Guo Fei, Li Xiaoyu, Wang Ziran, Chen Yijun, Yue Jinchao
School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou 450001, China.
Henan Central Construction Engineering Co., Ltd., Zhengzhou 450016, China.
Polymers (Basel). 2024 Aug 30;16(17):2482. doi: 10.3390/polym16172482.
To comprehensively understand the impact of various environmental factors on the self-healing process of graphene-modified asphalt, this study employs molecular dynamics simulation methods to investigate the effects of aging degree (unaged, short-term aged, long-term aged), asphalt type (base asphalt, graphene-modified asphalt), healing temperature (20 °C, 25 °C, 30 °C), and damage degree (5 Å, 10 Å, 15 Å) on the self-healing performance of asphalt. The validity of the established asphalt molecular models was verified based on four physical quantities: density, radial distribution function analysis, glass transition temperature, and cohesive energy density. The simulated healing time for the asphalt crack model was set to 200 ps. The following conclusions were drawn based on the changes in density, mean square displacement, and diffusion coefficient during the simulated healing process under different influencing factors: Dehydrogenation and oxidation of asphalt molecules during the aging process hinder molecular migration within the asphalt crack model, resulting in poorer self-healing performance. As the service life increases, the decline in the healing performance of graphene-modified asphalt is slower than that of base asphalt, indicating that graphene-modified asphalt has stronger anti-aging properties. When the vacuum layer in the asphalt crack model is small, the changes in the diffusion coefficient are less pronounced. As the crack width increases, the influence of various factors on the diffusion coefficient of the asphalt crack model becomes more significant. When the crack width is large, the self-healing effect of asphalt is more dependent on these influencing factors. Damage degree and oxidative aging have a more significant impact on the healing ability of graphene-modified asphalt than healing temperature.
为全面了解各种环境因素对石墨烯改性沥青自愈过程的影响，本研究采用分子动力学模拟方法，研究老化程度（未老化、短期老化、长期老化）、沥青类型（基质沥青、石墨烯改性沥青）、愈合温度（20℃、25℃、30℃）和损伤程度（5Å、10Å、15Å）对沥青自愈性能的影响。基于密度、径向分布函数分析、玻璃化转变温度和内聚能密度这四个物理量，验证了所建立的沥青分子模型的有效性。将沥青裂纹模型的模拟愈合时间设置为200 ps。根据不同影响因素下模拟愈合过程中密度、均方位移和扩散系数的变化，得出以下结论：老化过程中沥青分子的脱氢和氧化阻碍了沥青裂纹模型内分子的迁移，导致自愈性能较差。随着使用寿命的增加，石墨烯改性沥青愈合性能的下降比基质沥青慢，表明石墨烯改性沥青具有更强的抗老化性能。当沥青裂纹模型中的真空层较小时，扩散系数的变化不太明显。随着裂纹宽度的增加，各种因素对沥青裂纹模型扩散系数的影响变得更加显著。当裂纹宽度较大时，沥青的自愈效果更依赖于这些影响因素。损伤程度和氧化老化对石墨烯改性沥青愈合能力的影响比愈合温度更显著。
