Abstract:

Interface diffusion behavior between asphalt rejuvenators and aged asphalt is the key factor affecting hot recycling efficiency, process level and service performance of reclaimed asphalt pavement. Simulation methods of diffusion state of rejuvenators into aged asphalt were systematically reviewed including soaking method, layered extraction technology, surface wettability method, tracer method and molecular dynamics simulation method. The advantages and disadvantages of existing research methods were comparatively analyzed, on the basis of which, characterization methods and evaluation parameters of different time history diffusion states were summarized. The characteristics and applicability of various evaluation methods were discussed. The future research direction of characterization methods of diffusion behavior of asphalt rejuvenators was prospected. Research results showed that diffusion samples prepared based on the surface wettability method had unique methods and indicators for characterizing diffusion states, which were suitable for evaluating interface characteristics and instant diffusion rate of rejuvenators wetting aging asphalt. Tracer technologies could capture the slice blending status of diffusion samples. Diffusion characterization methods of soaking method and layered extraction technology were more diversified. The combination of molecular dynamics simulation and diffusion test considering thermodynamic parameters was the main pathway to study diffusion behavior and driving force mechanism of asphalt rejuvenators. In the future, the research on the lateral diffusion behavior of asphalt rejuvenators along the asphalt film surface should be strengthened, and a variety of contact modes between rejuvenators and aged asphalt should be considered. The diffusion kinetic model considering time-temperature attenuation effect needed to be established, which provided a theoretical basis and reference for scientifically determining process parameters of hot recycled asphalt pavement.

Key words: recycled asphalt pavement, rejuvenators, diffusion behavior, interface, characterization method, evaluation parameters

摘要：

沥青再生剂与老化沥青界面的扩散行为是影响废旧沥青路面的热再生效率、工艺水平以及服役性能的重要因素。本文系统综述了再生剂在老化沥青中扩散状态的模拟方法，包括浸泡法、分层萃取技术、表面润湿法、示踪技术和分子动力学模拟方法，对比分析了现有研究方法的优缺点，在此基础上归纳了不同扩散时程状态的表征方法及评价参数，讨论了各种评价方法的特点及适用性，并展望了沥青再生剂扩散行为表征方法的研究方向。基于表面润湿法获取的扩散试样有其独特的扩散状态表征方法和指标，适用于评价再生剂润湿老化沥青界面的特性、即时扩散速率；示踪技术能够捕捉扩散试样的切片混溶性状；浸泡法、分层萃取技术的扩散性状表征方法更加多元；采用计入热力学参数的分子动力学模拟与扩散试验相结合的方法是研究沥青再生剂扩散行为、驱动力机制的主要途径。未来应加强对沥青再生剂沿沥青膜表面的横向扩散行为的研究，计入再生剂与老化沥青的多种接触模式，建立考虑时温衰减效应的扩散动力学模型，为科学确定热再生沥青路面工艺参数提供理论依据和参考。

关键词: 再生沥青路面, 再生剂, 扩散行为, 界面, 表征方法, 评价参数