沥青与集料界面粘附性自愈合的机理、评价与增强

As a binder, asphalt has two intrinsic properties: adhesion and self-healing. To have a comprehensive and systematic understanding of its fundamental qualities, these two properties should be connected with each other, that is, adhesive self-healing. However, most studies are focused on the cohesive self-healing which causes the closure of cracks in the asphalt material itself, while there are few researches on the adhesive self-healing property which promotes the re-adhesion between the asphalt binder and aggregate. This impedes the study of asphalt adhesive property and also results in the confusion about the asphalt self-healing researches. This project will mainly adopt the Atomic Force Microscope and Surface Energy Analysis to analyze the adhesive self-healing mechanism on the micro-scale, and use the CT-scan and other phenomenological approaches to investigate the progresses and evolution rule of the adhesive self-healing on the meso-scale. Then, the current pull-off test and direct shear test will be modified to propose the method to evaluate the asphalt adhesive self-healing capability with the validation from the hamburg wheel tracking test and fatigue beam test on the macro-scale. Based on these results, the expression equation will be put forward, the influential factors will be studied and the adhesive self-healing performance of different modified asphalt will also be compared. This research aims to deeply analyze the mechanism of the adhesive self-healing on the interface between asphalt and aggregate, accurately evaluate this potential, and effectively strengthen the adhesive self-healing performance. The achievements of this research will contribute to the comprehensive understanding of the intrinsic properties of asphalt and further provide the theoretical foundation and technical supports for the asphalt modification scheme and preferable material selection to finally relieve the water damage and enhance the endurance of asphalt pavement.

沥青作为胶结料具有粘附性与自愈合两个本质属性。要全面理解其基本性能，就需要将这两个属性联系起来进行研究，即粘附性自愈合。而目前的研究以引起沥青材料自身裂缝闭合的内聚性自愈合为主，对于促使沥青与集料界面再粘附的粘附性自愈合研究较少，造成了沥青粘附性研究停滞不前、自愈合研究混乱等问题。本项目在微观上采用以原子力显微镜、表面能为主的试验方法探究沥青粘附性自愈合机理，结合CT扫描等现象学手段分析细观愈合进程与演化规律，改进现有的拉拔试验与直剪试验并借助汉堡浸水车辙、疲劳小梁试验进行宏观验证，提出粘附性自愈合的评价方法，在此基础上建立表达方程、明晰影响因素、比选不同改性沥青的粘附性自愈合性能。研究旨在通过多尺度的手段对沥青与集料界面粘附性自愈合进行机理解析、准确评价与有效增强。预期成果有利于理解沥青的基本特性，为缓解路面水损害、提升路面耐久性的沥青改性方案及材料优选提供理论依据与技术支撑。

随着道路服役时长以及交通量的增长，路面损害会频繁产生。对于沥青路面来说，剥落、麻面与飞散等主要病害会降低路面结构的使用寿命，增加路面维修、养护成本。产生以上路面病害的主要原因在于老化、水损害等因素引发的路面沥青的粘附失效。研究发现，若给予一定的间歇期与合适的温度，粘附失效的沥青‒集料会重新产生粘附，表现出自愈合特性，使得已产生微裂缝或宏观破坏的沥青混合料在一定程度上愈合空隙、重新形成强度，及时避免或延迟裂纹的发展，延长材料的疲劳寿命。鉴于自愈合性能是沥青材料的固有性能之一，在对沥青路面的长期黏结性能进行评价时，将粘附与自愈合性能纳入考虑范围内能够更贴合实际路面的使用情况。探究沥青混合料自愈合的形成机理和影响因素，找到合适的方法提升沥青混合料的自愈能力，对抵抗沥青混合料的疲劳开裂，延长沥青路面的服役寿命具有至关重要的意义。.本项目在微观上采用以红外光谱实验、凝胶色谱实验及表面能实验为主的试验方法探究沥青粘附性自愈合机理，结合CT扫描等现象学手段分析细观愈合进程与演化规律。在中观层面分别利用拉拔实验及动态剪切流变实验评价了不同沥青的断裂自愈合性能及流变自愈合性能。并研究了不同因素对沥青材料自愈合性能的影响，包括愈合时间、愈合温度、沥青种类、老化、干湿条件等因素。在借助沥青混合料四点弯曲疲劳小梁试验进行宏观验证，将沥青混合料的疲劳自愈合性能与沥青的拉拔实验得到的结果进行了相关性分析。并基于UTM实验仪，改进现有的拉拔试验并开发出新的评价沥青-石料界面粘附自愈合性能的实验方案，在此基础上明晰影响因素、比选不同改性沥青的粘附性自愈合性能。总体上，本研究通过多尺度的手段对沥青与集料界面粘附性自愈合进行机理解析、准确评价与有效增强。成果有利于理解沥青的基本特性，为缓解路面水损害、提升路面耐久性的沥青改性方案及材料优选提供理论依据与技术支撑。