack propagation was analyzed. The effect of concave distribution load on surface crack was more than uniform distributed load and convex distribution load. Overloading accelerated the propagation of surface crack.Some theoretical reference was provided for the rational design of semi-rigid asphalt pavement and for the maintenance and rehabilitation of asphalt pavement.