Conductive Concrete for Electromagnetic Shielding Applications

Conventional concrete is a dielectric whose properties change based on the constituents of the mixture. Consequently, it is not an effective electromagnetic shield since radio frequency (RF) waves can still propagate through it with relatively low attenuation. Recently, conductive concrete, which is a cement-based mix, was developed to achieve high electrical conductivity and high mechanical strength. Petroleum coke with different particle sizes, synthetic graphite, and steel fibers were used to improve the electrical properties of the concrete. In this paper, the effectiveness of conductive concrete as an electromagnetic shield is investigated. Steel fiber configuration and sample thickness were the parameters used in the evaluation. Frequencies between 0.3 to 11 GHz were considered in the investigation. The free space measurement method was used to measure the electromagnetic shielding effectiveness and the results showed that attenuation up to 50 dB could be achieved for the frequency range considered in the investigation.