Electromagnetic wave absorbing properties of multi-walled carbon nanotube/cement composites

The electromagnetic wave absorbing properties of multi-walled carbon nanotube (MWCNT)/cement composites were studied. The influence of the MWCNT content and sample thickness on the electromagnetic wave reflectivity was discussed and analyzed in the frequency ranges of 2–8 GHz and 8–18 GHz. When the MWCNT content is 0.6 wt.%, the cement mortar sample with a thickness of 25 mm can remarkably absorb electromagnetic waves close to the absorbing peaks in the frequency range of 2–8 GHz. The strongest peak with a reflectivity of −28 dB is obtained at 2.9 GHz. The cement mortar sample with a thickness of 35 mm presents beneficial broadband wave absorption performance between 8 and 18 GHz. The addition of 0.9 wt.% MWCNTs can notably enhance the wave absorption performance of the cement mortar and make the bandwidth below −10 dB reach 7.1 GHz in the frequency range of 8–18 GHz.