Chapter 20 - Cement-based EMI shielding materials

Abstract

Cement-based materials are the most common structural materials in civil engineering. The wide application of concrete, cement mortars, and cement-based composites in structures requires new standards for cement-based materials. One of them seems to be the barrier to the transmission of electromagnetic fields—in other words, the prevention of emissions from the electronics inside the structure to the outside, while preventing them from external emissions. Electromagnetic interference (EMI) shielding is relevant to the safety of strategic structures such as electric power stations, and communication routes or underground vaults are very common nowadays with close proximity to strategic structures. Cement is marginally conducting, so the application of a cement-based matrix with a conductive filler allows composites to be electrically conductive while increasing its shielding effectiveness. That effectiveness depends on the electric conductivity and EM parameters of the barrier. A conductive filler can be a conductive polymer, carbon material (graphite or carbon fiber), or metal material in a form of powder, fiber, or plate. This chapter presents the recent insights on the cement-based EM shielding technology, with a special focus on applied fillers and their influence on shielding effectiveness.