冻融循环对泡沫沥青再生混合料微观结构的影响

发布时间：2018-12-09 16:32

【摘要】：为了探究泡沫沥青冷再生混合料抗水损害能力的衰变情况,选取6种不同级配泡沫沥青冷再生混合料,采用劈裂强度试验及电子断层扫描试验,系统研究了不同冻融循环次数下混合料强度衰减特性、空隙级配及最可几孔径的变化规律.结果表明:随着冻融循环的增加,冷再生混合料的强度明显减小,微空隙显著减小,大空隙显著增加,空隙数目的变化直接影响到混合料的强度.电子断层扫描试验及劈裂强度试验结果表明:在总空隙率相同的条件下,微空隙越多混合料强度越高;大空隙越多混合料强度越低.以此为基础提出再生混合料内部空隙的3种分类:无害孔、少害孔及有害孔.前2次冻融循环对冷再生混合料最可几孔径影响最大.在相同的冻融次数下初始空隙率越大泡沫沥青冷再生混合料的最可几孔径越大.
[Abstract]:In order to investigate the decay of water damage resistance of cold recycled foamed asphalt mixture, six kinds of cold recycled asphalt mixture with different grades were selected, and split strength test and electronic tomography test were used. The characteristics of strength attenuation, void gradation and maximum pore size of mixture under different freeze-thaw cycles are systematically studied. The results show that with the increase of freeze-thaw cycle, the strength of cold recycled mixture decreases obviously, the micro-void decreases significantly, and the large void increases significantly. The change of the number of voids directly affects the strength of the mixture. The results of electron tomography and splitting strength tests show that the more microvoids the higher the strength of the mixture and the lower the strength of the mixture with the same total porosity. On this basis, three types of internal voids of recycled mixture are proposed: harmless pore, less harmful pore and harmful pore. The first two freeze-thaw cycles have the greatest influence on the most available pore size of cold recycled mixture. Under the same freeze-thaw times, the larger the initial void ratio is, the larger the maximum pore size of the cold recycled asphalt foamed mixture is.
【作者单位】：云南公投建设集团有限公司;长安大学特殊地区公路工程教育部重点试验室;中交第一公路勘察设计研究院有限公司;
【基金】：国家自然科学基金资助项目(51408050) 云南省科技厅资助项目(2014IA014)
【分类号】：U414

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