沥青自修复微胶囊研究进展

A State-of-the-art on Microcapsules for Asphalt Self-healing

微胶囊技术在世界上已应用于多个领域,包括医药、食品和化工等,具有广阔的应用前景。将微胶囊引入到沥青材料自修复中,可提高沥青材料的自修复能力并在裂缝产生初期即可自我修复,延长路面使用寿命。与传统的裂缝修补方法相比,微胶囊自修复技术具有节能减排、降低养护成本和防止微裂缝扩展至宏观裂缝等优势。然而,沥青自修复微胶囊技术仍处于初步探索阶段,将微米级微胶囊应用于沥青材料自修复领域还存在着微胶囊强度控制范围不够明确,微胶囊破裂理论尚不成熟,且微胶囊制备工艺参数设计尚不统一等问题。因此,研究者们除研究制备工艺的影响外,还主要从选择合适的制备工艺影响参数和微胶囊的结构与性能方面不断尝试,并取得了丰硕的成果。随着制备工艺的不断成熟和影响参数的不断优化,经原位聚合法制备的微胶囊结构致密、性能优良。目前对掺微胶囊的沥青材料自修复的研究仍存在对沥青材料自修复提升效果的评价方法和评价指标尚不统一等问题。掺微胶囊的沥青材料自修复效果主要通过不同的指标来体现,包括延度、复数模量、拉伸强度、试件的载荷和沥青混合料的疲劳寿命等。其中,还对掺微胶囊的沥青混合料进行了路用性能研究。通过不同的评价指标表明,微胶囊显著提升了沥青材料的自修复效果;掺微胶囊的沥青混合料的水稳定性和高温稳定性略有下降,低温抗裂性下降较大,但仍满足规范要求。为总结沥青自修复微胶囊的研究进展,本文对比分析了多种自修复微胶囊制备方法的优势和特点,解析了影响微胶囊质量的主要因素(芯壁比、反应温度、终点pH值、乳化转速、酸化时间),总结了微胶囊的结构与性能的表征方法,介绍了掺微胶囊沥青材料自修复性能的评价方法与提升效果,阐述了微胶囊对沥青混合料路用性能的影响,探讨了借助分子动力学手段研究掺微胶囊的沥青材料自修复行为理论的可行性并展望了其未来发展前景,以期为微米级微胶囊的应用与发展提供参考。

Microcapsule technology has been applied in many fields in the world,including medicine,food and chemical industry,and has broad application prospects.Introducing the microcapsule into the self-healing of the asphalt material can improve the self-healing ability of the asphalt material,self-healing in the initial stage of the crack generation and prolong the service life of the pavement.Compared with traditional crack healing methods,microcapsule self-healing technology has the advantages of energy saving and emission reduction,reducing maintenance cost and preventing micro cracks from expanding to macro cracks.On the other hand,the self-healing microcapsule technology of asphalt is still in the preliminary exploration stage.For the application of micron-sized microcapsules in the self-healing of asphalt materials,the required compressive strength of microcapsules remains unknown,and the theory of microcapsule rupture is immature,and there is no wide consensus on the design of microcapsule preparation process parameters and the eva-luation methods of the improvement of self-healing performance of asphalt mixture containing microcapsules(AMM).Therefore,in addition to studying the influence of the preparation process,the researchers have been trying to select the appropriate preparation process to influence the parameters and the structure and performance of the microcapsules,and have achieved fruitful results.With the continuous maturity of the preparation process and the continuous optimization of the influencing parameters,the microcapsules prepared by the in-situ polymerization method have a compact structure and excellent performance.For the self-healing of AMM,there is no wide consensus on the evaluation methods of the improvement of self-healing performance of AMM.At present,the self-healing effect of AMM is mainly manifested by different indexes,including ductility,complex modulus,tensile strength,specimen load and crack opening displacement value,and fatigue life of asphalt mixture.The road performance of the AMM was also studied.Through diffe-rent evaluation indicators,it has better self-healing effect on asphalt mixture,the incorporation of microcapsules slightly decreases the moisture stability and high temperature stability of AMM,and decreases its low temperature crack resistance greatly to barely above the requirements.A comprehensive review on self-healing microcapsules for asphalt materials is conducted in this research.Specifically,the preparation methods of self-healing microcapsules and the main factors affecting the quality of microcapsules(core-wall ratio,reaction temperature,end point pH value,emulsifying speed and acidizing time)are compared and analyzed.In addition,the structural characterization methods of microcapsules are presented,the evaluation method and improved self-healing performance of AMM are introduced,and the mechanical performance of AMM are elaborated,the feasibility of studying the self-healing behavior of AMM via molecular dynamics is discussed.We have confidence that the microcapsules have a bright future in the development and provide reference for the application and development of micro-scale microcapsules.