Synthesis and properties of microwave and crack responsive fibers encapsulating rejuvenator for bitumen self-healing

At present, there are mainly two ways to accelerate the self-healing of bitumen materials, namely electromagnetic induction heating or microwave heating, and capsules encapsulating rejuvenator. In this paper, a kind of multi-responsive composite fiber (MRF) was synthesized, which combined the advantages of the two ways. Scanning electron microscope (SEM), energy dispersion spectrum (EDS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and thermogravimetric analysis (TGA) tests were conducted and confirmed the successfully synthesis of MRF. Graphene oxide (GO) was evenly distributed in the fiber wall. Rejuvenator was encapsulated in MRF in the form of droplets. In addition, MRF met temperature requirement when mixed with bitumen. Microwave response behavior of MRF was studied and shown that MRF had excellent microwave heating effect. The temperature of bitumen containing MRF had a significant increase under the induction of microwave. Meanwhile, bitumen containing MRF could generate a large amount of energy under the action of microwave, which provides a basis for accelerating the self-healing of bitumen by microwave heating. Crack response behavior of bitumen containing MRF was monitored and revealed that rejuvenator that was encapsulated in MRF could flow out and accelerate self-healing of bitumen under the induction of cracks. Modified ductility test was conducted and shown that the self-healing ability of bitumen containing MRF was significantly improved under the synergistic action of rejuvenator and microwave heating. This work provides a new direction for the research of self-healing of bitumen materials.