基于细观力学的沥青混合料动态模量预测

为了建立能够表征组分材料性能及细观结构特征的沥青混合料动态模量预测模型, 根据复合材料细观力学理论, 将沥青混合料视为由沥青胶浆包裹的集料颗粒嵌入于有效沥青混合料介质中的复合材料, 考虑集料尺寸、级配组成和空隙的影响, 建立了沥青混合料动态模量三相细观力学预测模型。结合组分材料性能研究, 应用该预测模型求解得到了动态模量, 其与试验值比较结果表明, 预测值较试验值小, 产生此差异的原因可归结为模型的适用条件与真实细观结构的差别;据此对预测模型进行了修正, 提出了考虑沥青膜厚度的动态模量细观力学分析方法;鉴于集料与沥青胶浆之间的力学特性差异, 简化了预测模型求解参数, 给出了参数值的范围。

DYNAMIC MODULUS PREDICTION OF ASPHALT MIXTURES BASED ON MICROMECHANICS

To establish a dynamic modulus prediction-model of asphalt mixtures indicating properties of inclusions and characteristics of microstructure, a three phases micromechanics model to predict dynamic modulus of asphalt mixtures is developed, based on the micromechanics theory of composite. Asphalt mixtures is regarded as a composite by embedding the mastic (asphalt binder) coated aggregate particles into the equivalent medium of asphalt mixtures, and the effect of aggregate size, aggregate gradation and air void distribution are taken into account in this model. The dynamic modulus of asphalt mixtures is then predicted with the newly developed micromechanics model using the studies on properties of inclusions. Laboratory test results show that the predicted dynamic modulus is smaller than measured dynamic modulus. The reasons for the discrepancy between the measured and predicted results might be attributed to the distinction between the assumption of the prediction model and rigorous micromechanical structure. The prediction model is modified by the given analysis, and then a micromechanics methods considering asphalt film thickness is proposed. Whereas the difference of mechanical properties between aggregate and mastic, the solution parameters of the prediction model is simplified, furthermore the range of the parameters value is presented.