排水性沥青混合料低温性能评价

Evaluation of Low-temperature Performance of Porous Asphalt Mixture

为了分析排水性沥青混合料低温性能的影响因素及评价方法,首先对3种改性沥青的原样、薄膜老化(TFOT)样品、压力老化(PAV)样品进行常规指标试验、-12℃弯曲流变仪(BBR)试验,评价沥青胶结料的低温性能;然后,对几种沥青成型的排水性沥青混合料进行约束试件温度应力试验(TSRST),评价排水性沥青混合料的低温抗裂性能,并通过与长期老化试件TSRST试验结果的对比,分析老化对排水性沥青混合料低温性能的影响。研究结果表明:沥青胶结料BBR试验的劲度模量与排水性沥青混合料的TSRST试验结果有很好的一致性;老化后的排水性沥青混合料冻断温度升高、冻断应力减小,低温性能降低;排水性沥青混合料的冻断应力约为密级配沥青混合料的1/3,冻断温度相近,2种类型沥青混合料低温性能相差不明显。

To analyze influencing factors and evaluation method of low-temperature performance of porous asphalt mixture, first, three kinds of modified binder were chosen as original, thin film aging and pressure aging samples for customary index test and bending beam rheometer （BBR） test at - 12 ℃ to evaluate low-temperature performance of these modified binders. Then, evaluation of the low-temperature anti-cracking performance of different kinds of porous asphalt mixture was made by thermal stress restrained sample test （TSRST） . At the same time, the result of abovementioned TSRST were compared with the TSRST result of samples of the porous asphalt mixtures after long-term aging to evaluate the influence of aging on low-temperature performance of porous asphalt mixtures. The result shows that （ 1 ） TSRST result of porous asphalt mixtures coincides with creep stiffnesses of BBR test of modified binders; （2） the fracture temperatures of the porous asphalt mixtures increase and their fracture stresses decrease after aging; （3） the fracture stresses of porous asphalt mixtures are just one-third of those of dense-gradation asphalt mixtures while the fracture temperatures almost the same, which indicates that their low- temperature performances are almost the same.