Microwave heating performance of ultra-thin microwave absorbing wear layer based on multi-physical field

The application of microwave heating technology in asphalt concrete pavement deicing has attracted much attention. However, the current approach often involves enhancing the entire asphalt pavement with microwave heating, leading to poor heating efficiency of the road surface. An ultra-thin microwave absorbing wear layer was prepared using silicon carbide (SiC) microwave enhanced aggregate to improve the microwave heating efficiency of road surface. The microwave heating efficiency and heating durability of ultra-thin microwave absorbing wear layer were investigated by microwave heating and deicing tests, and the optimum thickness of ultra-thin microwave absorbing wear layer was determined. The muti-physics microwave heating model established by COMSOL Multiphysics was used to analyze the influence of ultra-thin microwave absorbing wear layer on the intensity and distribution of electromagnetic field and temperature field during microwave heating. The results show that the ultra-thin microwave absorbing wear layer exhibits excellent microwave heating performance at a frequency of 2.45 GHz. The 10mm ultra-thin microwave absorbing wear layer has better microwave heating performance, and its temperature rate was 4.47 times and 1.40 times higher than that of the ordinary asphalt mixture and overall microwave-enhanced asphalt mixture. The stable microwave absorption property of SiC ensured that ultra-thin microwave absorbing wear layer had better microwave deicing durability, and the deicing time of ultra-thin microwave absorbing wear layer could still be maintained for about 45 s after repeated microwave heating. The numerical simulation results show that the strong microwave absorption capacity of the ultra-thin absorbing wear layer could partly enhance the electromagnetic field strength of the surface layer of the specimen, leading higher temperature on the surface of the specimen. The electric field intensity and magnetic field intensity inside the ultra-thin wave-absorbing wear layer increased by 50.9% and 15.7%, respectively, compared with ordinary asphalt mixture. In summary, it can be seen that the ultra-thin wave-absorbing wear layer can improve the microwave heating performance of asphalt pavement surface. © 2024, Central South University Press. All rights reserved.