沥青再生剂扩散系数模型及其影响因素

Diffusion Coefficient Model and Impact Analysis of Different Asphalt Rejuvenators

为满足道路养护对高效沥青再生剂的需求,研究基于对自由体积理论的分析建立再生剂扩散系数预测模型,结合基团贡献法、参数拟合法计算模型参数,通过模拟方法验证模型有效性。模拟及预测扩散系数对比表明,扩散系数模型能够有效预测再生剂在老化沥青中的扩散系数。同时,研究基于模型对扩散行为的影响因素进行分析,探究了分子间相互作用、温度与再生剂扩散行为之间的关系。结果显示:芳香分再生剂与沥青分子间的相互作用比饱和分再生剂高,扩散速度较快;随温度的升高,饱和分再生剂的分子加速扩散,温度达到400 K后,饱和分再生剂的扩散系数大于芳香分再生剂。以上结果说明,在选用再生剂时,需同时关注温度及内部分子的化学结构对再生效率的影响。

In order to meet the demand for efficient asphalt rejuvenators in road engineering,the research established a prediction model for the behavior of rejuvenator according to free volume theory.Parameters in the model were calculated based on the functional group contribution and parameter fitting method.To verify the accuracy,a simulation method was adopted to get the simulated diffusion values.The results of the diffusion coefficients from different methods showed that the diffusion coefficient model could effectively predict the diffusion coefficient of rejuvenators in aged asphalt.The research concurrently examined the variables affecting diffusion activity,using the formulated model to analyze how intermolecular interactions,temperature,and the diffusion coefficient were interconnected.Results showed that the intermolecular interaction between the aromatic-based rejuvenator and asphalt was higher,and the diffusion speed of the aromatic-based rejuvenator was faster.With the increase in temperature,the molecular diffusion of the saturated fraction regenerant accelerated.When the temperature is 400 K,the diffusion coefficients of the saturate-based rejuvenators are greater than that of the aromatic-based rejuvenator.The above results indicate that when selecting rejuvenators,attention should be paid to the influence of temperature and chemical structure of internal molecules on rejuvenation efficiency.