• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.10a
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• pp.407-408
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• 2012

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.48-54
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• 2023

In this research, The basic physical properties and EMP shielding performance by thickness were evaluated for optimum composition of EMP shield concrete that can be applied on-site by mixing carbon-based materials with high conductivity into concrete that uses electric furnace oxidized slag (EOS). As a result of the evaluation, it was confirmed that the slump decreased as the amount of mixed carbon fib er (CF) increased, and increased when milled carb on (MCF) was mixed. As for the compressive strength, it was confirmed that EOS enhanced the strength compared to NA, and it was confirmed that the strength decreased when CF and MCF were mixed. As the thickness of the EMP shielding measurement increases, the shielding rate increases, and it was confirmed that the type of conductive material and the thickness of the test specimen have a greater influence on the shielding rate than the Amount of conductive material added. As a result of a comparative evaluation, EOS CF 0.2 is considered suitable for EMP shield concrete formulation.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.10a
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• pp.411-412
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• 2012

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.310-316
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• 2020

In this study, the stability and EMP shielding performance of metal-based industrial by-products aggregates with excellent conductivity and easy procurement to be used as concrete aggregates for EMP shielding are evaluated. The industrial by-products are electronic-arc-furnace oxidizing slag, copper smelting slag, and ferro-moldibdenum. The composition analysis of aggregates and aggregate stability are evaluated. As a result of the experiment, ferro-moldibdenum is shown to have l ow stability as an aggregate due to its high Free-CaO. The remaining aggregates are evaluated to be safe to use as aggregates for concrete. In addition, industrial by-products aggreagate-specimens excluding ferro-moldibdenum are shown higher compressive strength than the plain specimen. The recycle aggregates, electronic-arc-furnace oxidizing slag and copper smelting slag, are shown excellent EMP shielding performance, the EMP shielding performance is expected to increase if the average particle diameter of the aggregate is small or evenly distributed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.20-21
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• 2016

In this study, the shielding properties of concrete with conductive materials as shielding material for electromagne- tic pulse(EMP) within 10kHz~18GHz were investigated. The shielding effectiveness of specimens were compared with different entrained materials. The shielding effectiveness were determined according to MIL-STD-188-125-1, IEEE-STD-299 at 28 days of concrete curing. The results of shielding effectiveness did not meet the criteria(80dB) severely.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.2
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• pp.151-161
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• 2019

In this study, to evaluate the High Altitude Electromagnetic Pulse(HEMP) protection performance of UHPC/CNT composites by the content of Carbon nanotubes(CNTs), Electromagnetic Shielding Effectiveness(SE) test was performed based on MIL-STD-188-125-1. And the results were verified by applying the Antenna theory. In the case of UHPC with a thickness of 200 mm mixed with 1 % CNT of cement weight, the SE was 28.98 dB at 10 kHz and 45.94 dB at 1 GHz. Then the Scabbing limit thickness for bullet proof was computed based on the result of compressive strength test which was 170 MPa, and it was examined whether it satisfied the HEMP protection criteria. As a result, the required HEMP shielding criteria were satisfied in all frequency ranges as well as the scabbing limit thickness was reduced by up to 43 % compared with that of ordinary concrete.

• Magazine of the Korea Concrete Institute
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• v.20 no.6
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• pp.28-35
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• 2008

The Burj Dubai Project will be the tallest structure ever built by man; when completed the tower will be more than 700 meter tall and more than 160 floors. While the early integration of aerodynamic shaping and wind engineering considerations played a major role in the architectural massing and design of this multi-use/residential tower, where mitigating and taming the dynamic wind effects was one of the most important design criteria, the material selection for the structural systems of the tower was also a major consideration and required detailed evaluation of the material technologies and skilled labor available in the market at the time Concrete was selected for its strength, stiffness, damping, redundancy, moldability, free fireproofing, speed of construction, and cost effectiveness. In addition, the design challenges of using concrete for the design of the structural system components will be addressed. The focus on this paper will also be on the early planning of the concrete works of the Burj Dubai Project.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.477-484
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• 2019

The purpose of this study is to present basic data for developing concrete with EMP shielding as the structure materials when constructing an EMP shielded building structure. In order to use metal-based recycled aggregates with excellent conductivity and easy procurement for EMP shielding concrete, an evaluation of the stability evaluation and EMP shielding performance was performed. Through the stability evaluation, it was found that the coarse aggregate stability criterion was satisfied, but the oxidized slag did not satisfy the fine aggregate stability criterion, the oxidized slag is not satisfied. In addition, as a result of fresh concrete, the workability is increased and the air volume is decreased. The compressive strength is increased due to the high density and coarse granularity of the recycled aggregates, which increased the cement paste and adhesion, thereby increasing the compressive strength. The results of an EMP shielding test show that aggregates with high shielding performance are electronic arc furnace(EAF) Oxidizing Slag and Cooper Slag. The shielding performance is expected to increase if the average particle size of aggregate is small or uniformly distributed.

• Magazine of the Korea Concrete Institute
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• v.13 no.5
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• pp.77-81
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• 2001

부식 열화는 교량 기술자들에게 있어서 지속적인 도전을 요구하는 문제가 되어왔는데, 스텔스 항공기를 개발하게 한 새로운 재료 기술은 교량의 부식을 해결할 수 있게 하였다. 즉, 경량의 고강도 재료로 높은 피로 저항성을 갖고 있고, 부식에 강한 복합체는 교량의 재료로서 아주 바람직한 성질을 갖고 있다 섬유 보강 폴리머(FRP) 복합재료를 교량의 건설에 이용하려는 프로젝트는 1998년 현재 80 여 개가 넘게 진행되고 있는데, 이 중 미국 내에서 31개의 프로젝트가 수행되고 있다. 이 글은 미국 내에서 FRP복합체를 교량 공학 분야에 적용하려는 초기의 성공적인 시도들에 관한 내용으로 복합체의 장점, 특성, 교량 적용시 고려 사항, 그리고 향후 복합재료에 관한 기술을 토목 구조물에 적용하는데 필요한 소요 기술 등에 관하여 정리한 것이다. 이 새로운 재료는 신설 구조물의 건설과 기존 교량의 보수 및 보강에 모두 적용할 수 있으며, FRP복합체 기술을 토목 구조물과 기반 시설물 건설 분야에 적용하는 것은 지금까지 성공적인 결과를 보여 주고 있다 미국연방도로국(FHWA, Federal Highway Administration)은 이 기술을 미국 내 교통 기반 시설물인 신규 교량의 건설은 물론 기즌 교량의 보수 및 보강에 활용하는 방안에 대하여 관심을 갖고 있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.136-144
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• 2010

The bar-shaped electrode is very popular for earth construction in Korea. Copper ground rod, Deep-buried ground rod and conductive concrete ground rod are major types of the bar-shaped electrode and generally applied on the distribution system. But in most case, to obtain the targeted ground resistance is difficult, because ground resistance is very different by soil condition. Therefore, a chemicals for reducing ground resistance is applied. In this paper, the initial and the variation of ground resistance according to the applied methods and types of chemicals over one year are compared with copper ground rod applied with water and the experimental results show that the new methods with chemicals reduced not only the initial ground resistance but also the variation of ground resistance over year.