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.