高粘度沥青性能评价指标与标准的试验

Viscosity Evaluating Indicators and Criteria of High-viscosity Modified Asphalt

在排水性沥青混合料中,高粘度沥青性能的评价指标和技术要求备受关注.基于沥青材料的常规试验、毛细管粘度试验和动态剪切流变试验,以及排水性沥青混合料的车辙试验和肯塔堡飞散试验,筛选能够体现混合料抗车辙性能和耐久性的沥青性能指标.基于混合料的性能要求,确定高粘度沥青性能指标的技术要求.试验结果表明:沥青材料60℃零剪切粘度、软化点指标与混合料的动稳定度、飞散损失指标之间显著相关,适宜作为高粘度改性沥青性能评价指标;为保证排水性沥青混合料的动稳定度不低于4 000次/mm-1、飞散损失不大于15%的要求,沥青材料60℃零剪切粘度不应低于40 000Pa.s,软化点不应低于85℃.

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.