多轴型加载波交互作用下沥青混合料疲劳损伤演化规律研究

疲劳性能是沥青混合料关键性能之一，该性能受疲劳加载波形的影响。现有混合料疲劳试验多采用正弦加载波形，波形中无间歇或包含固定间歇时间。路面沥青层受多种轴型荷载交互加载，所受加载波形复杂、间歇时间分布不均。现有加载波形无法体现上述特点，难以检测混合料真实疲劳特性。本研究拟采用不同轴型交互作用下路面真实应变波形对沥青混合料进行疲劳试验，探究多种轴型与间歇时间组合下混合料的疲劳损伤演化规律。首先，量化单轴、双轴、三轴等轴型作用下沥青层的加载波形，探究不同轴型加载波对混合料的疲劳损伤作用；其次，参照“单轴-双轴-三轴”等轴型组合，采用不同轴型加载波对混合料组合加载，解析多轴型交替作用下混合料的疲劳损伤叠加机制；最后，在轴型组合中设置轴间间歇及车辆间间歇时间，分析上述间歇时间分布对混合料的损伤愈合效应，明确多轴型与间歇时间交互下混合料的疲劳损伤演化规律，为复杂轴载作用下混合料的疲劳分析提供理论基础。

Fatigue performance is one of the key performances for asphalt mixtures. The fatigue performance of the asphalt mixture is affected by the loading waveform. In the existing fatigue test for asphalt mixture, the sinusoidal wave is generally applied to simulate the loading waveform in asphalt pavement induced by the axle. Between the loading waves, no rest period or a fixed rest period is commonly set. However, the field asphalt mixture layer is subjected to different types of axles, making the strain waveforms in the asphalt layer much more complicated than the sinusoidal wave. In addition, the rest period between the field loading waves is unevenly distributed. The currently used loading waveform is unable to reflect the above characteristics of field loading waveforms, and thus it is insufficient to measure the real fatigue properties of the mixture. This study aims to apply the strain waveform of asphalt pavement layer induced by different axles in the fatigue test, to explore the fatigue damage of asphalt mixture under complex interactions of different axles and rest periods. Firstly, the actual strain waveform of asphalt pavement layer induced by single axle, tandem axles and tridem axles will be determined. The fatigue damage laws of asphalt mixtures under the loading waveforms corresponding to those axles will be analyzed. Secondly, the loading waveforms corresponding to the typical axle configurations such as “single axle-tandem axles-tridem axles” will be used to test the fatigue behaviors of asphalt mixture. The fatigue damage accumulation mechanism of the mixture under the interactive loadings by different axles will be established. Finally, the rest periods will be set between different axles in the typical axle configurations. The fatigue responses of the mixture under the strain waveforms containing rest periods will be utilized to investigate the healing effects of these rest periods on the mixture’s fatigue damage. Based on the above research findings, the fatigue damage evolution law for the mixture under the different axle and rest period combinations will be established, to provide references for the fatigue analysis of the mixture under complex axle loading conditions.