Self-healing performance and prediction model of microcapsule asphalt

Asphalt is a kind of material with self-healing ability, but the rate of self-healing can not repair the damage under real load in time. Microcapsule technology is considered to be an effective technology to improve the self-healing ability of asphalt. Clarifying the self-healing behavior of microcapsule asphalt and quantitatively evaluating the improvement effect are the premise of further practical application of microcapsule technology. In this study, a fatigue-healing-fatigue test was performed using a dynamic shear rheometer. The ratio of dynamic modulus decay rate before and after asphalt healing (HI) was employed to evaluate the self-healing performance of microcapsule asphalt. In addition, the fatigue-healing-fatigue tests of microcapsule asphalt with different damage degree, microcapsule content and asphalt type were carried out under different rest time and healing temperature conditions; The test results showed that HI increased nonlinearly with the increase of rest time, healing temperature and microcapsule content, and HI decreased nonlinearly with the increase of damage degree. Then, based on the polymer self-healing theory, a macro self-healing behavior model of microcapsule asphalt considering two-stage healing process was established, which can accurately predict the macro healing ability of microcapsule asphalt. Finally, the micro mechanism of repairing asphalt microcracks by microcapsules was obversed via fluorescence microcopy.