A Fully Coupled Electromagnetic Irradiation, Heat and Mass Transfer Model of Microwave Heating on Concrete

Due to the potential for significant process benefit, microwave assisted concrete recycling is highlighted by many scholars and engineers over the world recently. In this paper, a multi-field model is established to simulate the microwave heating process of concrete specimen with single-particle aggregate by using of COMSOL Multiphysics. The validation of this model is verified by comparison with temperature from experiment. Mechanical properties of aggregate-mortar interface during microwave heating process was experimentally investigated. Electric, temperature, stress field evolution and moisture transformation during microwave heating process are discussed in detail. Temperature and stress gradient at mortar-aggregate interface influenced by microwave heating power, frequency and duration are analyzed and graphically presented, which are the dominant factors to achieve the interface debonding. Based on the comparison between concrete absorbed energy and temperature variation, energy efficiency for microwave heating concrete is also briefly discussed. Results of this investigation could provide a multi-field understanding for the microwave treatment on concrete.