Analysis of Electromagnetic Shielding Properties of Cement-Based Composites with Biochar and PVC as Fillers

Biochar (bio-charcoal) is a low-cost and eco-friendly material. It can be obtained by thermochemical conversion of different biomass sources, for example, in the total absence of oxygen (pyrolysis) or in oxygen-limited atmosphere (gasification). The porous carbonaceous structure of biochar, resulting from the thermal treatment, can be exploited in cement-based composite production. By introducing biochar powder or other fillers in the cement paste, it is possible to enhance the shielding properties of the cement paste. The environmental impact of polyvinyl chloride (PVC) can be reduced by reusing it as a filler in cement-based composites. In this work, cement-based composites filled with different percentages of biochar and PVC are fabricated. The scattering parameters of samples with 4mm thickness are measured by mean of a rectangular waveguide in the C-band. The shielding effectiveness of reference samples without any filler and samples with biochar and PVC is analyzed. A combination of 10 wt.% biochar and 6 wt.% PVC provides the best shielding performance (around 16 dB).