为深入了解控制模式对沥青疲劳性能的影响,全面掌握沥青的疲劳机理,针对普遍采用的2种基质沥青进行了应力和应变控制模式下疲劳损伤规律的研究。采用动态剪切流变仪,分别对沥青施加应力应变对荷载,对比分析每对荷载作用下沥青的疲劳损伤过程。分析了沥青在应力和应变控制模式下累计耗散能的变化规律;建立了2种控制模式下的累计耗散能增长模型及不同控制模式下累计耗散能的转换关系;提出了不同控制模式下沥青疲劳损伤演化规律的转换方法。研究结果表明:沥青的疲劳过程可以分为黏弹影响阶段和疲劳损伤阶段两部分;当采用应力应变对荷载时,应力、应变控制模式下的累计耗散能-荷载作用次数曲线呈对称关系;累计耗散能增长模型可以很好地拟合沥青疲劳过程中累计耗散能的变化规律;建立的转换方法可以实现应力、应变控制模式下沥青疲劳损伤演化规律的相互转换。
In order to understand the effect of loading control mode on fatigue performance of asphalt binders and know the fatigue mechanism of asphalt binders,the fatigue performance of kinds of two widely used asphalts under controlled-stress and controlled-strain modes were tested and analyzed.The couples of equivalent loading were applied to asphalts by dynamic shear rheometer(DSR),and the fatigue damage processes under the loadings were analyzed.The changing rules of the accumulative dissipated energy under different control modes were analyzed.The growth model and transformation relationship of accumulative dissipated energy under different control modes were established.The method to interconvert the fatigue damage evolution rules under different control modes was proposed.The results show that the fatigue process of asphalt can be divided into viscoelastic effect phase and fatigue damage phase.When choosing the couple of equivalent loadings,the curve of accumulative dissipated energy versus the number of loadingcycles under controlled-stress mode is symmetrical to that under controlled-strain mode.The growth model of accumulative dissipated energy can greatly simulate the changing rule of accumulative dissipated energy in the fatigue process of asphalt.The interconversions of fatigue damage evolution rule under different control modes can be converted by the proposed method.