Fatigue behavior of microcapsule-induced self-healing asphalt concrete

Asphalt has an intrinsic self-healing character. However, the rate of damage formation is much higher than the rate of damage healing. To promote the self-healing capability of asphalt materials, micro-encapsulation technique has been regarded as the potential method. To illustrate the benefits of microencapsulation on the pavement engineering, the fatigue behavior of microcapsule-induced self-healing asphalt concrete was investigated. Firstly, the melamine urea formaldehyde (MUF) microcapsules containing rejuvenator were fabricated via an in-situ polymerization method. The surface morphology, the diameter and the shell thickness of the microcapsule were observed by scanning electron microscopy. The thermogravimetric analysis was used to ensure the high temperature stability of the microcapsule. The infrared spectroscopy analysis technology was used to investigate the components of the microcapsule material. Then, a four-point bending fatigue-healing-fatigue test was designed to study the effect of the microcapsule on the fatigue life of asphalt mixture specimen. From the test results, it can be concluded that the addition of 3 wt% microcapsules can double the fatigue life of the AC-10 asphalt mixture.