Experimental Study On Mechanical Properties Of Asphalt Mixture Under Triaxial Torsional Shear

Nowadays,pavement diseases seriously affect the service life of asphalt mixture pavement,and rutting is the most common form of disease in the pavement.Rutting is actually caused by the accumulation of irreversible deformation generated by the pavement,and the lack of shear resistance of the pavement is the accumulation of the pavement main cause of deformation.Therefore,this paper studies the shear mechanical properties of asphalt mixture through torsion shear test which can control the magnitude of shear stress.This article first introduces the traditional shear test methods of asphalt mixtures commonly used at home and abroad,and formulates the test plan of this article.Through the pure torsion shear test and triaxial torsion shear test of the asphalt mixture specimens obtained by drilling cores,the torsional shear mechanical properties of the asphalt mixture specimens under different conditions of temperature,loading rate and confining pressure are obtained parameter and analyze the law.In the pure torsion shear test,a total of 3 test temperatures and8 loading rate conditions were set,and a total of 3 test temperatures and 4 confining pressure conditions were set for the triaxial torsion shear test.The raw data are processed to obtain the torsional failure strength,shear modulus,maximum strain,elastic deformation zone ratio and strain energy during the torsion process of the asphalt mixture.And analyze the law of parameter changes with test factors and the relationship between pure torsion shear test and triaxial torsion shear test.Through the pure torsion shear and triaxial torsion shear test results,conclusions are drawn:(1)In the pure torsion shear test,the failure strength,shear modulus and strain energy increase linearly with the increase of the loading rate,and the overall The above decreases exponentially with the increase of temperature.(2)The loading rate and temperature have no obvious influence on the maximum strain and the ratio of elastic deformation zone.Only under the condition of 40℃,the ratio of elastic deformation zone gradually increases with the increase of the loading rate.(3)In the triaxial torsion shear test,the damage strength and shear modulus of the asphalt mixture increase with the increase of the confining pressure,Under the condition of 60℃,the failure strength first increases and then decreases with the increase of confining pressure.(4)The confining pressure has no obvious influence on the maximum strain,the ratio of elastic deformation zone,and the strain energy.