水分在泡沫温拌沥青混合料中的迁移规律与作用机理

Foam warm asphalt mix is a "green" construction technology developed rapidly in recent years. The essence of foam warm asphalt mix is to reduce the construction temperature through injecting water during mixing process to lower the required temperature for mixing. As a result of temperature reduction, many benefits can be achieved, such as energy saving, emission reduction, and contructability. The premise of using warm mix is that the pavement performance will not be negatively affected . However, due to the short time of the technological development, some of the key technical issues have not been clearly understood or resolved. The issues include, but are not limited to,(1) how does the moisture in the foam warm asphalt mix during pumping in theproduction process migrate? (2) how does the residual moisture in the foam warm mix influence the foam asphalt mixture performance? These questions restrict the development and progress of the technology. This research mainly aims to resolve some of key issues such as tracing migration patterns of moisture in warm asphalt mixture, finding interface behavior between aggregate and asphalt during different construction process, and revealing the microscopic mechanism of moisture in the foam warm asphalt mixture ,thus providing a fundamental theoretical support for the promotion of this technology. First, the research will identify migration patterns and microscopic characteristics of moisture in foam warm asphalt mixture through micro-analysis techniques; Secondly, the research will study viscosity reduction mechanism and interface behavior of moisture in the foam warm mix asphalt using molecular thermodynamics theory; Finally, the research will establish the nanoscale mechanical molecular mechanics model to simulate the diffusion behavior and the mechanical response of the moisture in the foam warm asphalt mixture and to analyze the mechanism of water on the foam warm asphalt mix performance. This research project is expected to solve some of the key issues that hinder the application and progress of foam warm asphalt mix. This project aims to achieve energy conservation, and at the same time, to ensure the long-term performance of the pavement with good prospects of promotion because of significant social and economic benefits.

泡沫温拌沥青技术是近年来兴起的一项"绿色"筑路技术，其实质是在不影响路面质量的前提下，通过注入水分降低施工温度，实现节能、减排的目的。但由于对关键技术-水分在泡沫温拌沥青混合料生产过程中的迁移规律及作用机理的研究不够深入，制约了该项技术的推广应用。本课题的研究旨在追踪水分在泡沫温拌沥青混合料中的迁移规律和界面行为，揭示水分在泡沫温拌沥青混合料中的微观作用机理，为泡沫温拌技术的推广提供基础的理论支撑。首先，通过微观分析技术追踪水分在温拌沥青混合料中的迁移规律和微观特征；其次，研究水分在泡沫温拌沥青混合料中的降粘机理和界面行为；最后，建立纳米级分子力学模型，对水分在泡沫温拌沥青混合料中的扩散行为和力学响应进行模拟，分析水分对泡沫温拌沥青混合料性能的影响机理。课题的研究有望解决阻碍泡沫温拌沥青混合料应用的核心技术，在实现节能减排的同时，保证混合料的长期性能，具有显著的社会效益和经济效益。

泡沫温拌沥青技术时近几年兴起的一项真正的“绿色”筑路技术，其实质是在不影响路面质量的前提下，通过注入水分降低施工温度，实现节能、减排的目的。但由于对关键技术-水分在泡沫温拌沥青混合料生产过程中的迁移规律及作用机理的研究不够深入，水分的加入是否会损害沥青混合料的路用性能、是否会破坏沥青与集料的界面力学性能尚未可知，限制了泡沫温拌技术的推广应用。.本课题通过微观分析技术追踪了水分在泡沫温拌沥青混合料中的状态及迁移规律，考察了泡沫温拌沥青降粘效果的影响因素，研究了水分在泡沫温拌沥青混合料中的降粘机理，采用电化学阻抗和界面表明自由能研究了水分在泡沫温拌沥青混合料中的界面行为，最后建立分子动力学模型，对水分在泡沫温拌沥青混合料中的扩散行为和力学响应进行了模拟，分析了水分对泡沫温拌沥青混合料性能的影响机理。.通过本课题的研究发现，泡沫沥青以“油泡”的形式存在，在高温条件下，“油泡”不断破裂变小，水分不断散失。泡沫温拌沥青混合料经过拌合、运输、摊铺及碾压后其水分含量小于0.1%。水分的加入并没有引起沥青化学结构的变化，也没有新的化学官能团的产生。水分在泡沫沥青中的界面行为主要体现在它对沥青粘聚性能的影响，而对于沥青-集料的黏附性能影响不大，即其对沥青混合料的水稳定性损害不大。泡沫温拌沥青混合料中残留水分与外界水对其混合料的影响机理不同。.本课题的明确了水分在泡沫温拌沥青混合料中的迁移规律和界面行为，解决了发泡水的加入是否对沥青混合料产生负面影响的困扰，在实现节能减排降低施工温度的同时，保证了混合料的长期性能，具有显著的社会效益和经济效益。