考虑老化的温拌沥青混合料低温性能

Low-temperature anti-cracking property of warm asphalt mixture with different aging degrees

  • 摘要: 为明确温拌沥青混合料中温拌剂和热老化对混合料低温性能的影响,对原样、短期老化、长期老化的沥青混合料,利用UTM-100进行了0℃、-10℃和-20℃下的小梁弯曲试验和小梁弯曲蠕变试验。研究结果表明:可用蠕变试验数据拟合出伯格斯模型参数,计算出温度应变能密度,进而由弯曲和蠕变试验结果预估出温拌沥青混合料的开裂温度,作为评价温拌沥青混合料低温性能的一个综合指标;可以用延时拌和法表征沥青混合料在短期老化过程中达到平均老化程度的热老化方法;沥青混合料在不同温度、不同老化程度下低温性能发生变化是由于拟合参数发生了变化;温拌剂在一定程度下增加了沥青混合料的抗短期老化性能;发现加入有机降黏型RH温拌剂会降低沥青混合料的低温性能,而益路温拌剂对沥青混合料的低温性能有利,故在寒冷地区推荐使用益路温拌剂。

     

    Abstract: In order to clarify the effect of low-temperature performance of warm-mixed asphalt mixture from warm-mixed agent and heating aging, the trabecular creep experiments, which are about original asphalt mixture, short-term aging and long-term aging asphalt mixture, were conducted by UTM-100 at temperature of 0℃, -10℃ and -20℃. The results show that the Burgess model parameter can be fitted by using the creep test data, then the temperature and strain energy density can be calculated, and the cracking temperature of the warm-mixed asphalt mixture can be predicted based on the creep test results, which can be used as a comprehensive index for the low-temperature performance of the asphalt mixture. The delayed mixing method can be taken as a method of characterizing the average aging degree of asphalt mixture in short-term aging process. The low-temperature performance of asphalt mixture at different temperatures and different aging degrees changes because of the fitting parameters. Warm-mixed agent can increase the short-term aging performance of asphalt mixture to a certain extent. It is found that the low-temperature performance of asphalt mixture can be reduced by adding RH warm-mixed agent, while Evotherm warm-mixed agent is beneficial to the low-temperature performance of asphalt mixture, so the Evotherm warm-mixed agent is recommended to be used in the cold area.

     

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