温拌沥青混合料老化过程中水稳定性的多尺度研究

发布时间：2018-01-12 13:31

本文关键词：温拌沥青混合料老化过程中水稳定性的多尺度研究　出处：《兰州交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：温拌沥青混合料(WMA)是一种节能减排的绿色筑路材料,其降低沥青混合料搅拌与压实温度的技术特点使其水稳定性问题较热拌沥青混合料(HMA)更复杂。其水稳定性更是目前业界担忧的问题,在某种程度上限制了WMA技术的进一步发展。如何提高温拌沥青混合料水稳定性已成为工程技术部门必须考虑和亟待解决的问题。而在WMA应用过程中发现WMA混合料在老化过程中水稳定性有一定改善。因此本研究主要针对老化过程中的温拌沥青混合料的水稳定性宏观(浸水马歇尔、冻融劈裂)表征、温拌沥青流变特性(DSR)、温拌沥青物化性能(表面能、红外光谱)进行了多尺度的试验研究。同时综合运用多种统计学分析方法,对物化性能与宏观表征的关联展开统深入地研究,主要研究内容及成果如下:采用冻融劈裂、浸水马歇尔试验对于SK基质沥青+温拌剂(Sasobit、Evotherm)的短期老化(老化时间2h/4h/8h,老化温度112℃/129℃/146℃)及长期老化((老化温度60℃,老化时间7d/14d/28d/56d))过程中WMA混合料水稳定性进行了测试。研究结果表明:WMA混合料的水稳定性随着短期老化的进行而增加,在某一老化阶段其水稳定性将优于热拌沥青混合料。Evotherm-WMA混合料的水稳定性在短期老化程度较低时其水稳定性优于Sasobit-WMA混合料,但是随着老化程度的不断增加,Evotherm-WMA混合料的水稳定性增幅程度小于Sasobit-WMA混合料,在某一短期老化程度时将小于Sasobit-WMA混合料。随着短期老化的加剧,Evotherm+WMA混合料的水稳定性将趋于Sasobit+WMA混合料。随着长期老化时间在一定范围内的增加,WMA混合料的水稳定性先增加后减小。同时在浸水马歇尔试验中发现Evotherm+WMA混合料的残留强度比将会出现超百现象。采用DSR试验进行了抽提沥青的流变特性研究。研究结果表明随着老化程度的增加,温拌沥青老化指数缓慢增加,其表明在短期老化过程中会发生沥青的老化,但在一定范围老化内温拌沥青老化速率较低。采用表面能、红外光谱进行温拌沥青老化过程中粘附/微观研究,结果发现随着短期老化的进行温拌沥青表面能有所增加,Evotherm+SK的表面能高于Sasobit+WMA,WMA混合料的水稳定性与表面能有显著相关性,即温拌沥青的表面能越大WMA混合料水稳定性越好。随着短期老化的进行温拌沥青S=O键在两种温拌沥青中表现规律并不一致。而C=O键随着老化的进行而增加,但其增加程度弱小几乎为零,表明温拌沥青老化程度很小。而随着短期老化的进行C=C键却在某种程度上随之增加。同时C=C键与WMA混合料冻融劈裂强度比显著相关,温拌沥青C=C键含量的改变可能是WMA混合料老化过程中水稳定性变化的根本原因。本研究旨在揭示不同老化条件下温拌沥青混合料水稳定性变化规律及其对应的温拌沥青流变特性、沥青表面能及微观结构变化,探讨WMA混合料老化过程中水稳定性变化原因。为客观评价WMA的水稳定性提供理论与实验依据,对有效控制WMA水损害具有重要的理论意义与参考价值。
[Abstract]:Warm mix asphalt (WMA) is a kind of green energy saving materials, reducing the asphalt mixing characteristics and compaction temperature to the water stability than hot mix asphalt (HMA) is more complicated. The water stability is the industry's concerns, to some extent limit the further development of WMA technology. How to improve the water stability of warm mix asphalt mixture has become urgent problems must be considered and the engineering department. And found in the WMA application process of WMA mixture was improved in the aging process of water stability. The research is mainly in the warm mix asphalt mixture in the aging process of water the stability of macro (Marshall immersion, freeze-thaw splitting) characterization, the rheological properties of warm mix asphalt (DSR), the performance of warm mix asphalt material (surface energy, infrared spectroscopy) were studied. At the same time using multi scale A variety of statistical analysis method, correlation of physicochemical properties and characterization of macro expansion system in-depth study, the main research contents and results are as follows: the freeze-thaw splitting, immersion Marshall test for SK asphalt + warm mix agent (Sasobit, Evotherm) of short-term aging (aged between 2h/4h/8h, the aging temperature of 112 DEG /129 DEG /146 (c) and long-term aging (aged 60 degrees Celsius temperature, aging time 7d/14d/28d/56d)) in the process of WMA mixture water stability were tested. The results show that the water stability of WMA mixture increases with the short-term aging, in an aging stage the water stability of the water stability is better than hot mix asphalt mixture.Evotherm-WMA mixture in the short-term aging degree is very low when the water stability is better than that of Sasobit-WMA mixture, but with the increase of aging degree, water stability increased Evotherm-WMA mixture is less than S Asobit-WMA mixture, in a short-term aging degree will be less than Sasobit-WMA. The mixture with short-term aging intensifies, water stability of Evotherm+WMA mixture and Sasobit+WMA mixture will tend to increase with the long aging time within a certain range of WMA mixture water stability first increased and then decreased. At the same time in the immersion Marshall test Evotherm+WMA mixture of residual strength over 100 than will the DSR test. Study on the rheological properties of asphalt were extracted. The results show that with the increase of aging degree, aging temperature asphalt index increased slowly, suggesting that aging occurs in a short pitch in the aging process, but in a certain range of temperature and aging asphalt aging rate is low. The surface energy, infrared spectrum of warm mix asphalt adhesion aging process / microscopic study, found that the short-term aging. For warm mix asphalt surface can increase the surface energy of Evotherm+SK is higher than Sasobit+WMA, and the surface water stability of WMA mixture can have significant correlation, namely the surface of warm mix asphalt can better water stability is WMA mixture. With the short-term aging of warm mix asphalt S=O key rules in two kinds of warm mix asphalt in not the same. While the C=O bond with aging were increased, but the increasing extent of the weak is almost zero, that warm mix asphalt aging degree is very small. With the short-term aging of C=C bond has increased to some extent. At the same time, C=C key and WMA mixture freeze-thaw splitting strength ratio was significantly correlated. Warm mix asphalt C=C bond content change may be the underlying cause of ageing process water stability change of WMA mixture. The purpose of this study is to reveal the mixture water stability variation of warm mix asphalt and its corresponding temperature under different aging conditions The rheological properties of asphalt, the change of surface energy and microstructure of asphalt mixture were discussed, and the reasons for the change of water stability during the aging process of WMA mixture were discussed. It provides theoretical and experimental basis for objectively evaluating the water stability of WMA, and has important theoretical significance and reference value for effective control of WMA water damage.

【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

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