Shear resistance properties of TPS modified bitumen binders and asphalt mixtures

Abstract

Shear resistance properties of the virgin bitumen and modified bitumen binders with Tafpack Super (TPS) modifier and SBS modified bitumen were discussed. Dynamic shear rheometer (DSR) was used to measure the laboratory creep data for these binders over a wide range of constant shear stresses at 20 °C to characterize the shear creep behaviors of all kinds of asphalt binders, and the rutting test system was used to investigate the permanent deformation of porous asphalt mixtures using the above bitumen binders for a fixed compressive stress. The shear strain rate and shear creep modulus were used to characterize the shear creep behavior of the TPS modified bitumen, and the rutting test results were used to show the consistency of porous asphalt mixtures with the bitumen binders. Results indicate that a distinction of shear creep strain can be made among different contents of TPS modified bitumen at the same stress level, where the shear creep strain-time response curve of the SBS modified bitumen binder is between the curves of the 8% TPS and 12% TPS modified bitumen binders. The shear strain rate and the shear creep modulus of the TPS modified bitumen binders are obtained to compare with those of the SBS modified bitumen binder which results in the same trend as the shear creep strain-time response curve. Permanent deformation results of all the porous asphalt mixtures from the rutting test show reasonable agreement with the findings of the shear strain rates and shear creep modulus over the range of shear stress levels.