针对再生剂扩散和再生沥青性能预测模型不统一、影响机理不明确的问题，基于自由体积理论，研究再生剂-沥青复合体系扩散行为表征方法和影响机制，预测再生沥青关键性能。首先，根据沥青和再生剂官能团分布的实验测定以及自由体积特征的分子动力学模拟，采用基团贡献人工神经网络集成法，建立沥青自由体积特征量化方法。其次，考虑再生剂-沥青体系组分间交互作用，构建基于自由体积理论的再生剂扩散系数计算模型，解析沥青与再生剂化学结构、性能参数、相互作用、以及温度等因素与再生剂扩散过程的内在关系。采用正电子湮灭和荧光追踪技术，测试沥青自由体积分布和再生剂扩散系数，修正构建的模型。最后，根据沥青黏度和氧分子扩散的自由体积依赖特性，建立扩散进程与再生沥青黏度和抗老化性能间关系，预测再生沥青性能随扩散过程演化特征。项目通过构建再生沥青微观结构-扩散行为-宏观性能间多元关系，为再生剂优选和开发提供理论基础。

The quantitative characterization method and influence mechanism of asphaltic rejuvenator diffusion are studied based on the free volume theory aiming at the problems of inconsistent prediction models of diffusion and recycled asphalt performance. The results can be used to predict key performance of recycled asphalt. A method for quantifying asphaltic free volume is established using the group contribution artificial neural network integration approach based on the accurate determination of functional groups distribution of asphalt and molecular dynamics simulation of free volume characteristics. The model for the diffusion coefficient of the rejuvenator based on the free volume theory is constructed to analyze the influence of chemical structure, performance parameters, interactions, and temperature on the diffusion process. The free volume distribution of the asphalt and the diffusion coefficient of the rejuvenator are tested by positron annihilation and fluorescence tracing techniques to modify the models. The influence of the diffusion process on the viscosity and aging resistance of recycled asphalt is established to determine the evolution characteristics of recycled asphalt performance with the diffusion process based on the free volume-dependent of asphalt viscosity and oxygen molecule diffusion. The project provides the theoretical basis for the optimization and development of asphaltic rejuvenator by constructing a mechanism of microstructure-diffusion behavior-macro performance correlation for recycled asphalt.