Interlayer Shear Strength Theory And Test Of Asphalt Pavement

As the main form of road pavement in China,asphalt pavement has the advantages of smooth surface,comfortable driving,good wear resistance,and easy construction and maintenance,so it is more and more widely used in road application.But due to the late start of highway construction in our country,the relatively slow development and the unsatisfactory traffic control operations and other reasons.This leads to more diseases in the asphalt pavement,among which the inter-layer shear failure performance is particularly prominent.The problem of inter-layer shear failure of asphalt pavement has always been the focus of research at domestic and foreign.However,because of the differences in the natural environment of the roads and the road design concepts and construction methods in different countries,there are certain deficiencies in the study of the shear strength between layers of asphalt pavement.Therefore,the theoretical and experimental research on the inter-layer shear strength of asphalt pavement has very important theoretical and practical significance for the design and construction of asphalt pavement.In this study,the mechanical friction resistance of asphalt pavement was first deduced theoretically based on elastic laminar mechanics,contact mechanics and fractal theory.Then,the theory of surface energy and interface mechanics were used to establish the theoretical model of the bonding strength between the layered material and aggregate of asphalt pavement.In addition,the viscoelasticity theory was used to analyze the shear strength of the inter-layer adhesive layer material.Based on the above three parts of theoretical research,the joint shear strength of asphalt pavement layers was studied and analyzed.Finally,an inter-layer shear test with different gradation combinations and different types of adhesive layers was used for comparative analysis.The theoretical results show that the actual contact area of the asphalt pavement is only a part of the nominal contact area under the conditions of good contact between layers.Among them,the gradation combination type is AC-13/AC-16 with the largest contact area,followed by AC-13/AC-20,AC-16/AC-20.The study shows that the shear strength of the three parts has a great influence on the combined shear strength of the layers.Under the same load,the mechanical friction resistance between layers is greatly affected by the upper and lower grading combinations.When the grading combination type is AC-13/AC-20,the mechanical friction resistance between the layers is the highest,followed by AC-16/AC-20,AC-13/AC-16.Under the condition that the lower grading type and the loading conditions are the same,the adhesive strength of the emulsified asphalt and the underlying layer is the largest,followed by the SBS-modified asphalt and the base asphalt.Under the same loading conditions,the shear strength of SBS-modified asphalt has the largest performance,followed by base asphalt and emulsified asphalt.The experimental results show that the effect of inter-layer grading combination type and material type of the layer on the shear strength between layers tends to be consistent with the theoretical research results.The results show that the loading temperature,loading rate and loading angle have a great influence on the inter-layer shear strength.The inter-layer shear strength gradually decreases,with the rising of the loading temperature and the loading angle.The inter-layer shear strength gradually increases,with the loading rate increases.