Yang Jiangang, Luo Luhua, Gao Jie, Xu Jing, He Chengping
School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China.
Institute of Road Engineering, East China Jiaotong University, Nanchang 330013, China.
Materials (Basel). 2022 Jan 5;15(1):380. doi: 10.3390/ma15010380.
China's highway asphalt pavement has entered the stage of major repair, and improving the utilization rate of recycled asphalt pavement (RAP) is the main issue. The key link affecting the performance of recycled asphalt mixtures is the regeneration of aged asphalt, and the effect of the regenerant dosing on the high-temperature performance and viscosity of aged asphalt is the main content to be studied in this research. The aging behavior of asphalt seriously affects the roadworthiness of asphalt mixtures. In this study, we investigated the effect of changes in the microscopic properties of the aged asphalt on its viscosity properties during regeneration using gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM) as well as Brinell viscosity tests. This study simulated asphalt aging by the RTFOT test, and then we obtained an aged asphalt with a needle penetration of 30. We prepared different regenerated asphalts by adding regeneration agent with doses of 2%, 4%, and 6% to the aged asphalt. The results showed that the regeneration agent could effectively reduce the viscosity of the aged asphalt, which can play a positive role in improving the construction and ease of the aged asphalt. Rejuvenation agents affected the aging asphalt sulfoxide and carbon group indices. Moreover, rejuvenation agents can also significantly reduce the intensities of their characteristic functional group indices. The results of the AFM test showed that the increase in the dose of regeneration agent increased the number of the asphalt bee-like structures and decreased the area of individual bee-like structures. The results of the GPC test were consistent with the results of the AFM test, and the increase in the dose of regeneration agent reduced the asphalt macromolecule content. The viscosity properties and microstructure of the aged asphalt changed positively after the addition of the regeneration agent, indicating that the regeneration agent had a degrading and diluting effect on macromolecules.
中国公路沥青路面已进入大修阶段，提高再生沥青路面（RAP）利用率成为主要问题。影响再生沥青混合料性能的关键环节是老化沥青的再生，再生剂剂量对老化沥青高温性能和粘度的影响是本研究的主要研究内容。沥青的老化行为严重影响沥青混合料的路用性能。本研究采用凝胶渗透色谱法（GPC）、傅里叶变换红外光谱法（FTIR）、原子力显微镜法（AFM）以及布氏粘度试验，研究了老化沥青微观性能变化对其再生过程中粘度性能的影响。本研究通过RTFOT试验模拟沥青老化，然后得到针入度为30的老化沥青。通过向老化沥青中添加剂量为2%、4%和6%的再生剂制备了不同的再生沥青。结果表明，再生剂能有效降低老化沥青的粘度，对改善老化沥青的施工性能和施工便利性具有积极作用。再生剂影响老化沥青的亚砜和碳基团指数。此外，再生剂还能显著降低其特征官能团指数的强度。AFM试验结果表明，再生剂剂量增加，沥青蜂状结构数量增多，单个蜂状结构面积减小。GPC试验结果与AFM试验结果一致，再生剂剂量增加，沥青大分子含量降低。添加再生剂后，老化沥青的粘度性能和微观结构发生了积极变化，表明再生剂对大分子具有降解和稀释作用。
