Evaluation of Self-Healing Performance of Asphalt Concrete for Low-Temperature Fracture Using Semicircular Bending Test

Abstract

This study aims to evaluate fracture resistance and self-healing performance of asphalt concrete at low temperatures using a semicircular bending (SCB) test. Three asphalt mixtures with different types of asphalt binder were used. The applied load and crack opening tip displacement (CTOD) were measured to calculate fracture energy and the critical release rate of fracture energy (J-integral). The self-healing indexes (HIs) were defined as the ratios of fracture energy, peak load, and J-integral obtained before and after healing, respectively. The self-healing performance of asphalt mixture was investigated considering different healing temperatures, healing time, and initial crack lengths (notch depths). The results showed that the styrene-butadiene-styrene (SBS) modified asphalt mixture possessed the highest fracture resistance, as compared to the asphalt mixture modified by rubber compound and the asphalt mixture with conventional 7# asphalt binder. The self-healing ability of the asphalt mixture increased with the increase of healing temperature and healing time; while it decreased with the increase of notch length. The optimum healing temperature was determined to be 6°C at the same healing time of 8 h, whereas the optimum healing time was found to be complicated depending on mixture type. Each asphalt mixture exhibited different healing abilities, depending on healing temperature, healing time, and the performance indicator of healing index.