Study On The Shear Mechanical Behavior Of Asphalt Aggregate Interface Under The Synergistic Effect Of Temperature And Asphalt Film Thickness

Asphalt pavement is widely used in the road industry because of its good road performance.The performance of asphalt pavement is not only related to the asphalt mixture itself,but also to the external environment such as temperature,water environment and external load.Under the combined effect of these external and internal factors,asphalt pavement will produce permanent deformation,which will lead to pavement cracks,ruts,pits and other diseases.The formation of pavement diseases starts from the interface between asphalt and aggregate,so it is of great significance to study the performance of the interface between asphalt and aggregate for improving the performance of asphalt pavement.In this paper,the shear test of asphalt aggregate is designed,and the shear mechanical properties of interface phase of asphalt aggregate under the conditions of temperature and asphalt film thickness are discussed.The main contents are as follows:(1)The shear stress displacement curves of asphalt aggregate interface under different temperature and thickness of asphalt membrane are obtained;(2)The influence of temperature and asphalt film thickness on the shear mechanical properties of asphalt aggregate interface is analyzed;(3)The regional probability map of double peak shear curve of asphalt aggregate interface under the synergistic action of temperature and asphalt film thickness is obtained;(4)The influence of temperature and asphalt film thickness on the shear failure fracture energy of asphalt aggregate interface is analyzed.The results show that:The single peak shear strength of asphalt aggregate interface changes with the temperature and the thickness of asphalt film.With the increase of temperature,the shear strength of single wave peak decreases;with the increase of asphalt film thickness,the shear strength of single wave peak decreases.The results show that the temperature and the thickness of asphalt film have a significant effect on the probability of the occurrence of the double peak.In a certain temperature range(15 ?-35 ?)and a certain asphalt film thickness range(23 ?-219 ?),there will be a double peak curve.The probability and range of the double peak vary with the temperature and the thickness of asphalt film,and the probability is between 10% and 40%.Temperature affects the properties of asphalt aggregate interface by affecting the properties of asphalt and the tension between asphalt and aggregate surface.The thickness of asphalt membranedetermines the content of free asphalt and structural asphalt in asphalt membrane,thus affecting the properties of asphalt aggregate interface.One of the reasons for the double peak is that when the thickness and temperature of the asphalt film are appropriate,adhesion slip and cohesion may occur.When the thickness and temperature of the asphalt film are thin and low,the probability of adhesion slip is high;when the thickness and temperature of the asphalt film are thick,the probability of adhesion slip is high;when adhesion slip and cohesion slip occur at the same time,they will occur double peaks.Finally,the shear failure fracture energy of asphalt aggregate decreases with the increase of temperature,and increases with the increase of asphalt film thickness.The change of shear failure energy is related to the viscoelasticity of asphalt material.