导电沥青混凝土的导电特性与工程应用研究

发布时间：2018-07-05 10:56

本文选题：沥青混凝土 + 导电特性　；参考：《武汉理工大学》2014年博士论文

【摘要】：随着我国沥青混凝土路面建设的飞速发展，路面的养护与安全问题受到广泛的重视，对养护时机的判断，冬季的融雪化冰的研究已经成为国内外沥青混凝土材料领域的研究热点。近些年来，导电沥青混凝土以其具有良好的压敏性能，自愈合性能和电热性能受到广泛的关注并进行了相关研究。目前，导电沥青混凝土的很多制备技术，性能参数测试都是在室内试验的基础上完成的，这在一定程度上限制了导电沥青混凝土在工程实践中的应用。因此，探明导电沥青混凝土导电特性与原材料，外界条件的关系，揭示导电填料与沥青的界面行为，研究导电沥青混凝土老化后的性能，提出导电沥青混凝土的施工关键技术对导电沥青混凝土的推广与应用具有重要的理论指导意义。本文从原材料与外界条件出发，研究了沥青、导电填料和集料对导电特性的影响，揭示了不同压力、不同温度、不同湿度条件下的导电特性变化规律；利用X荧光分析(XRF)、扫描电镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、紫外可见光谱(UV-Vis)、接触角测量等技术手段表征了导电填料与沥青的界面行为；通过室内加速老化的方法，测试老化后的导电沥青混凝土的路用性能与电学性能，建立老化衰减模型，评价其服役行为；提出了导电沥青混凝土的拌和、运输、摊铺、碾压技术，并测试了近2年的电学性能与路用性能的变化。主要结论如下：（1）为了获得优良的导电特性，集料的个体特征方面，其长宽比应小于2:1，偏心率小于0.78为宜；集料的组合特征方面，Superpave与AC级配具有类似的试验结果，都具有良好的空隙和连通性。此外，鳞片石墨的表面间距与导电沥青混凝土的矿料间隙率（VMA），空隙率（VV），石墨的体积掺量，石墨的粒径有关，，并建立了导电沥青混凝土的电阻模型。（2）在恒力作用下导电沥青混凝土出现电阻蠕变；在变力的作用下导电沥青混凝土出现压敏现象。这与导电通路的形成，石墨-沥青-集料界面效应，微裂缝效应有关。（3）在不同的温度、湿度作用下，导电沥青混凝土的电阻随着温度、湿度而变化，表现出一定的温度、湿度效应，表明导电沥青混凝土经过多年的服役后，其电阻不单反映当时的内部疲劳损伤情况，还会根据当地的气候条件而发生不可逆的增加。（4）鳞片石墨表面介孔多，孔隙发达，比表面积大，沥青可在其表面形成较为发育的吸附溶化膜。沥青与石墨的粘附功随着沥青的温度升高而增加。鳞片石墨在沥青中拌和时，处于先吸热后放热的过程。（5）石墨-沥青分散系统是一个松散的均匀堆积系统，导电沥青胶浆中导电网络的电阻主要就是石墨颗粒间的电阻。鳞片石墨颗粒在酸环境下ζ电位均为正值，表明石墨-沥青体系的导电网络是比较稳定的体系。（6）经过室内加速老化后，导电沥青混凝土与普通沥青混凝土相比，路用性能接近。导电沥青混凝土的电学性能的衰减是由上至下的，由外而内的。利用时温等效原理建立了导电沥青混凝土的在135℃老化条件下的路用性能与电学性能的老化衰减模型。（7）建立了导电沥青混凝土的拌和模型，提出了将石墨加入技术；确定了导电沥青混凝土的拌和工艺。采用“三明治”结构的电极形式，提出了导电沥青混凝土的摊铺与碾压关键技术。铺筑的导电沥青混凝土路面具有良好的路用性能与电学性能，满足沥青混凝土路面损伤诊断，融雪化冰的需求。
[Abstract]:With the rapid development of the construction of asphalt concrete pavement in China, the maintenance and safety of the pavement have been widely paid attention to. The study of the snow melting ice in winter has become a hot spot in the field of asphalt concrete materials at home and abroad. In recent years, the conductive asphalt concrete has good pressure sensitive performance, and it has been used in recent years. The healing properties and electrothermal properties are widely concerned and related research. At present, a lot of preparation techniques of conductive asphalt concrete and performance parameters are tested on the basis of laboratory tests. This restricts the application of conductive asphalt concrete in engineering practice. Therefore, it is clear that the conductive asphalt concrete is explored. The relationship between the conductive properties and the raw material and the external conditions reveals the interface behavior of the conductive filler and the asphalt, and studies the performance of the aging of the conductive asphalt concrete. The key construction technology of the conductive asphalt concrete is of great theoretical significance to the popularization and application of the conductive asphalt concrete.
In this paper, the effects of asphalt, conductive fillers and aggregates on the electrical conductivity are studied from raw materials and external conditions, and the change rules of electrical properties under different pressure, temperature and humidity are revealed. X fluorescence analysis (XRF), scanning electron microscopy (SEM), X ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV visible light are used. Spectrum (UV-Vis), contact angle measurement and other technical means to characterize the interfacial behavior of conductive filler and asphalt; through indoor accelerated aging method, test the road performance and electrical properties of aging conductive asphalt concrete, establish an aging attenuation model, evaluate its service behavior, and put forward the mixing, transportation and paving of conductive asphalt concrete. The rolling technology and the changes of electrical performance and road performance in recent 2 years were tested.
