Influence of chemically treated carbon fibers on the electromagnetic shielding of ultra-high-performance fiber-reinforced concrete

• Published in: Archives of Civil and Mechanical Engineering 2020-12, Vol.20 (4), p.123, Article 123
• Main Authors: Yoo, Doo-Yeol, Kang, Min-Chang, Choi, Hong-Joon, Shin, Wonsik, Kim, Soonho
• Format: Article
• Language: English
• Subjects: Ammonia; Carbon fibers; Cement; Chemical treatment; Civil Engineering; Concrete mixing; Ductility; Effectiveness; Electrical resistivity; Electromagnetic shielding; Engineering; Fiber reinforced concretes; Graphene; Mechanical Engineering; Mechanical properties; Nitric acid; Original Article; Particle size; Physical properties; Reinforced concrete; Reinforcing steels; Silica; Sodium hydroxide; Structural Materials; Surface treatment; Tensile strength; Ultra high performance concrete
• ISSN: 1644-9665; 2083-3318; 1644-9665
• DOI: 10.1007/s43452-020-00117-y

The effects of carbon fiber and its surface treatment through chemical solutions on the mechanical properties and electromagnetic (EM) shielding of ultra-high-performance fiber-reinforced concrete (UHPFRC) were analyzed. Three types of carbon fibers chemically treated with sodium hydroxide, nitric acid, and ammonia solutions were evaluated, along with a plain carbon fiber control sample, at two different concentrations of 0.1% and 0.3% by weight. The surface of carbon fiber was oxidized by chemical solutions. The conductivity of UHPFRC increased with increasing the carbon fiber content, and slightly better conductivity was obtained using the chemically treated carbon fibers than plain fibers at the lower content of 0.1 wt%. Both steel and carbon fibers were effective at improving the shielding effectiveness of ultra-high-performance concrete, and a higher shielding effectiveness was achieved for higher carbon fiber content. Surface treatment using the nitric acid solution was the most effective at enhancing the tensile performance and EM shielding effectiveness, and the best shielding effectiveness (49.0 dB at 1 GHz) was achieved for UHPFRC with 0.1 wt% nitric acid treated carbon fibers. The shielding effectiveness was found to be generally proportional to the electrical conductivity, although its increase was minor relative to that of the conductivity. Graphic abstract