石墨烯微胶囊沥青双机制愈合机理研究

Study on Double Healing Mechanism of Graphene Microcapsule Asphalt Binder

石墨烯微胶囊沥青是一种具有较强自愈能力的新型先进路面材料。为分析石墨烯微胶囊对沥青自愈性能的影响,采用试验与模拟相结合的手段对石墨烯微胶囊沥青的愈合机理进行了研究。首先,基于动态剪切流变仪测试了石墨烯微胶囊沥青的自愈性能;然后,借助红外光谱、荧光显微镜和分子动力学模拟分析了石墨烯微胶囊沥青的“自修复”愈合机理;最后,借助动态剪切流变仪对“自修复-热诱导”双机制下石墨烯微胶囊沥青砂浆的自愈机理进行了分析。研究结果表明:石墨烯微胶囊的加入能够显著提高沥青自愈性,掺量和间歇时间增加均能显著提升石墨烯微胶囊沥青的自愈合效果;“自修复-热诱导”双机制作用下石墨烯微胶囊沥青砂浆自愈性能明显强于“自修复”单机制作用。“自修复-热诱导”双机制愈合机理为:裂缝处石墨烯微胶囊破裂,再生剂流出填充裂缝并促进裂缝快速融合;同时,石墨烯微胶囊囊壁的石墨烯与碳纤维形成导电通路,在电流作用下产生热量,加快了沥青分子与修复剂分子的扩散速度,进一步促进了裂缝的愈合。

Graphene microcapsule asphalt binder is a new functional pavement material with an excellent self-healing ability. Experimental and simulation methods were employed to study the effects of graphene microcapsules on the self-healing properties of asphalt binders. First, the self-healing properties of graphene microcapsule asphalt binders were tested by a dynamic shear rheometer(DSR). Then, the self-healing mechanism was analyzed by infrared spectrum, fluorescence microscope, and molecular dynamic simulation. Finally, the self-healing and induction heating double-healing mechanism of graphene microcapsule asphalt mastic were studied by a DSR. The results showed that graphene microcapsules improved the self-healing properties of the asphalt binder. The effectiveness of the graphene microcapsules increased with the increase in the graphene microcapsule content and recovery time. The effect of the self-healing and induction heating double-healing mechanism was better than that of a single-healing mechanism. In the self-healing and induction heating double-healing process, the graphene microcapsule breaks at the cracks and the rejuvenator flows out to fill in the cracks. Meanwhile, the graphene and carbon fibers form a conductive path that generates heat under the action of the current. This accelerates the molecular diffusion speed of the asphalt binder and rejuvenator, and further promotes the healing of cracks.