表面修饰粉煤灰对沥青路用性能的影响
Effect of surface？？modified fly ash on engineering performance of asphalt

针对粉煤灰？擦で嘀？间的相互作用问题，借助表面修饰技术，采用NaOH碱性溶液和KH550偶联剂对4种不同来源的粉煤灰进行处理；在此基础上，借助动态剪切流变试验、弯曲梁流变试验对不同表面修饰技术下粉煤灰沥青胶浆的高温、低温性能进行测试，最后借助X射线衍射、氮吸附测试(BET)和红外光谱试验进行表面修饰技术对粉煤灰的改性机理的微观研究。研究结果表明：除个别样品外，大部分NaOH和KH550偶联剂表面修饰的粉煤灰降低了沥青胶浆的弹性，提高了浆体的抗车辙能力；经NaOH表面修饰后，FA？？3沥青浆体的低温抗裂性能最差，FA？？4沥青胶浆的低温抗裂性能最好；KH550偶联剂表面修饰后，粉煤灰与沥青浆体之间不存在明显的化学反应，但没有证据表明不存在轻微的化学偶联作用；NaOH表面修饰没有产生新的化学相，但超细粉煤灰表面活性点位多，NaOH对其表面修饰较为明显，比表面积和孔容积均明显增多，比KH550偶联剂表面修饰作用更为明显。经表面修饰技术改性后粉煤灰作为沥青混凝土填料，可有效提高沥青混凝土的综合路用性能，为粉煤灰“变废为宝”再利用提供了理论依据。
This study aims to determine the interaction between fly ash and asphalt. The surface？？modification technology was adopted, and four kinds of fly ash from different sources were treated with NaOH solution and KH550 coupling agent. Subsequently, the dynamic shear and bending beam rheological tests were used to assess the high？？and low？？temperature properties of the fly ash asphalt mortar under different surface？？modification techniques. Finally, the modification mechanism owing to fly ash was studied using X？？ray diffraction, the Brunauer？？Emmett？？Teller (BET) adsorption test, and infrared spectroscopy. The results show that with the exception of some individual samples, NaOH and KH550 modified fly ash reduce the elasticity of asphalt mortar, and improve its rutting resistance. After NaOH modification, the low？？temperature crack resistance of FA？？3 asphalt mortar is found to be the worst, the FA？？4 asphalt mortar exhibit the best anti？？cracking performance at low temperature. There is no obvious chemical reaction between the fly ash and the asphalt after KH550 coupling agent modification, but there is also no evidence to indicate that there is no slight chemical coupling interaction between KH550, fly ash, and asphalt. There is no new phase separation after NaOH treatment, however, NaOH modify the surface of the superfine powder with more active points, i.e., the specific surface area and volume fraction is enhanced by the NaOH solution. This surface？？modification effect is more obvious than that of KH550. The findings in this article indicated that as a filler, modified fly ash can effectively improve the road performance of asphalt concrete as well as provide a guidance for the reuse of fly ash. 3 tabs, 10 figs, 29 refs