Effect of Graphite on the Microwave Susceptibility of Cement Foam Concrete

The reduction of the dielectric constant of materials is in favor of the improvement of the microwave susceptibility. A great amount of micro-pores in the cement paste introduced by a foaming agent could reduce the dielectric constant of a cement matrix, as well as reducing its apparent density. The microwave susceptibility of cement foam concrete was determined by the arch reflection method in the range of 8–18 GHz. Effect of graphite content, porosity, surface roughness, moisture content and age over the microwave susceptibility was studied. Results showed that this capacity was enhanced with the increase of graphite content, being the optimal 15 wt.%. Porosity and open porosity also help matching impedance on the surface of sample. The increase of the moisture content resulted in the fluctuation of the microwave susceptibility of concrete, while the age had no significant effect.