A State-of-the-art on Microcapsules for Asphalt Self-healing
Liang He , Huduan Huang , Van den bergh Wim , Csaba Tóth , Jie Gao , Karol Kowalski , Valentin Jan
AbstractMicrocapsule 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.
|Journal series||Cailiao Daobao/Materials Review, [Cailiao Daobao/Materials Review], ISSN 1005-023X|
|Publication size in sheets||0.5|
|Keywords in English||asphalt material; self-healing; micron microcapsule; preparation and properties; molecular dynamics|
|Score||= 20.0, 23-07-2020, ArticleFromJournal|
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