沥青混合料疲劳寿命预测技术研究

Research on Prediction Technology of Fatigue Life of Asphalt Mixture

为研究沥青混凝土的裂缝生成与疲劳寿命,采用级配类型为AC-20的某高速公路的现场钻芯试件,进行室内控制应变疲劳试验;应用劲度变化曲线的裂缝生成机制,与应力-应变回圈面积的消散能理论,推估沥青混凝土疲劳寿命与临界应变。结果表明:应用劲度变化曲线与消散能理论,所得的疲劳寿命都有一致性,故可判断其都可作为疲劳寿命的定义。其中以劲度变化曲线较为便捷,可以作为推估裂缝生成与疲劳寿命的参考方法。

In order to study the cracks generation and fatigue life of asphalt concrete,the strain-controlled fatigue test was done indoors by using drill core specimens on a highway site,the gradation type of specimens was AC- 20.Using cracks generation mechanisms of stiffness changing curve and dissipated energy theory of stress- strain loop area,the fatigue life and critical strain of asphalt concrete were estimated.The results showed the fatigue life using stiffness changing curves agreed with using dissipated energy theory,so the two theories could be used as the definition of judging fatigue life.Among them,stiffness changing curve was convenient,it could be as a reference for estimating cracks generation and fatigue life.