Research On Application Of Pure Torsional Shear Test On The Shear Performance Evaluation Of Asphalt Mixture

Rutting, shoving, wave, uplift of asphalt pavement is always caused by lack of shear strength of asphalt mixture at high temperature. In this paper, use a new test method to evaluate the shear performance of asphalt mixture which based on Moore-Kulun strength theory.This paper first points out the importance of the shear strength of asphalt mixture, concluded the deficiency of the existing evaluation of shear strength test method of asphalt mixture, introduce the equipment and the method of torsional shear test in detail. This test using the prism of asphalt mixture material of square section specimen, The specimen appear torsion failure by applied pure torsion in the two ends of the test piece, corresponding analysis the torsion stress condition of asphalt mixture under high temperature.Asphalt mixture failure in a pure shear stress condition by torsional shear test, this kind of simple stress state performance a center stress circle in the Mohr-Coulomb plane. This paper use torsional shear failure test, uniaxial compressive failure tests and direct tensile failure test this three kinds of test methods, get the failure strength of five kinds asphalt mixture under different loading conditions. According to Mohr-Coulomb strength theory, By any of these two tests can get the shear strength parameters of asphalt mixture, Theoretically the three kinds of test results can be verified each other.At last, analysis each kind of test data and draw the force-displacement curve, Can visually see the stability of the results. Torsional shear failure test and uniaxial compression failure test of asphalt mixture is simple in operation, the data obtained were relatively stable; In contrast the accuracy of direct tensile test results are hard to control, So it’s relatively reliable to use the results of torsional shear failure test and uniaxial compression failure test to obtain the shear strength parameters of asphalt mixture.