加载顺序及加载幅值对沥青混合料性能的影响分析

Influence of Load Sequence and Load Amplitude on the Performance of Asphalt Mixture

基于应变控制的沥青混合料四点弯曲疲劳试验,研究了加载顺序和加载幅值对沥青混合料动态黏弹性参数的影响。结果表明:采用先低后高的加载顺序控制时,劲度在两阶段都会随着荷载作用次数的增加而减小,相位角在两阶段会随着荷载作用次数的增加而增加;采用先高后低的加载顺序时,低荷载阶段劲度的变化和相位角的变化会出现两种情况,当高低荷载较为接近时,低荷载阶段的劲度随着荷载作用次数的增加而减小,相位角随着荷载次数的增加而增大;当高低荷载的幅值相差较大时,低荷载阶段的劲度先增大后减小,相位角先减小后增大。通过相位角分别计算出疲劳试验中的黏性模量和弹性模量,揭示了先高后低顺序过程中低荷载阶段劲度先增大后减小和相位角先减小后增大是由于沥青混合料中弹性恢复引起的。

Based on the strain-controlled four-point bending fatigue test of asphalt mixture,the effect of load sequence and load amplitude on the dynamic viscoelastic parameters of asphalt mixture was analyzed.The results show that： under the control of low-high load sequence,the stiffness will decrease but the phase angel will increase in two load levels with the increase of load times; under the control of high-low load sequence,there are two cases of the change of the stiffness and the phase angle in the low load stage.When the low load level is close to the high one,the stiffness will decrease but the phase angle will increase with the increase of load times in the low load stage.When the difference of the amplitude of the high and low load is large,the stiffness in the low load stage will increase first and then decrease,while the phase angle in the low load stage will decrease first and then increase. The viscous modulus and elastic modulus of the fatigue test were calculated respectively by phase angle.In the process of high-low load sequence,the phenomenon that the stiffness in the low load stage increases first and then decreases while the phase angle in the low load stage decreases first and then increases is revealed,which is caused by the elastic recovery in the asphalt mixture.