高层位乳化沥青冷再生混合料水稳定性研究

Study on Water Stability of High-level Emulsified Asphalt Cold Recycled Mixtures

为了更加真实准确地评价高层位乳化沥青冷再生混合料通车后的抗水损害性能,文中在实体工程路面现场钻取芯样并开展了水稳定性试验。首先在冷再生层成型后1~8 d分别钻取路面芯样,分析了养生时间对劈裂强度的影响;其次以新铺SMA罩面层作为对比,分析了不同类型路面芯样的干湿劈裂强度比和冻融劈裂强度比。结果表明,养生时间对乳化沥青冷再生混合料劈裂强度的影响显著,分别在养生3 d和7 d达到早期强度的两个稳定期。乳化沥青冷再生层的干湿劈裂强度比和冻融劈裂强度比明显小于新铺SMA罩面层,且存在不达标的情况,水稳定性提升是乳化沥青冷再生混合料用于高层位再生时需重点关注的问题。

In order to evaluate the anti-raveling performance of emulsified asphalt cold in-place recycling mixture in high layer recycling pavement more accurately,coring samples were drilled in practical engineering after opening to traffic,and moisture susceptibility tests were carried out.Firstly,the pavement coring samples were drilled from 1 to 8 days after the cold in-place recycling layer was compacted,and the effect of curing time on splitting strength was analyzed.Then,compared with the new paved SMA overlay,the dry-wet splitting strength ratio and freeze-thaw splitting strength ratio of different types of coring samples were measured.The test results show that the effect of curing time on splitting strength of emulsified asphalt cold recycling mixture is significant,and the two stable periods of early strength are reached after curing 3 days and 7 days respectively.The dry-wet splitting strength ratio and freezing-thawing splitting strength ratio of emulsified asphalt cold recycling layer are obviously lower than that of SMA overlay,and the situation not up to the standard is existed.The improvement of moisture susceptibility is a key issue when emulsified asphalt cold recycling mixture is used for high recycling layer.