利用韧性比指标进行改性沥青低温性能评价

为了评价改性沥青低温性能,采用FDT试验进行研究,并将试验结果与沥青常规试验及SHRP试验结果进行比较,验证了FDT试验的可行性。基于FDT试验提出了新的沥青低温性能评价指标韧性比RT/V,然后利用RT/V进行多种不同改性沥青的低温性能评价,并比较常规试验指标及SHRP试验指标。结果表明,利用韧性比指标进行沥青低温性能评价与用常规指标和SHRP指标具有高度一致性,而且FDT试验具有操作简单,设备价格低廉等优点,因此利用韧性比进行沥青低温性能评价具有可行性。同时通过RT/V与BBR试验的m值相关性分析,提出要使得改性沥青具有良好的低温抗裂性能,即BBR试验的m值大于0.3,则要求RT/V不小于5.4。

Evaluation of Low-temperature Performance of Modified Bitumen Using RT/V Index

In order to evaluate low-temperature performance of modified bitumen,FDT test was conducted.At the same time the results of FDT test,general test and HHRP test are compared to validate the feasibility of FDT test.The new index RT/V for evaluating anti-cracking performance of modified bitumen at low temperature is proposed based on FDT test,RT/V is defined as the ratio of tenacity to viscous-elastic,which is calculated through FDT curves.Low-temperature performance of different modified bitumen are evaluated using RT/V.Comparing the evaluation results using RT/V with that using general index and SHRP index,it has been found that all the evaluation results using variable indexes are almost accordant and due to simplicity of FDT test and cheapness of device RT/V could be used to evaluate modified bitumen low-temperature performance.At last through relativity analysis of RT/V and m obtained from BBR test,it is concluded that modified bitumen would have better anti-cracking performance at low temperature as m greater than 0.3 if RT/V exceed 5.4.