移动轴载作用下路面沥青层动态响应模量主曲线研究

路面沥青混合料层的模量是路面设计的必要参数之一，为定量分析现场沥青层的实际模量特性，提出了一种由现场实测应变数据出发，确定沥青层动态响应模量主曲线的方法，实现了对沥青层现场动态特性的精准表达。首先，实测了柔性基层、半刚性基层2类典型沥青路面不同温度及轴载移动速度下的沥青层动态应变响应；其次，以实测应变波形为基础，分析了不同加载工况下的现场沥青层加载频率特征；最后，基于实测应变值，利用有限元模型反演得到沥青层的动态响应模量，结合沥青层加载频率，建立了沥青层动态响应模量主曲线，并进一步对该主曲线的可靠性进行了验证。研究结果表明：沥青层内部加载频率与轴载移动速度呈正比，且与温度正相关；沥青层现场动态响应模量值随温度升高显著减小，随轴载移动速度增大而增大；结合加载频率及响应模量反演结果，可利用Sigmoidal模型很好地拟合得到沥青层响应模量主曲线；验证结果表明，该主曲线可较为准确地预估其他温度及轴载移动速度下的沥青层响应模量值。所提出的确定沥青层动态响应模量主曲线的方法可为其他试验路应变实测数据的处理提供参考。

Evaluation of Master Curve of Response-based Modulus for Asphalt Pavement Layer Under Vehicular Loading

The modulus of the asphalt pavement layer is an essential parameter for pavement design. To quantitatively analyze the mechanical properties of the field asphalt layer, in this study, a method to determine the modulus master curve of the field asphalt layer based on the measured strain data was proposed. First, the dynamic strain responses of two typical asphalt pavements, specifically, flexible and semi-rigid pavements, under different temperatures and loading speeds, were measured. Secondly, based on the measured strain pulses, the loading frequencies of the asphalt layers were calculated under different conditions. Subsequently, the dynamic modulus of the asphalt layer was back-calculated based on the finite element model and measured strains. Finally, the modulus master curve of the field asphalt layer was established, and the reliability of this master curve was further verified. It is found that the loading frequencies of the asphalt layer increase approximately linearly with the wheel motion speeds. In addition, the frequency values rise with an increase in temperature. The modulus of the field asphalt layer decreases significantly with the temperature but increases with the wheel motion speed. The sigmoidal model was used to fit the master modulus curve of the field asphalt layer combined with the loading frequencies and modulus back-calculation results. This master curve was found to be practicable enough to predict the moduli of the field asphalt layer under other loading conditions. The method proposed in this study can provide a reference for the processing of strain data obtained from other experimental sections.