Research On Skeleton Behavior Of OGFC Pavement And Interlayer Bonding Performance Considering Interface Structural Characteristics

Open-graded Friction Course(OGFC)provides an efficient,safe and environmentally friendly option for the construction and maintenance of asphalt pavement in China.Under the coupling effects of loading and environment,OGFC pavement has problems such as early failure and insufficient durability.It is of great significance to clarify the skeleton behavior and interlaminar cracking behavior of OGFC pavement for the mechanical durability design of OGFC pavement.In this paper,discrete element method,3D optical scanning,CT scanning and laboratory tests were used to explore the skeleton behavior and interlayer bonding performance of OGFC pavement.The specific work includes:(1)Based on the discrete element method,four OGFC gradations and one dense gradation were selected to carry out cyclic ballast and virtual penetration tests;The corresponding relationship between aggregate gradation and skeleton behavior was analyzed and established according to the results of compacted skeleton void ratio,strong and weak contact mesh and penetration strength.(2)Seven key parameters,such as average surface roughness,skewness and fractal dimension etc.,were measured by using 3d optical scanning and numerical calculation techniques to accurately characterize the interlayer surface structure.(3)Using CT scanning and image digital processing technology,the three-dimensional reconstruction of the combined structure of the OGFC and the underlying layer was achieved,and the pore structure characteristics of OGFC and the migration behavior of the tack coat were obtained.(4)Based on the theory of fracture mechanics,a three-point bending test was designed to obtain the relevant parameters of mode I fracture of the OGFC-underlying composite,and the relationship between interlayer bonding performance and interface parameters was built.