Study On High-temperature Shear Resistance Of GAC-16 Asphalt Mixture

Rutting of asphalt pavement is caused by lack of asphalt mixture at high temperature shear strength in recent years,with the improvement of intensive gradation of asphalt mixture GAC asphalt mixture,has been widely used in China's hot regions,and showed good rutting resistance,effectively reduce the early damage of new asphalt pavement rutting the phenomenon,this paper takes GAC-16 asphalt mixture as the research object,the high temperature shear performance.Firstly,the shear stress and rut formation mechanism of asphalt pavement structure are analyzed,and then the high temperature shear resistance of asphalt mixture is studied from two aspects of asphalt mixture and asphalt mixture.In the aspect of asphalt mortar,the rheological properties of the asphalt mortar under different temperatures,different types of asphalt and the ratio of different powder and glue were studied by DSR dynamic rheological shear apparatus.The change of phase angle and rutting factor of each slurry under high temperature was analyzed.In the aspect of asphalt mixture,the indirect tensile test and unconfined compression test were carried out on the standard Marshall test specimen of asphalt mixture by universal test machine.The shear strength parameters of asphalt mixture,cohesion C and internal friction angle,were calculated.The influence of mixture gradation,oil stone ratio and asphalt type on the test results was analyzed.On this basis,the rutting test of the corresponding asphalt mixture is carried out,and the correlation between dynamic stability and cohesion C and internal friction angle is analyzed.The study found that,the shear stress is mainly distributed on the asphalt pavement and the middle layer structure.The main reason for the flow type rutting is the insufficient shear strength of the asphalt surface material at high temperature.Compared with matrix bitumen,the phase angle of the modified asphalt is smaller and the resistance to permanent deformation is stronger.In the range of research,the anti rutting factor of asphalt mortar increases exponentially with the increase of the powder binder ratio,and decreases exponentially with the increase of temperature.Cohesion C has a good correlation with the splitting strength and dynamic stability of the mixture,and the cohesion is mainly related to the type of asphalt.The cohesion of the mixture,the splitting strength and the shear strength can be improved by the use of the cohesive modified asphalt.There is a certain correlation between the internal friction angle and the compressive strength of the asphalt mixture,and there is no direct correlation with the dynamic stability.The internal friction angle is mainly dependent on the gradation of the mineral material,and it is also influenced by the type and the amount of the asphalt.