Research On Test Methods And Calculation Models For Asphalt Zero Shear Viscosity

With the development of transportation industry in China, the requirements for evaluating a high-temperature performance of modified asphalt has become higher and higher. The current Superpave Asphalt binding material specification by dynamic shear test to calculate the rutting factor G*/sin?, in order to evaluate asphalt high-temperature performance. However, FHWA and asphalt association test proved that the rutting factor G*/sm?does not evaluate high-temperature performance well, many sections of the test results confirm high-temperature PG grades for the same asphalt road performance differences, which prompted the road workers to focus on seeking better high-temperature performance evaluation. index. So led by many countries and regions focused on the zero shear viscosity of asphalt (Zero Shear-rate Viscosity, ZSV).In this paper, firstly illustrated the concept of shear viscosity and zero shear viscosity of asphalt. Then, introduced several test methods and calculation models to obtain zero shear viscosity. Finally, using creep-recovery test results of high viscosity rubber modified asphalt, obtained zero shear viscosity with recovery compliance of Burgers model. Based on the creep recovery data of three kinds of stress, recovery compliance and time curves were fitted, and the recovery period was getting longer to 17.5-18s and compared the zero shear viscosity at 10s and 20s. The results show that stress level of applied stress level is very low when the zero shear viscosity is measured. If the stress level is high, recovery period has to be long to attain a constant recovery compliance.