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

Study on Subtle Structural Performance of Emulsified Asphalt Cold Recycled Mixture under Different Marshall Compaction Methods

基于X-ray CT和数字图像处理技术研究了五种击实方法下乳化沥青冷再生混合料试件内部粗颗粒的颗粒主轴取向角和细微观空隙分布特征,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,同时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。

The particles spindle orientation angle distribution and voids characteristic of emulsified asphalt cold recycled mixture specimen under five compaction methods,were characterized. using Xray CT technology and digital image processing technology Futhermore,propose a mathematical model to characterize the particles spindle orientation angle distribution and voids characteristic by means of statistical analysis. Results showed that： The coarse aggregate orientation angle of emulsified asphalt cold recycled mixture accord Lorentz distribution under Marshall compaction method. The more the second compaction times,the greater the coarse aggregate orientation angle decreases amplitude,While increasing the secondary compaction work to improve the distribution of particles structure of cold recycled asphalt emulsion mix,but far from increasing compaction work the first time the effect is obvious; the percentage of large void significantly reduced of ＂50 ＋ 25 ＂ and ＂60 ＋ 15 ＂ compaction method,With the decrease of the second compaction times,emulsified asphalt cold recycled mixes a mean void size was decreasing trend of first increasing With the decrease of second time compaction times,Marshall specimen has a good linear fit between the average void diameter and splitting strength. Secondary compaction can reduce big void and improve coarse aggregate skeleton structure of cold recycled mixture,considering the influence of compaction method on splitting strength,the presence of coarse and fine particle morphology and the void distribution of cold recycled mixture,recommended use ＂50 ＋ 25＂ method to mold Marshall specimen.