Research on Asphalt Mixture Permanent Deformation by Single Penetration Repeated Shear Test (SPRST)

Abstract:

The problem of pavement rutting is getting worse, which reduces pavements’ life and greatly effects driving safety. Through comparative analysis, a single penetration repeated shear test (SPRST) for a research on asphalt mixture permanent deformation was put forward. Many SPRST tests on different load levels were did with four kinds of most commonly used asphalt mixtures in the upper and middle layer of asphalt pavements. Some conclusions were the followings. (1) The three-stage permanent deformation behavior of asphalt mixtures on loads could be got by SPSFT. (2) The bigger the load was the faster permanent deformation of asphalt mixtures increased and the smaller the shear fatigue life or the flow number were. Large load (≥1.3MPa) made the large deformation with not large load cycles and the mixture broke; but the smaller load (≤1.1MPa) got very slow increase of the deformation, which was stably in the second stage of three-stage permanent deformation and didn’t broke. (3) The asphalt mixtures with bigger shear strength had a greater ability resistance to shear deformation. Mixtures with modified asphalt had a greater ability resistance to shear deformation than with conventional asphalt. (4) Load stress levels had an equivalence to load cycles.