Deicing Properties of Magnetite Concrete Driven by Microwave Thermal Effect Characteristics

To improve the microwave deicing efficiency of concrete, magnetite as an absorbing material was used to prepare magnetite concrete (MC). Its mechanical properties and durability were studied. Furthermore, its microwave thermal effect ability (MTEA) was systematically investigated, including microwave absorption, heating efficiency, and thermal transfer properties. Based on this, the changes in deicing properties of MC under different influencing factors was systematically studied, and its applicability was verified through field deicing operation. The study results show that magnetite significantly improved the mechanical properties and freezing resistance of concrete by refining the pore structure and reducing the porosity. Compared with the control group (CG), the flexural and compressive strength of concrete with 100% magnetite content (MC4) were increased by 21.05% and 14.57%, and the frost resistance index was increased by 19.16%. Moreover, the MC4 showed superior MTEA, with microwave absorption, heating, and thermal transfer efficiency reaching 1.34, 3.07, and 4.89 times that of the CG, respectively. During microwave deicing, the icing temperature and magnetite content significantly affected the deicing efficiency of concrete. When the icing temperature was −5°C and −30°C, the deicing efficiency of MC4 was 2.15 and 2.26 times higher than that of the CG, respectively. In addition, the microwave heating effect of MC4 pavement could reach 2.70 times that of ordinary concrete pavement, and its surface ice layer could completely melt within 60 s of heating.