Cement composites with carbon fiber for electromagnetic interference shielding applications

This study aims at identifying a significant inflection point of electromagnetic (EM) shielding effectiveness (SE) between the length and concentration of carbon fibers in the cement composites. Samples are prepared by mixing carbon fibers featuring lengths of 159, 409, 900, 2129, 3169, and 7299 μm with cement paste, at concentrations of 1, 2, 3, 4, and 5 wt% for all the lengths. The EM shielding performance is measured using the ASTM-D4935 method. Through the linear and exponential fitting analysis, it is verified that the optimal EM shielding performance with enough fluidity of cement composites appears at a specific concentration (2 wt%) and specific length (2 mm). Therefore, when using carbon fibers to improve the electromagnetic wave shielding performance of a building, we suggest the sweet spot of its length and content. We believe that this can provide a reference point for the realization of electromagnetic wave shielding performance above a certain level.