(1) in order to obtain excellent electrical properties and the individual characteristics of aggregate, the ratio of length to width should be less than 2:1 and the eccentricity is less than 0.78. In combination with aggregate characteristics, Superpave and AC gradation have similar experimental results, and have good gap and connectivity. In addition, the surface spacing of the flake graphite and the mineral material of the conductive asphalt concrete The gap rate (VMA), void fraction (VV), volume of graphite and particle size of graphite are related to the resistance model of conductive asphalt concrete.
(2) the resistance creep of the conductive bituminous concrete under the action of constant force, and the pressure sensitive phenomenon of the conductive asphalt concrete under the action of variable force, which is related to the formation of the conduction channel, the graphite asphalt aggregate interface effect and the micro crack effect.
(3) under the action of different temperature and humidity, the resistance of the conductive asphalt concrete varies with the temperature and humidity. It shows a certain temperature and humidity effect. It shows that after years of service, the resistance of the conductive asphalt concrete is not only reflected the internal fatigue damage at that time, but also the irreversible increase according to the local climate conditions. Add.
(4) the surface of the flake graphite has a large mesoporous surface, which has a developed pore and a larger surface area. The asphalt can form a more developed adsorption and solubility film on its surface. The adhesion work of the pitch and graphite increases with the increase of the temperature of the asphalt. When the scale graphite is mixed in the asphalt, it is in the process of heat absorption and heat release.
(5) the graphite asphalt dispersion system is a loose and uniform accumulation system. The resistance of the conductive network in the conductive asphalt mortar is mainly the resistance between the graphite particles. The zeta potential of the scale graphite particles in the acid environment is positive, indicating that the conductive network of the graphite asphalt system is a relatively stable system.
(6) after accelerated aging, the performance of conductive asphalt concrete is close to that of ordinary asphalt concrete. The attenuation of electrical properties of conductive asphalt concrete is from top to bottom, from outside to inside. Using the principle of time temperature equivalence, the road performance and electrical properties of conductive asphalt concrete under 135 centigrade aging conditions are established. Attenuation model.
(7) the mixing model of conductive asphalt concrete was set up, the graphite adding technology was put forward, and the mixing process of the conductive asphalt concrete was determined. The key technology of the spreading and rolling of the conductive asphalt concrete was put forward by using the electrode form of "sandwich" structure. The pavement performance of the paved conductive asphalt concrete pavement was good and the performance of the pavement was good. Electrical properties meet the needs of damage diagnosis and snow melting and ice melting of asphalt concrete pavement.
【学位授予单位】：武汉理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU528

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