Microwave Crack-Healing Capability on Asphalt Mixtures with Silicon Carbide

Abstract

The application of microwave radiation is an effective technique to promote the crack-healing of asphalt mixtures. The heat increases the bitumen temperature and reduces bitumen viscosity, flowing and sealing the open cracks. Normally, these types of asphalt mixtures contain metal additives that promote microwave heating. However, the literature reports different materials heat efficiently with microwave radiation. Silicon Carbide (SiC) is a semiconductor ceramic and low-cost material, like an aggregate, with good dielectric properties that efficiently absorb microwave radiation and release the absorbed energy in the form of heat. This article reports the study of the efficacy of SiC as a potential additive for asphalt mixtures to promote asphalt crack-healing. Asphalt mixtures with constant SiC content and SiC uniform particle size of #12 (1.68 mm), #120 (0.125 mm), and #1200 (0.038 mm) were prepared. For the measurement of the crack-healing, the authors conducted three-point bending tests on semi-circular samples. Results showed that some mixtures increased the healing with the number of healing cycles; which is the opposite trend of results reported in the literature. Additionally, the healing of asphalt mixtures with #12 and #120 was higher than for #1200 SiC mixtures. Overall, the study indicates that asphalt mixtures with SiC can be crack-healed by microwave radiation.