不同马歇尔击实方法乳化沥青冷再生混合料细微观结构性能研究

采用工业CT无损检测技术(X-ray CT)和数字图像处理技术研究“30+45”、“40+35”、“50+25”、“60+15”、“75+0”五种马歇尔击实方法下乳化沥青冷再生混合料试件的内部的粗颗粒的颗粒主轴取向角和空隙特征分布特征,并通过统计分析提出数学模型对其进行表征。结果表明：马歇尔击实方式下乳化沥青冷再生混合料粗集料取向角基本符合洛伦兹分布,第二遍击实次数越多,粗集料取向角减小幅度越大,增大二次击实功虽然可改善乳化沥青冷再生混合料的颗粒分布结构,但远没有增大第一次击实功效果明显;“50+25”、“60+15法”空级配中大孔百分比明显减小,而小孔百分比显著增大,随着第二遍击实次数的减小,乳化沥青冷再生混合料平均孔径呈先减小后增大的变化趋势,马歇尔试件平均孔径与劈裂强度之间具有良好的线性拟合关系。二次击实可减小乳化沥青冷再生混合料内部的大孔,改善粗集料的骨架承载结构,综合考虑击实方法对乳化沥青冷再生混合料劈裂强度、粗颗粒存在形态以及细微观空隙分布特征的影响,推荐采用“50+25法”成型马歇尔试件。

Study on Microstructure of Emulsified Asphalt Cold Recycled Mixture with Different Marshall Compaction Methods

based on industrial CT non-destructive testing (X-ray CT) and digital image processing "30+45","40+35 0" five Marshall compaction methods were studied and the distribution characteristics of the principal axis orientation and void characteristics of the coarse particles in the emulsified asphalt cold reclaimed mixture under the Marshall compaction method were studied. The mathematical model was used to characterize the parameters. The results show that the orientation angle of the coarse aggregate in the emulsified asphalt cold mix is in accordance with the Lorentz distribution in the Marshall crushed mode. The more the number of times of the second pass is, the larger the roughness is, However, it is possible to improve the particle distribution structure of the emulsified asphalt cold reclaimed mixture, but it is far from increasing the effect of the first strike. The "50+25" and "60+15" The average pore size of the emulsified asphalt cold reclaimed mixture was decreased first and then increased, and the average pore size and splitting of the Marshall specimen were significantly decreased with the decrease of the second pass. The crack strength has a good linear fitting relationship. The secondary compacting can reduce the large pores in the emulsified asphalt cold reclaimed mixture and improve the skeleton bearing structure of the coarse aggregate. Considering the compaction method, the splitting strength, the coarse particle morphology and the microscopic view of the emulsified asphalt cold reclaimed mixture Void distribution characteristics of the impact of the proposed "50 +25 method" forming Marshall specimens.