The Interface Model Research Of Typical Asphalt Pavement Structure In Central-south Area

Pavement structures are often layered paved. According to different functions and layers of materials, pavement structure can be divided into the surface layer of the base and subgrade. Depending on the specific circumstances, the surface layer can be divided into upper layer, the surface layer and the bottom layer. Grassroots including upper grassroots, the lower grassroots, subbase or cushion and so on. Interface between any two layers called interlayer interface.Our current pavement design theory is based on the multi-layer elastic system theory, and assuming that the interface between layers is completely continuous.But in actual road, interlayer contact state is more complex interface. Neither is completely continuous, it is not in a fully sliding state, which makes the mechanical response generated by the actual pavement structure under vehicle load have a big difference with the mechanical response of the ideal state. On the other hand, the existing researches found that pavement diseases such as slip cracks, rutting, push and hold bag, etc., seriously affect road performance; and interlayer adhesion state of deterioration is one of the main factors, leading to the road surface slip crack, producing pavement disease faster.Contact condition between the asphalt surface layers plays an important role on the structure behavior and service life. Therefore, finding out the road interlayer combination status is very important. Interlayer interface model can be used to describe the combination between the asphalt pavement structure layer, and with the specific formula to describe the relationship between the force and displacement.Directly having access to the contact condition of asphalt concrete layer interface is difficult.Getting it can only choose simulation method and through laboratory test. The usual way is: getting on-site retrieved core samples or laboratory specimen on shear test, and then by means of data analysis, we can get some conditions of interlayer interface model.At present, the existing interface test model is based on three parameters, namely the interface modulus K, interlaminar largest shear strength Smax, friction coefficient mu, to describe the state of interface adhesion between the actual road. Due to differences in the material, and loading conditions, the test temperature, test equipment, and other factors, these parameters or conclusion does not have the versatility.This paper based on the domestic and foreign relevant test methods and results, using the Goodman model to describe the relationship between force and displacement of the asphalt surface layer interface under certain load condition. And on the basis of materials of the central south region and the condition of temperature, choosing different test temperature, different dosage of tack coat and different type of tack coat, the paper use the the laboratory UTM multi-function testing machine and self developed fixture to carry on direct shear test of the bond strength between the layers, and then through the method of regression analysis of experimental data, the basic rules of shear strength of the asphalt mixture specimen under the condition of various factors is obtained. This study found that: different temperature, different types and amount of tack coat have a greater influence on the interface test model. In the case of the same type and amount of tack coat, as the temperature rises, the interface reactionr modulus declining, decreasing the maximum shear strength.