沥青砂动态剪切蠕变特性

为了解沥青砂的复杂力学行为,给沥青混合料细观力学研究提供数据支持,将几种沥青混合料的配合比转变为沥青砂的配比,采用自主研发的沥青砂成型装置及流变仪夹具获取沥青砂的动态剪切蠕变曲线,基于Burgers模型对蠕变曲线进行拟合,获取动态剪切荷载下沥青砂的黏弹性参数,分析黏弹性参数及松弛模量的变化规律。试验结果显示,Burgers模型对沥青砂动态剪切蠕变曲线具有较好的拟合效果。相同加载时间内,相比于AC-20级配沥青混合料,SMA-16级配沥青混合料蠕变变形量更大。橡胶沥青砂的抗剪切蠕变性能最优。沥青砂蠕变变形影响规律与混合料车辙变形一般影响规律相符。试验温度、沥青用量、沥青种类和级配类型均对沥青砂的黏弹性参数和松弛模量影响显著。

Dynamic shear creep characteristics of asphalt mortar

To consider the complex mechanical behavior of asphalt mortar and provide the data surpport for asphalt mixture micromechanics analysis, several asphalt mixture mixing ratios were transferred into asphalt mortar mixing ratios. Asphalt mortar molding device and discovery hybrid rheometer fixtures developed by ourselves were used to obtain the dynamic shear creep curves. Burgers model was used to fit the creep curves. The viscoelastic parameters of asphalt mortar under dynamic shear loading condition were obtained. The changing rules of the viscoelastic parameters and the relaxation modulus were analyzed. Results showed that Burgers model had good fitting effect on dynamic shear creep curve of asphalt mortar. The creep deformation of SMA-16 corresponding asphalt mortar was larger than AC-20 within the same loading time. Rubber asphalt mortar had the optimal shear creep resistant properties. The asphalt mortar creep deformation had the same influence rules with the general influence rules of asphalt miture rutting deformation. Test temperature, asphalt contant, type of asphalt and aggregate gradation all had obviously influence on asphalt mortar dynamic shear creep viscoelastic parameters and relaxation modulus.