基于多应力蠕变回复试验的沥青结合料高温性能评价

The High-Temperature Performance Evaluation of Asphalt Binders Based on Multiple Stress Creep Recovery Test

为了更好地评价沥青结合料的高温路用性能,基于动态剪切流变仪(DSR)的应用,选用基质沥青和SBS改性沥青,在通过震荡试验确定沥青PG高温等级的基础上,采用多应力蠕变回复(MSCR)试验对比分析和评价了沥青结合料的高温抗车辙性能.结果表明,现有规范中的震荡试验得到的车辙因子指标G*/sinδ可以很好地评价基质沥青的高温性能(不适用于改性沥青);而MSCR试验得到的回复率R能很好地表征改性沥青的延迟弹性,蠕变柔量J nr则可以考虑取代车辙因子作为沥青结合料高温性能评价的新指标.此外,SBS改性沥青的应力敏感性问题比基质沥青更为显著.

In order to get a better evaluation on high-temperature feature of asphalt binder, conducted on dynamic shear rheometer （DSR） and based on the oscillation test to fix the asphalt PG high-temperature grade, multiple stress creep recovery （MSCR） test was employed to contrastively evaluate the high- temperature rutting potential of neat binder and SBS modified binder. Test results indicate that the G＊ / sin8 determined from the oscillation test in the existing specification is well applied for neat asphalt but really does not work for modified asphalt, whereas the recovery percent R determined from the MSCR test is able to characterize the delay elasticity of modified asphalt well, and the nonrecoverable compliance Jnr measured in MSCR test is developed as a replacement for the G＊/sinδ to evaluate the high-temperature rutting properties for binders. Additionally, the SBS modified binder is found more sensitive to the stress levels than the neat binder.