Enhancing electromagnetic wave absorption and flexural properties in carbon fiber-reinforced foamed cement-based composites

This work fabricated carbon fiber (CF)-reinforced foamed cement-based composites with excellent electromagnetic wave (EMW) absorption performance and flexural properties. The reinforcement effect and mechanism of different CF dosages were studied. The results show CF significantly improves the EMW absorption properties of foamed cement-based materials. The balancing of impedance matching and loss capacity by changes in CF doping is the main reason for the excellent EMW absorption properties with absorption bandwidths of 10.96 GHz (<−7 dB) and 5.20 GHz (<−10 dB). The addition of CF greatly increases the dielectric loss of the composites, especially the polarization loss. Moreover, CF improves peak strength, post-peak ductility, strength degradation, and flexural toughness of foamed cement-based composites. The the peak deflection and strength were enhanced by 142% and 144%. The fracture cracks of the reinforced specimens change to sawtooth-like and the fracture surface becomes uneven. The randomly arranged CF forms an integrated fracture-resistant network and a better energy dissipation modes, which improves the plastic deformation and dissipation capacity of the specimen. Therefore, the flexural properties of the specimen are improved.