ATB30在SGC成型中集料破碎分形研究

Study on Fractal Characteristics of Aggregate Crushing of ATB30 in SGC forming

为研究旋转压实的压力参数对大粒径沥青碎石破碎程度影响，选择五种不同竖向压力对三种不同沥青含量的ATB30进行旋转压实试验，对试样进行抽提、筛分，获得粒径分布资料。试验结果表明：集料破碎后的粒径分布均有良好的分形特征，分形维数值在2．4787～2．6260之间；破碎后颗粒增量变化总体特征为，先增加后减小，最后趋于稳定的变化趋势；4．75～9．5mm和16～19mm区间的颗粒有利于抵抗外部荷载，保持骨架密实结构，可以用贝雷法进行验证；破碎分形维数越大，集料破碎量越大，并与Hardin破碎率接近线性关系；集料破碎分形维数随竖向压力增加而呈现先减小后增大规律；沥青含量对分形维数的影响小；采用分形维数可以对沥青混合料的级配进行优化、。

In order to study the effect of pressure parameters of rotating compaction on large size asphalt macadam broken degree, the gyratory compaction test on ATB30 with 3 kinds of asphalt content is carried out under 5 vertical pressures, and the particle size distribution data is obtained after extraction and screening on test specimens. The test result shows that （ 1 ） the particle size distribution of crushed aggregate has good fractal characteristics, the fraetal dimension is between 2. 478 7 and 2. 626 0; （2） the characteristics of crushed particle increment increases at first and then decreases, finally tends to be stable; （3） the particles whose size in the ranges of 4. 75 - 9.5 mm and 16 - 19 mm are good for resisting external loads, keeping dense skeleton structure, which can be verified by Bailey method ; （3） the greater the fractal dimension, the larger the amount of aggregate crushing, and it shows a liner relationship with the Hardin crushing ratio ; （4） with the increase of vertical pressure, the fraetal dimension of aggregate crushing decreases firstly and then increases; （5） asphalt content has little effect on the fractal dimension; （6） dimension can be used to optimize the particle gradation of asphalt mixture.