Electromagnetic wave absorption properties of carbon black/cement-based composites filled with porous glass pellets

摘要

Cement-based composites filled with carbon black (CB) and porous glass pellets(GPs) were prepared, and the electromagnetic wave absorption properties (EMAPs) were investigated with the arch method in 1.7-18GHz. Results indicate that introducing of GPs into cement-based materials enhances the EMAPs significantly. The larger the particle size is, the lower the impedance of the composite is. The number of absorption peaks increases, the reflectivity curve becomes flat, and the EMAPs increase first and then decrease. The GPs with the size of 0.25-1.0mm contribute most to the EMAPs with the same content. Graded GPs produce high mechanical strength, and the synergistic effect of particles with different sizes on the enhancement of EMAPs is not obvious. The optimal content of GPs and composite thickness are 50 vol% and 20-30mm, respectively. The composite reaches the lowest average reflectivity at -9.67dB, and the bandwidth below -10dB is 7.47GHz when CB is 1.5g/L, the thickness is 20mm and the filling ratio is 50 vol%.