Designing Double-Layered Cement-Based Wave-Absorbing Materials with Shaped Surfaces

Abstract

Abstract Electromagnetic wave absorbing cement-based materials can effectively prevent precision instrument errors, computer information leakage and human health issues brought about by electromagnetic pollution. A strategy was suggested to prepare cement-based absorbing materials containing convex surface and bilayer structure viva controlling the vibration time and the admixture content of polymeric bonding agent. In this way, the expanded polypropylene filling rate of the matching layer was close to 90%, which optimized the impedance matching between the specimen and the free space. With this distinctive surface and structure, excellent absorption performance and mechanical property was achieved with less doping of expanded polypropylene. For the cement-based composite containing 30 vol% expanded polypropylene, the bandwidth below -10 dB in the frequency range of 2-18 GHz was about 14 GHz, the flexural and compressive strengths was about 4.5 MPa and 30 MPa, respectively. In comparison with the samples in reported literatures, the cement-based containing shaped surface and bilayer structure showed the best electromagnetic wave absorption performance and mechanical strength.

Keywords: Keywords: Shaped surface, Double-layer structure, mechanical behavior, expanded polypropylene