Long Zhengwu, You Lingyun, Xu Fu, Tang Xianqiong, Ding Yanhuai, Khanal Ashok, Miao Yu
School of Civil and Hydraulic Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei Province, China.
School of Civil and Hydraulic Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei Province, China.
J Colloid Interface Sci. 2022 Dec 15;628(Pt A):891-909. doi: 10.1016/j.jcis.2022.08.014. Epub 2022 Aug 5.
Coastal asphalt pavements are highly susceptible to sea salt erosion, which leads to a significant decrease in road performance and durability. However, the interface micro-adhesion mechanism of the asphalt-aggregate composites under chloride ion erosion is still not fully understood. Herein, using the silica microsphere Atomic Force Microscopy (AFM) modified tip and asphalt sample with chloride ions as a surface, we report the effect mechanism of chloride ion erosion on the interface adhesion behavior of asphalt-silica composites by AFM from the atomistic scale. The chloride ion erosion mechanism was further supported by molecular dynamics (MD) simulations. Due to the erosion effect of chloride ions, the structure evolution of the asphalt film surface will occur, and the weak adhesion gradient zone will be formed on the surface of the asphalt film. The concentration effect of chloride ions accelerates the formation of adhesion gradient zones, which are unstable and evolve over erosion time. Due to the presence of these adhesion gradient zones, water molecules will more easily penetrate the asphalt membrane and enter the asphalt-silica interface through adsorption and diffusion, thereby weakening the interface adhesion ability between the asphalt and the aggregate. Furthermore, the distribution and diffusion of asphalt fractions on the aggregate surface also affect the adhesion behavior evolution of asphalt-silica composites induced by chloride ion erosion. The evolution in the spatial distribution of fractions may be related to the formation of interfacial adhesion gradient zones. This study outcome has important theoretical significance for promoting the sustainability of asphalt pavements and for guiding pavement deicing.
滨海沥青路面极易受到海盐侵蚀，这会导致道路性能和耐久性显著下降。然而，氯离子侵蚀作用下沥青-集料复合材料的界面微黏附机制仍未完全明晰。在此，我们使用二氧化硅微球原子力显微镜（AFM）修饰探针以及以氯离子为表面的沥青样品，从原子尺度通过AFM揭示了氯离子侵蚀对沥青-二氧化硅复合材料界面黏附行为的作用机制。分子动力学（MD）模拟进一步支持了氯离子侵蚀机制。由于氯离子的侵蚀作用，沥青膜表面会发生结构演变，且在沥青膜表面会形成弱黏附梯度区。氯离子的浓度效应加速了黏附梯度区的形成，这些区域不稳定且会随侵蚀时间而演变。由于这些黏附梯度区的存在，水分子将更容易穿透沥青膜并通过吸附和扩散进入沥青-二氧化硅界面，从而削弱沥青与集料之间的界面黏附能力。此外，沥青组分在集料表面的分布和扩散也会影响氯离子侵蚀引起的沥青-二氧化硅复合材料黏附行为演变。组分空间分布的演变可能与界面黏附梯度区的形成有关。本研究成果对于促进沥青路面的可持续性以及指导路面除冰具有重要的理论意义。
