Investigation of microwave healing performance of electrically conductive carbon fiber modified asphalt mixture beams

© 2016 Elsevier Ltd This presented paper aimed to investigate the physical properties and microwave-healing performance of carbon fiber modified asphalt mixture. Two types of carbon fibers, HexTow® IM8 and AS4 (from HEXCEL Company), were added to asphalt mixture. About 2% and 4% HexTow® IM8 fiber (by mixture weight) were chopped and dry-mixed for the modified asphalt mixture. About 1.5% and 3% of HexTow® AS4 fiber (by binder weight) were pre-cut and wet-mixed with asphalt binder then the modified asphalt mixture was produced. The thermal conductivity of carbon fiber modified asphalt mixture samples increased while the electrical resistivity decreased with added fiber content. The measured original fracture strengths from elastic-supported beam bending tests indicated that the original fracture strength of the small-amount carbon fiber modified asphalt mixture maintained or decreased. However, when the content of carbon fiber exceeds a certain amount, the original fracture strength increases due to fiber reinforcement. In addition, the cyclic fracture-microwave healing tests were conducted to evaluate the healing performance of the control and carbon fibers modified asphalt mixture samples. The test results of recovered strength indicated that the carbon fiber modified asphalt mixture can achieve superior healing performance with microwave healing approach