Review of the Applications of Microwave Heating for Asphalt Pavement Maintenance

Abstract

The propagation of microcracks into more serious pavement distresses is a major concern for asphalt pavements. Much work has been done to accelerate and control the asphalt self-healing of microcracks through the application of external heating methods including microwave heating. This thesis provides a state of the art of application of microwave heating of asphalt pavements, including self-healing. The principles of microwave heating, components of a microwave system, and different types of microwave systems are discussed. Then, an extensive literature review on the use of microwaves on asphalt pavements is presented. The review covers several applications of microwave heating on asphalt pavements and additives that enhance the microwave-absorbing capabilities of asphalt materials. Then, the results of a laboratory fatigue-heal cycle experiment are presented. The results demonstrate the ability of microwave heating to activate asphalt self-healing. Then, a 1D microwave heat transfer model is presented. A sensitivity analysis is performed on several model parameters. The analysis reveals that some parameters, such as thermal conductivity, do not significantly impact the microwave heating outcome, while some, such as applied microwave power density, do. Finally, recommendations are made for future work including field trials of discussed applications and implementation of the presented model in a computer application.