关键词: 道路材料, 自愈合, 微胶囊, 沥青再生剂, 包覆率, 延度试验

Abstract: The urea-formaldehyde resin microcapsules wrapped with asphalt regenerant for asphalt self-healing were produced by in-situ polymerization,and the core to wall mass ratio,final pH, temperature,and the concentration of the emulsifier were determined as four key factors. Orthogonal experiments of the four factors and three levels were then conducted. Analysis result showed that pH and temperature had greater influence on microcapsule preparation than the other two. The optimum conditions for preparing the microcapsules were determined as formaldehyde to urea molar ratio of 4:5,core to wall mass ratio of 6:5,final pH of 4,temperature of 70℃ and the mass percentage of dodecyl benzene sulfonic acid sodium(SDBS) of 0.5%,under which the obtained microcapsules had dense surface with an average particle size of 21.14μm and the coating rate reached 85%. Finally,the ductility tests were carried out on the intact and cracked specimen after self-healing to study the self-healing ability of common matrix asphalt and the asphalt with self-healing microcapsules. The test showed that the ductility healing rate of asphalt could increase with the dosage of microcapsule,but more microcapsule dosage did not always provide a better effect and the optimal dosage was found as 0.3% with a resulting healing rate of 38.67%.

Key words: road material, self-healing, microcapsule, asphalt regenerant, coating rate, ductility test