Abstract

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

中文翻译：

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化学处理碳纤维对超高性能纤维增强混凝土电磁屏蔽的影响

摘要

分析了碳纤维及其化学溶液的表面处理对超高性能纤维增强混凝土（UHPFRC）的机械性能和电磁屏蔽的影响。评价了三种用氢氧化钠，硝酸和氨溶液化学处理过的碳纤维，以及普通碳纤维对照样品的两种不同浓度，分别为0.1％和0.3％（重量）。碳纤维的表面被化学溶液氧化。UHPFRC的电导率随碳纤维含量的增加而增加，并且在0.1 wt％的较低含量下，化学处理的碳纤维比普通纤维获得的电导率略好。钢纤维和碳纤维均可有效提高超高性能混凝土的屏蔽效果，碳纤维含量越高，屏蔽效果越好。使用硝酸溶液的表面处理在增强拉伸性能和EM屏蔽效果方面最有效，对于含0.1 wt％硝酸处理的碳纤维的UHPFRC，屏蔽效果最佳（在1 GHz下为49.0 dB）。尽管屏蔽效率相对于电导率的增加很小，但发现其屏蔽效果通常与电导率成正比。1 wt％硝酸处理的碳纤维。尽管屏蔽效率相对于电导率的增加很小，但发现其屏蔽效果通常与电导率成正比。1 wt％硝酸处理的碳纤维。尽管屏蔽效率相对于电导率的增加很小，但发现其屏蔽效果通常与电导率成正比。

图形摘要