沥青混合料级配离析评价指标研究

为弥补沥青混合料配合比设计过程中级配离析评价方法方面的不足，选取SMA-13沥青混合料进行基准配合比以及离析配合比设计，同时采用沥青有效油膜厚度相等的原则设计离析配合比，对级配分形维数指标进行修正，结合分形维数值对SMA-13级配离析进行评价。研究结果表明:基于原分形理论对SMA-13离析级配曲线进行拟合，其拟合结果的相关性差，得到整体的分形维数并不适用于最大粒径小于16 mm的级配。通过有效沥青油膜厚度相等的原则，能够准确计算出不同离析级配对应的油石比，且更加贴近现场的实际情况。采用分段计算级配的分形维数，再按比例计算总的级配的分形维数的方法，解决了由于SMA-13最大粒径过小和自身离析级配的原因而使曲线拟合相关性不高的问题，同时提出了对于SMA-13级配离析的评价标准。

Study on Evaluation Index for Gradation Segregation of Asphalt Mixture

To make up for the deficiencies in the method evaluating gradation segregation in mix proportion design of asphalt mixture, SMA-13 asphalt mixture was selected for the design of basic proportion and segregation proportion, in respect of which the segregation proportion design is in line with the principle of the thickness of effective asphalt film being equal and the fractal dimension index of gradation was corrected, thus, combined with the value of fractal dimension, the gradation segregation of SMA-13 was evaluated. The result shows that, where the segregation-gradation curve of SMA-13 is fitted on the basis of original fractal theory, the fitting result has bad correlation and the overall fractal dimension obtained is not applicable to the gradation with the max. particle size less than 16 mm. Depending on the principle of the thickness of effective asphalt film being equal, the bitumen aggregate ratio corresponding to different segregation grading may calculate accurately, which is closer to the actual situation in the site. The method which calculate the fractal dimension of gradation in segments and then calculate the overall fractal dimension proportionally, was used as the resolution for too small particle size of SMA-13 and bad correlation of curve fitting due to the own segregation gradation, at the same time, the criterion evaluating gradation segregation of SMA-13 was proposed.