Synergistic effect of MWNT/fly ash incorporation on the EMI shielding/absorbing characteristics of cementitious materials

• Published in: Construction & building materials 2016-07, Vol.115, p.651-661
• Main Authors: Nam, I.W., Lee, H.K.
• Format: Article
• Language: English
• Subjects: Analysis; Carbon nanotubes; Cement; Cementitious material; Electromagnetism; EMI shielding/absorbing; Fly ash; Nanocomposites; Nanotubes
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2016.04.082

[Display omitted] •A specimen consisting of CNT 0.6%, SF 20%, and FA 75%, exhibited the best EMI SE.•Synergistic effect in EMI SE was attributed to CNT network and Fe2O3 in the matrix.•The computational simulation work corresponded to the experimental EMI SE results. The present study aims to develop electromagnetic interference (EMI) shielding materials of which the EM wave shielding/absorbing capabilities were enhanced by a synergistic effect of multi-wall carbon nanotube (MWNT) and fly ash (FA) in terms of EM characteristics. The MWNT/FA-added cementitious materials were fabricated with various content ratios of FA and silica fume (SF). SF was incorporated as a dispersion agent of MWNT and EMI shielding effectiveness (SE) of the cementitious materials was assessed in an effort to determine optimum content ratios of FA and SF. The best EMI SE was achieved by the specimen comprised of MWNT 0.6%, SF 20%, and FA 75% (C-FA75-SF20) as exhibiting −8.0∼−57.1dB at a frequency range from 1 to 18GHz, indicating a synergistic effect of MWNT and FA. The superior EMI SE of the C-FA75-SF20 was assessed by three different tests, i.e., SEM observation, energy-dispersive X-ray spectroscopy analysis, and electrical & electromagnetic properties evaluation. Furthermore, a computational simulation work demonstrated that the experimental EMI SE results of the C-FA75-SF20 correspond to the simulation results.