Improving the Electromagnetic Properties of Bitumen Using SiC-Fe3O4 Composites
Xiaoming Liu, Ziqi Wei, Yu Zhao, Daxiong Yan
Abstract
It is important to further improve the microwave absorption capacity of bitumen to promote the application of microwave heating in pavement maintenance. SiC-Fe3O4 composites were prepared as microwave-enhanced materials based on the impedance matching theory and the limitation of traditional single-phase microwave absorber. A network analyzer was used to measure the electromagnetic parameters. The rheological properties were evaluated and the morphological characteristics of SiC-Fe3O4 composites were studied. The process of microwave-heating of bituminous concrete was simulated and the heating rate and heat distribution were analyzed intensively. The results showed that the reflection loss of bitumen containing SiC-Fe3O4 composites reached −21.82 dB (the microwave reflectivity was only 1%), which is 13.4 dB lower than that of the bitumen containing SiC. The average heating rate of the bituminous concrete containing optimum SiC-Fe3O4 composites was 0.322°C/s, which is 1.88 times of that of pure bituminous concrete, and higher than that of bituminous concrete containing either SiC or Fe3O4. SiC-Fe3O4 composites improved the thermal conductivity of bituminous concrete, as well. The rheological properties of bitumen did not decline. The microstructure of SiC-Fe3O4 composites contributed to microwave absorption. It can be concluded that the bitumen containing SiC-Fe3O4 composites has stronger microwave-absorption ability compared with the bitumen containing a single-phase absorber. The bituminous concrete with composites had a greater microwave heating effect, and the optimum mass ratio of SiC to Fe3O4 was 1∶2.