Study On Creep Characteristics Of Double-layer Combination Asphalt Mixture In High Temperature Area

Asphalt mixture is a typical viscoelastic material.The performance of asphalt pavement is affected by temperature and load.With the rise of global temperature,the typical high temperature diseases mainly rutting occur in asphalt pavement.Based on Shaoguan engineering project,this paper focuses on the creep characteristics of double-layer composite asphalt mixture,and discusses the influence of different temperature,stress and material combination factors on the mechanical properties of composite asphalt mixture.Based on the basic creep theory of asphalt concrete,the related concepts,mechanism and main theories of creep are expounded,and studies the creep behavior of double-layer composite asphalt mixture under load and temperature based on the analysis of temperature field of asphalt pavement in high temperature area.In view of the research on temperature field of asphalt pavement in high temperature area,this paper mainly analyzes the temperature situation of typical cities in Guangdong Province,and further divides the temperature of typical cities in Guangdong Province in detail on the basis of the division specified in"technical code for construction of highway asphalt pavement".Embeds temperature sensors in the asphalt pavement site to collect the temperature data at different positions in the pavement structure,and analyzes the asphalt concrete pavement structure the internal temperature of the structure changes with time.On the basis of ensuring the quality of raw materials,the reasonable gradation of asphalt mixture and the best asphalt content are determined.The rutting test and uniaxial creep test are carried out for asphalt mixture with different anti rutting materials.The high temperature creep properties of AC-13C asphalt mixture and AC-20C asphalt mixture with different anti rutting materials are compared and analyzed,and the double-layer asphalt mixture with different combination forms is comprehensively compared In this paper,the creep characteristics of composite asphalt mixture are analyzed by using the improved Burgers model,"four unit,five parameter"model,and the creep characteristics of single-layer asphalt mixture and double-layer composite asphalt mixture are compared.Finally,four intersections are selected for paving,and the indoor test is used to analyze the test core samples,and the rutting depth of asphalt pavement after operation is investigated.The results show that:The creep performance of asphalt mixture increases with the decrease of residual strain ratio(residual deformation,cumulative deformation),and decreases with the decrease of stiffness modulus.For the same kind of double-layer composite material,under the same temperature condition,with the increase of stress level,the creep performance of composite material gradually decreases;under the same stress condition,with the increase of temperature level,the creep performance of composite material gradually decreases;temperature and stress will affect the creep performance of double-layer composite asphalt mixture,and the effect of temperature on the creep performance of double-layer composite is more sensitive.The creep performance of double-layer composite material is better than that of single-layer AC-13C asphalt mixture and AC-20C asphalt mixture.The"four unit,five parameter"model is used to fit the creep results of single and double layer asphalt mixture.The test data show good correlation with the fitting curve.The fitting result R~2 of single layer asphalt mixture is more than 0.97,and that of double layer composite material is more than 0.92.It shows that the"four unit,five parameter"model can describe single layer and double layer composite asphalt creep characteristics of mixture.