考虑应变和加载频率的RAP沥青混合料疲劳特性分析

Effects of RAP on the Fatigue Life of Asphalt under Different Strain Levels and Loading Frequencies

系统研究了RAP、加载频率和应变水平对沥青混合料及结合料的疲劳特性的影响,并确定了沥青混合料和结合料疲劳寿命之间的关系。通过梁疲劳试验对两种沥青混合料的疲劳特性进行了对比分析,一种含有RAP,一种不含RAP;分别从这两种混合料中提取了沥青结合料,并进行重复加载疲劳试验。结果表明:RAP会降低沥青混合料的疲劳寿命,延长沥青结合料的疲劳寿命;加载频率越高,沥青混合料和沥青结合料的疲劳寿命越长;应变水平越高,沥青混合料和结合料的疲劳寿命越短。

This study examines the effects of RAP, loading frequency and strain level on the fatigue properties of asphalt mixtures and binders. In addition, the relationship between the fatigue lives of asphalt mixture and binder is determined. Beam fatigue tests were conducted to compare and analyze the fatigue properties of two asphalt mixtures： one with RAP and the other without RAP. To evaluate binder＇ s fatigue behavior, binders were extracted and recovered from these two mixtures respectively , on which TS tests were conducted. Results show that presence of RAP in mixture causes a decrease in the mixture＇ s fatigue life, and an increase in the fatigue life of binder. An increase in loading frequency results in an increase in the fatigue lives of asphalt mixture as well as binder; increase in strain level causes a decrease in the fatigue lives of both mixtures and binders.