Zhang Xuemei, Hoff Inge, Saba Rabbira Garba
Department of Civil and Environmental Engineering, Norwegian University of Science and Technology, Høgskoleringen 7A, 7491 Trondheim, Norway.
Norwegian Public Roads Administration, Abels Gate 5, 7030 Trondheim, Norway.
Materials (Basel). 2021 Aug 29;14(17):4911. doi: 10.3390/ma14174911.
Acid rain as an important environmental issue has a negative impact on bitumen performance, thereby shortening the service life of asphalt pavements. Thus, this research aims to investigate the response of bitumen to acid rain and its deterioration mechanism. For this purpose, the simulated acid rain was prepared to erode neat bitumen and short-term aged bitumen. The hydrogen ion concentration of the acid rain, and the morphological, physical, chemical, and rheological properties of the bitumen were evaluated by means of a pH meter, scanning electron microscopy, physical tests, Fourier transform infrared radiation with attenuated total reflectance, and dynamic shear rheometer. The results showed that bitumen properties were severely affected by acid rain, and the changes in bitumen properties were highly related to the erosion time, leading to a reduction in pH value by 0.2 of residual acid rain, rougher bitumen surface, and stiffer bitumen with more oxygen-containing functional groups and fewer carbonyl acid groups (around 10% decrement) after 90 days erosion. These changes contributed to two deterioration mechanisms: oxidation and dissolution of carbonyl acid. Oxidation and dissolution are, respectively, the dominant actions for neat bitumen and aged bitumen during the erosion process, which eventually leads to various responses to acid rain.
酸雨作为一个重要的环境问题，会对沥青性能产生负面影响，从而缩短沥青路面的使用寿命。因此，本研究旨在探究沥青对酸雨的响应及其劣化机制。为此，制备了模拟酸雨来侵蚀纯沥青和短期老化沥青。通过pH计、扫描电子显微镜、物理试验、衰减全反射傅里叶变换红外光谱以及动态剪切流变仪来评估酸雨的氢离子浓度以及沥青的形态、物理、化学和流变性能。结果表明，沥青性能受到酸雨的严重影响，沥青性能的变化与侵蚀时间高度相关，经过90天的侵蚀后，残余酸雨的pH值降低了0.2，沥青表面更粗糙，沥青变硬，含氧化官能团增多，羰基酸基团减少（减少约10%）。这些变化导致了两种劣化机制：羰基酸的氧化和溶解。氧化和溶解分别是侵蚀过程中纯沥青和老化沥青的主要作用，最终导致沥青对酸雨产生各种响应。
