基于介电性质的沥青抗老化性能量化表征与分析

Quantitative Characterization and Analysis of Asphalt Aging Resistance Based on Dielectric Properties

关键词:  沥青  老化  量化表征  流变性能  介电常数

Key words:  asphalt  aging  quantitative characterization  rheological property  dielectric constant

摘要:

通过对热氧老化前后的90^#基质沥青、苯乙烯-丁二烯-苯乙烯嵌段共聚物（SBS）改性沥青进行三大指标、布氏黏度、频率扫描、线性振幅扫描和介电常数测试，研究了老化前后沥青基础指标、流变学指标、疲劳性能及沥青组分的变化情况，量化了短、长期老化后各指标的变化情况，并建立了沥青组分与性能指标之间的量化关系.结果表明：采用三大指标描述沥青老化程度时，针入度指标评价最为合理；基质沥青的黏度、温度敏感性、复数剪切模量主曲线和抗疲劳性能受热氧老化的影响大于SBS改性沥青；基质沥青的黏度和温度敏感性在短期老化过程中变化更明显，SBS改性沥青的黏度和温度敏感性在长期老化过程中变化更明显；2种沥青的抗疲劳性能和复数剪切模量的衰减主要发生在长期老化过程中；采用介电常数对沥青组分进行划分，并以此关联沥青老化前后性能变化的分析方法是可行的.

Abstract:

Through the tests of three indexes， Brookfield viscosity， frequency scanning， linear amplitude scanning and dielectric constant of 90 ^# base asphalt and styrene-butadiene-styrene block copolymer （SBS） modified asphalt before and after thermal-oxidative aging， the changes of asphalt basic indexes， rheological indexes， fatigue properties and asphalt components before and after aging were studied. Moreover， the changes of indexes after short-term and long-term aging were quantified and the quantitative relationship between components and performance indexes was established. The results show that penetration is the most reasonable one among three indexes to describe asphalt aging degree. The viscosity， temperature sensitivity， complex modulus modulus master curve and fatigue resistance of base asphalt are much affected by thermal-oxidative aging than that of SBS modified asphalt. The viscosity and its temperature sensitivity of base asphalt change much obviously during short-term aging， while SBS modified asphalt change much obviously during long-term aging. The attenuation of fatigue resistance and complex shear modulus of the two asphalts mainly occurs in the long-term aging. It is feasible to use the permittivity to divide the asphalt components and correlate the performance changes of asphalt before and after aging.