On the Effect of Testing Conditions on the Apparent Viscosity of SBS Modified Asphalt

Viscosity is an important property of asphalt,and has a close relationship with the construction temperature and workability of the asphalt mixtures. In order to evaluate the effect of testing conditions on the viscosity,the apparent viscosity of SBS modified asphalt under different times,different temperatures,and different shear rates is studied by using Brookfield viscometer. The results shows that the apparent viscosity of SBS modified asphalt is tending towards stability with time increasing gradually. The higher the temperature and the greater the shear rate,the shorter the time for viscosity stabilizing and the smaller the difference between the initial viscosity and stable viscosity. When the testing temperature exceeds 150 ℃,the variation of shear rate has little effect on the viscosity. The shear rate should be no less than 20 RPM when the viscosity of SBS modified asphalt is measured at different temperatures.