Viscosity Evaluating Indicators and Criteria of High-viscosity Modified Asphalt

Abstract:

Evaluating indicators and criteria of high-viscosity modified asphalt are key factors that have significant influence on the performance of open-graded friction course.Tests for asphalt penetration and soften point,vacuum capillary viscometer test,dynamic shear rheological test,wheel tracking test and cantabro loss test are applied to select suitable indicators of asphalt binders for rutting resistance and durability evaluating of open-graded friction course.The test results and analysis show that zero shear viscosity at 60℃ and soften point are significantly related with dynamic stability and scattering loss obtained from wheel tracking test and cantabro loss test,and both indictors are suitable for evaluating the performance of high-viscosity modified asphalt as a result.Besides,dynamic stability no less than 4 000 cycles per millimeter,and scattering loss no more than 15 percent are suggested as the criteria of open-graded friction course.Correspondingly,zero shear viscosity of asphalt binders at 60℃ should be no less than 40 000 Pa·s,and soften point of asphalt binders should be higher than 85℃ to ensure the performance of asphalt mixture.

Key words:road engineering; high-viscosity modified asphalt; indicators and criteria; zero shear viscosity at 60℃; soften point