An Experimental Study On Mechanical Behaviors Of Stone-Asphalt Interface Subjected To Shear Loading

Because of its high strength,low noise,simple forming and maintenance,and stable and comfortable driving,asphalt concrete has been widely used in road engineering.As everyone knows,the early damage of asphalt concrete pavement is very serious in China,peeling,loose,emerge in an endless stream pits and other diseases,greatly reduces the life of asphalt concrete pavement and driving comfort.A large number of researchers generally believe that the asphalt and aggregate interfacial cohesive strength and adhesion strength are the key factor for the formation of the asphalt concrete,and has a direct impact on various asphalt concrete performance.The interface between asphalt and aggregate is the weak link of asphalt concrete structure,and various damage forms are often originated from the interfacial damage.The mechanical properties of the interface are key factors determining the performance of asphalt concrete.Therefore,it is very important to study the interfacial mechanical behavior of the interface,which is important to the design,and maintenance of asphalt concrete.This research begins from the basic structure of asphalt concrete,based on former results of the existing asphalt mixture shear mechanical behavior and interface mechanical behavior,study cohesive characteristics and failure mechanism of interface.In order to study the interface shear strength,a shear fixture is designed,with universal testing machine and environment box.After test,a shear stress-displacement curve can be obtained.It is found that the interfacial failure mode is hybrid cohesive-adhesive failure,while the pure adhesion failure and cohesive failure are seldom occurred.It is also found that under the same experimental conditions,the shear stress displacement curves of asphalt aggregate interface show different patterns.Then,the influence of different experimental conditions was analyzed.The results show that the aggregate surface roughness,forming load and test loading rate have a significant impact on the test results,and these factors on different models have different effects on the force displacement curve.The peak stress,corresponding displacement and shear stiffness index are used to describe the stress-displacement curves.In addition,it is found that the second peak of the double-peak curves shows a linear relationship with its displacement.