温拌再生沥青结合料融合体系的纳观粘附特性及其微观机理研究

Blending system is composed of reclaimed asphalt pavements (RAP) binder, virgin asphalt, rejuvenating agent and warm mixture asphalt (WMA) additives, which has a critical effect on the moisture susceptibility of warm mix asphalt mixtures containing RAP. However, the uncertainty of the blending system state under the multi-factor coupling conditions has led to two major bottlenecks in the current research on the influence mechanism of the adhesion, i.e., the accurate characterization of the nano-scale adhesion and the simultaneous interpretation of the microscopic mechanism. To solve these problems, this research project aims to carry out a systematic study on the nano-scale adhesion and microscopic mechanism of blending system in warm mix asphalt mixtures containing RAP. There are four main themes in the project. Firstly, the in-situ characterization method of nano-scale adhesion of blending system will be constructed using atomic force microscopy (AFM), which would be verified based on the surface free energy theory. Secondly, the selection model of raw material composition of warm mix asphalt containing RAP will be established using nano-scale adhesion index based on research conclusion in effect of raw material composition on the nano-scale adhesion of deep blending system by developed AFM in-situ characterization technique. Thirdly, the influence of the complex factors including raw materials, mixing and aging conditions on the nano-scale adhesion of blending asphalt and RAP aggregate interface transition zone will be analyzed. Fourthly, the formation mechanism of the microstructure of the blending system and its influence mechanism on the nano-scale adhesion were studied using AFM, GPC and FTIR. The research results from this project will provide theoretical and technical evidence to evaluate the adhesion of warm mix asphalt binders containing RAP and improve the moisture susceptibility of warm mix asphalt mixtures containing RAP.

回收沥青与新沥青、再生剂和温拌剂构成的融合体系是影响温拌再生沥青混合料水敏感性的关键。然而，多因素耦合条件下融合体系状态的不确定性使得当前的粘附性影响机制研究存在两大瓶颈：纳观粘附性的精准表征、微观机理的同步阐释。为此，本项目拟开展温拌再生沥青融合体系纳观粘附性及其微观机理的系统研究。具体内容包括：构建基于原子力显微镜（AFM）的融合体系纳观粘附性原位表征方法并基于表面能理论进行可靠性验证；采用AFM原位表征技术研究原材料组成对深度融合体系纳观粘附性的作用规律，建立基于纳观粘附指标的温拌再生沥青原材料组成选择模型；研究原材料、拌合与老化条件等耦合因素对融合沥青与“黑石头”界面过渡区纳观粘附性的影响；采用AFM、GPC与FTIR研究融合体系微观结构的形成机制及其对纳观粘附性的影响机理。研究成果将为客观评价温拌再生沥青的粘附性和改善温拌再生沥青混合料的水敏感性奠定理论与技术基础。

回收沥青与新沥青、再生剂和温拌剂构成的融合体系是影响温拌再生沥青混合料水敏感性的关键。然而，多因素耦合条件下融合体系状态的不确定性使得当前的黏附性影响机制研究存在两大瓶颈：纳观黏附性的精准表征、微观机理的同步阐释。为此，本项目以温拌再生沥青融合体系纳观黏附性及其微观机理为研究对象，采用原子力显微镜（AFM）原位表征、表面自由能理论、拉拔试验等方法研究了原材料组成与制备条件对再生沥青深度融合体系纳观黏附性的作用规律，并结合微观试验探明了再生沥青融合体系微观结构的形成机制及其对纳观黏附性的影响机理。取得了一些原创性成果：1）研发了一款针对于西北强紫外线地区老化沥青的再生剂，阐明了原材料组成、制备工艺参数和老化程度对温拌再生沥青流变特性的影响规律；2）基于表面自由能理论与拉拔试验探讨了温拌再生沥青表面能和黏附性的影响机制，发现了粘聚功与测力延度具有良好的相关性，并揭示了路易斯酸γa＋对温拌再生沥青黏附性的影响规律；3）基于AFM量化表征了原材料组成对温拌再生沥青的粗糙度、形貌图和相图等微观结构信息的影响规律，探明了沥青微观结构形态分布特征对沥青融合体系纳观黏附性的作用规律，建立了宏-介-微三元多尺度的温拌再生沥青黏附性能的相关性，确定了纳米尺度上定量表征温拌再生沥青黏附性能的指标；4）结合傅里叶红外光谱（FTIR）、凝胶渗透色谱（GPC）和分子动力学（MD）等方法表征了温拌再生沥青微观结构变化和分子量分布状态，建立了微观结构和分子量与宏观性能之间的内在联系，明确了沥青融合体系微观结构的形成机制及其对纳观黏附性的影响规律。本项目的成功实施为本学科研究发展开拓了新的思路和方法，为客观评价温拌再生沥青的黏附性和改善温拌再生沥青混合料的水敏感性奠定理论与技术基础。