基于原子力显微镜技术的温拌沥青老化过程中粘附特性研究

发布时间：2018-01-31 09:52

本文关键词： 道路工程温拌沥青老化粘附特性 AFM 表面能表面形貌　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,可以适当的降低混合料拌合、路面碾压的温度,不仅减少了污染气体和粉尘的排放、降低了资源消耗,也在一定程度上避免了沥青的前期老化。但其降低拌合、施工温度的技术特点使其后期使用性能受到了很大的挑战,特别是温拌沥青路面在服役过程中表现出的抗水损害能力不足使温拌沥青混合料的应用受到了很大的限制。沥青混合料发生水损害的主要原因是,沥青在长期的服役过程中发生老化,加之水的存在导致沥青与集料间的粘附力下降,最终导致沥青路面的破坏,因此研究温拌沥青老化过程粘附特性对温拌沥青混合料的推广使用有重要意义。本文选用甘肃地区常用的三种90#道路用重交基质沥青(SK、埃索以及克炼)、两种不同作用机理的温拌剂(Sasobit和Evotherm)配制温拌沥青,并通过原子力显微镜(AFM)、凝胶渗透色谱(GPC)、红外光谱(FTIR)等微观手段,结合表面能等宏观方法研究了温拌沥青在短期老化(RTFO)、长期老化(PAV)过程中表现出的不同粘附特性。首先,通过AFM形貌观察分析了沥青表面的微观形貌,研究了添加温拌剂和老化过程对沥青微观形貌的影响;其次,利用AFM力谱试验测试纳观粘附力,结合宏观表面能试验分析不同老化过程对温拌沥青粘附特性的影响;最后,采用GPC试验分析温拌沥青老化过程中各分子含量的变化、采用FTIR试验分析温拌沥青老化过程中各官能团的变化,结合GPC和FTIR研究温拌沥青老化机理。研究结果表明:首先,添加温拌剂和不同程度的老化对沥青形貌图都有一定程度的影响,Sasobit温拌剂增加了“蜂状结构”的高度,Evotherm温拌剂则降低了“蜂状结构”的高度。短期老化和长期老化都使“蜂状结构”的高度增加,并显著的提高了沥青表面的粗糙度,老化后沥青相图中各相的界限变得模糊不清,值得注意的是克炼沥青在老化后形貌图变化较大,出现了基质沥青中没有的“蜂状结构”;其次,AFM纳观粘附力测试结果和表面能结果一致并有较高的拟合度,即添加Evotherm温拌剂提高了基质沥青的粘附力,而Sasobit降低了基质沥青的粘附力,随着老化过程的加剧,温拌沥青粘附力逐渐降低;最后,红外光谱试验结果表明,克炼沥青的C=O键振荡峰明显强于SK和埃索沥青。加入Sasobit后基质沥青中代表亚砜峰的S=O键数量减少,加入Evotherm温拌剂后,三种沥青的S=O键含量均有所增加,短期老化后各沥青的S=O键吸收峰有显著的加强。长期老化后,C=O键吸收峰和S=O键吸收峰大幅增加。此外,基质沥青中加入Evotherm温拌剂后,大分子含量有所下降,小分子含量有所上升,加入Sasobit温拌剂后,大分子含量有所上升,小分子含量有所下降。经过短期和长期老化后,三种基质沥青的大分子含量都有所增加而中分子和小分子都有所减少。
[Abstract]:Warm mix asphalt mixture (WMA) is a kind of green road building material which can save energy and reduce emission. It can reduce the temperature of mixture mixing and road surface compaction and not only reduce the emission of pollution gas and dust. It reduces the consumption of resources and avoids the pre-aging of asphalt to a certain extent, but the technical characteristics of its mixing and construction temperature make its performance in the later period greatly challenged. Especially the lack of water damage resistance of warm asphalt pavement makes the application of warm mix asphalt mixture greatly limited. The main reason of water damage of asphalt mixture is. Asphalt aging in the long service process, coupled with the existence of water to reduce the adhesion between asphalt and aggregate, and ultimately lead to the destruction of asphalt pavement. Therefore, it is very important to study the adhesion characteristics of warm mix asphalt during aging. In this paper, three kinds of heavy base asphalt SK used in 90# road in Gansu area are selected. Esso and ketamine, two different mechanisms of warm mixing agents, Sasobit and Evothermum, were used to prepare warm mix asphalt, and AFM was used by atomic force microscope (AFM). Microcosmic methods such as gel permeation chromatography (GPC), infrared spectroscopy (FTIR) and macroscopical methods such as surface energy were used to study the short term aging of warm mixed asphalt (RTFOF). Different adhesion characteristics were observed in the process of long-term aging. Firstly, the surface morphology of asphalt was observed and analyzed by AFM. The effects of warm mixing agent and aging process on the microstructure of asphalt were studied. Secondly, the AFM force spectrum test was used to test the adhesion force, and the influence of different aging processes on the adhesion characteristics of warm mixed asphalt was analyzed by combining with the macroscopic surface energy test. Finally, GPC test was used to analyze the changes of molecular content in the aging process of warm mixed asphalt, and FTIR test was used to analyze the changes of functional groups in the aging process of warm mixed asphalt. Combined with GPC and FTIR to study the aging mechanism of warm mix asphalt. The results show that: first, the addition of warm mix agent and different degrees of aging have a certain degree of impact on the asphalt morphology. The Sasobit warm mix increased the height of the "wasp structure". The height of "bee structure" was decreased by Evotherm warm mix agent, and the height of "bee structure" was increased by both short-term aging and long-term aging, and the roughness of asphalt surface was improved significantly. After aging, the boundaries of each phase in the phase diagram of asphalt become blurred. It is worth noting that the morphology of asphalt after aging changes greatly, and there is a "bee structure" which is not found in the matrix asphalt. Secondly, the results of AFM nano-adhesion test are consistent with the surface energy results and have a higher fit, that is, the addition of Evotherm warm mix agent can improve the adhesion of the matrix asphalt. Sasobit decreased the adhesion of the asphalt, and the adhesion of the warm mixed asphalt decreased with the aggravation of the aging process. Finally, the results of IR spectra showed that the oscillatory peaks of C _ (O) bond in the pitch were obviously stronger than those in SK and Esso asphalt, and the number of Sino O bonds representing sulfoxide peak in the base asphalt was decreased after adding Sasobit. After adding Evotherm warm mix agent, the content of Sn-O bond of the three kinds of asphalt increased, and the absorption peak of Sn-O bond of each asphalt increased obviously after short-term aging, and the absorption peak of Sn-O bond was significantly strengthened after long-term aging. The absorption peaks of C-O bond and Sn-O bond increased significantly. In addition, the content of macromolecule decreased and the content of small molecule increased with the addition of Evotherm in the base asphalt. The content of macromolecule increased and the content of small molecule decreased after the addition of Sasobit warm mix agent, and after short-term and long-term aging, the content of macromolecule increased and the content of small molecule decreased. The macromolecular content of the three kinds of bitumen increased, while the medium and small molecules decreased.
【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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