湿度对沥青混合料疲劳性能的影响

Effect of Humidity on Fatigue Performance of Asphalt Mixture

为研究湿度对沥青混合料疲劳性能的影响,对成型的两种沥青混合料试件在温度为20℃条件下,进行2%,50%,80%和100%四个相对湿度水平下的单轴重复直接拉伸疲劳试验.采用修正帕里斯公式分析其疲劳性能,对修正帕里斯公式参数进行拟合求解,分析了湿度对损伤密度增量的影响,提出了基于修正帕里斯公式的疲劳性能评价指标lg A+n对其疲劳性能进行评价.结果表明:湿度对沥青混合料的疲劳性能具有较大的影响,当水气从无到有以及由气态水变为液态水时其影响更为显著.随着湿度的增加,两种沥青混合料的损伤密度增量和评价指标lg A+n的值均呈现上升的趋势.

In order to study the influence of humidity on the fatigue performance of asphalt mixture,uniaxial repeated direct tensile fatigue tests were conducted using two types of asphalt mixture specimens under four humidity levels of 2%,50%,80%and 100%and temperature of 20℃.By fitting and solving the parameters of modified Paris formula,the influence of humidity on damage density increment was analyzed,and the fatigue performance evaluation index lgA+n based on modified Paris formula was proposed to evaluate its fatigue performance.The results show that humidity has a great influence on the fatigue performance of asphalt mixture,and the influence is more significant when the water vapor changes from nothing to liquid water and from gaseous water.With the increase of humidity,the damage density increment and the evaluation index lgA+n of the two asphalt mixtures presented an increasing trend.