基于虚拟抗压试验的沥青混合料质量均匀性评价方法研究

A research on evaluating quality homogeneity of asphalt mixtures with virtual compression tests

沥青路面质量均匀性评价指标过于单一、宏观,缺乏细观结构力学特性的评价方法。选取了6个沥青路面芯样,首先利用AVIZO软件改进了对CT图像组分识别与处理技术,使颗粒与颗粒间能较好地分离。其次编写了MATLAB程序将各组分空间分布信息导入ABAQUS平台中,实现了沥青混合料数值芯样重构。最终,对低温弹性体的有限元抗压力学模型进行抗压力学分析,并利用截面抗压应力均值和应力分量不均匀系数作为评价指标。结果表明:(1)S33(在Z轴方向的应力分量)应力场可直观地认识应力分布与接触面积的关系,在空隙分布较为均匀的截面中,S33的应力均值偏小;(2)利用截面抗压应力均值和应力分量分布不均匀系数指标,可有效描述沥青混合料芯样的质量不均匀性。

Six core specimens of asphalt pavement were studied. Technologies for identifying and processing CT digital images were improved by using AVIZO software. These technologies and X-ray computed tomography were employed to clearly desc ribe the microstructures(e.g. spaces and aggregates distributions) in these core specimens. Numerical models of asphalt mixture were set up in ABAQUS software with a help of a written program in MATLAB. Finite element analyses were carried out with assumed low temperature elastic body under compressive loads. Results show that(1) a relationship between stress distributions and contact areas are directly realized by the S33(stress component in Z axial direction) stress field, and there is a small stress average in the section with homogenous distribution of air void;(2) averages of the compressive stresses and the non-uniformity coefficients are suitable indicators for evaluating homogeneity of asphalt mixtures.