Evaluation of the Electromagnetic Shielding Performance of UHPFRCC before and after Cracking

In this study, the crack distribution and electromagnetic shielding characteristics of UHPFRCC before and after cracking were evaluated according to fiber combinations. After evaluating the mechanical and electrical properties of each combination, an electromagnetic shielding test of a non-cracked panel specimen was conducted. Subsequently, the panel specimen was subjected to a monotonic load or repeated load. In the case of the test specimen with a repetitive load, the crack length, crack area, and electromagnetic shielding were measured at each load stage. According to the experimental results, the incorporation of organic fiber decreased the compressive strength and density of UHPFRCC. In particular, the incorporation of carbon fibers adversely affected the tensile behavior owing to dispersibility problems. The hybrid fiber combination increased the electrical resistivity. However, the incorporation of carbon fibers improved electromagnetic shielding performance compared with the single incorporation of steel fibers. The fiber combination significantly affected the crack length and width than the crack area. In addition, as cracks occurred, the electromagnetic shielding performance of a test specimen showed an average decrease of up to 20%.