基于微观力学的沥青混合料黏弹性预测

Viscoelasticity prediction of asphalt mixture based on micromechanics

利用微观力学和逾渗理论预测了沥青混合料的黏弹性能。将沥青混合料看作刚性粗集料颗粒夹杂于黏弹性沥青砂浆基体内的复合材料,在Laplace空间域内利用Mori-Tanaka等效夹杂理论和宏观平均理论,建立了从沥青砂浆黏弹性预报沥青混合料黏弹性的模型。基于逾渗理论修正了模型中的参数,并与静态蠕变试验结果进行了对比。结果发现:粗集料对黏弹性沥青基体性能具有增强作用,沥青混合料黏弹本构方程可以表示为粗集料增强系数与沥青基体黏弹本构方程的乘积形式。微观力学预测的增强系数较试验值偏小,误差分析发现,产生偏差的主要原因是Mori-Tanaka方法考虑集料间相互作用较弱,当粗集料体积分数较大时,预测模型精度下降。通过逾渗理论对粗集料体积分数修正后的结果与试验值较吻合。

The viscoelasticity of the asphalt mixture was predicted by micromechanics and percolation theory. The asphalt mixture was regarded as the composite consisting of the coarse aggregate as the rigid inclusion and the mixture of the fine aggregate, filler and binder as the viscoelastic matrix. A model to predict the viscoelasticity of the asphalt mixture from that of the fine aggregate-filler-binder matrix（AFBM） was deduced in Laplace domain using the Mori-Tanaka equivalent inclusion theory and the macroscopic average theory. The parameters in the prediction model were modified based on the percolation theory, and the predicted results were compared with the ones measured by the static creep test. The results show the coarse aggregate enhances the viscoelastic performance of the fine AFBM. The viscoelastic constitutive relation of the asphalt mixture can be expressed as the product of an enhancement coefficient（EC） and the viscoelastic relation of the fine AFBM. The micromechanics predicted ECs appear smaller than the ones measured by the creep test because the prediction accuracy of the Mori-Tanaka method decreases with the increase of the coarse aggregate volumatric fraction. The ECs modified by the percolation theory agree better with the measured results.