• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.95-98
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• 1999

Recently, the use of the underwater concrete constructions with the antiwashout underwater concrete is increasing. In this study, we investigate the properties of pH, suspended solids, slump flow, box test, air contents of fresh antiwashout underwater concrete and the Unit weight, compressive strength of hardened antiwashout underwater concrete which Ground Granulated Blast Furnace Slag contents 0%, 10%, 20%, 30%, 50%, 60% at 7days and 28days age which is produced and cured in the water and sea water. As a result, Ground Granulated Blast Furnace Slag contents 30% was excellent.

• 한국안전학회지
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• 제30권4호
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• pp.142-150
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• 2015

A portable recoilless guided missile generates a strong back blast and impulsive noise at the nozzle when it launches. In the case of indoor operations, the hazard of the blast noise from a recoilless weapon increases due to limited indoor spaces. Also, the noise levels determine the operational feasibility of a weapon; therefore, it is important to predict the blast noise levels distribution in the indoor space in advance. In addition, computational fluid dynamics (CFD) method generally used for fluid related simulations, requires high computing cost and time to simulate the whole domains. The domain includes both blast wave region and large and various indoor space region. Therefore, an efficient method for predicting the far-field noise level within a short time should be developed. This paper describes an analysis model for predicting the indoor noise distributions by considering the shape effect of the building within a short time. A new developed blast wave model was implemented using the noise source. Additionally, noise reflections at the closed surfaces such as walls and noise transmissions at the opened surfaces such as windows and doors were considered in calculating the noise levels. The predicted noise levels were compared with the experimental data obtained from the indoor launch test to validate the reliability of program.

• Computers and Concrete
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• 제17권2호
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• pp.201-214
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• 2016

The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridianally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.

• 농업과학연구
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• 제4권2호
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• pp.199-214
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• 1977

본(本) 시험(試驗)은 우리나라의 각지방(各地方)에서 밭못자리 검정(檢定)에 의(依)한 수도(水稻) 품종(品種)의 도열병(稻熱病) 발생(發生) 양상(樣相)을 비교(比較) 검토(檢討)하여 저항성(抵抗性) 품종육성(品種育成)을 위(爲)한 기초(基礎) 자료(資料)를 얻고자 도열병(稻熱病) 판별품종(判別品種) 및 주요품종(主要品種) 129개(個)와 잡종계통(雜種系統) 30조합(組合)을 수원등(水原等) 6개(個) 지역(地域)에서 1976~'77년(年)에 걸쳐 실시(實施)한 바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 3종(種)의 도열병(稻熱病) 판별품종(判別品種) Set를 사용(使用)하여 6개(個) 지역(地域)의 우점(優占) race의 차이(差異)를 조사(調査)한 결과(結果) 지역간(地域間) 우점(優占) race의 차이(差異)는 인정(認定)되었으나 정확(正確)한 지대(地帶) 구분(區分)은 할 수 없었다. 2. 일본형(日本型) 품종(品種)과 Indica${\times}$Japonica육성품종(育成品種)은 저항성반응(抵抗性反應)의 지역간(地域間) 차이(差異)가 서로 다르게 나타났다. 3. 수원(水原)과 임실(任實)에서 잡종계통(雜種系統)들의 도열병(稻熱病) 저항성반응(抵抗性反應)도 서로 달랐다. 4. 도열병(稻熱病) 밭못자리 검정(檢定)에서 조사(調査) 시기별(時期別) 저항성반응(抵抗性反應)의 진전(進展)에 의(依)하여 3종(種)의 품종군(品種群)으로 분류(分類)할 수 있었다. 5. 엽도열병(葉稻熱病)에 고도(高度)의 저항성(抵抗性) 반응(反應)을 보인 품종(品種)은 일반적(一般的)으로 수수도열병(穗首稻熱病)이 거의 발생(發生)하지 않았으나 예외(例外)도 있었다.

• 한국농공학회논문집
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• 제55권4호
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• pp.65-72
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• 2013

The physical, mechanical, water purification and temperature properties of fiber reinforced porous hwang-toh green roof concrete have been evaluated in this study. The effect of the depending on replacement ratio of blast furnace slag to cement was investigated such that the replacement ratio is varied to 0 % and 30 %. Also, the replacement ratios of hwang-toh were 0, 20 and 30 %. The polyvinyl alcohol fiber was used for the reinforcing fiber. A series of pH test, unit weight, void ratio, compressive strength, after purification and variation of temperature test have been performed to evaluate the performance, water purification effect and temperature properties of the fiber reinforced porous hwang-toh green roof concrete. The test results indicate that the physical and mechanical properties of fiber reinforced porous hwang-toh green roof concrete is affected by the replacement ratio of the blast furnace slag and hwang-toh contents. Results of purifying water showed that the water purification effect of porous hwang-toh green roof concrete is about 40 %. Also, the temperature properties test results indicate the green roof blocks using fiber reinforced porous hwang-toh green roof concrete have insulation and temperature reduction effect.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.569-572
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• 2006

This study was performed to investigate the characteristics of carbonation for latex modified concrete with fly ash and blast furnace slag. The experimental variables consisted of ground granulated blast-furnace slag contents (0%, 30%, 50%), fly ash contents (0, 30%) latex contents (0, 5, 10, 15%). Two different methods of carbonation test such as $CO_2$ gas and 5% sulphuric acid digestion resistance test were varied in this study.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.239-240
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• 2009

콘크리트 판넬 부재의 폭발실험을 통해 콘크리트 구조물의 폭발에 대한 저항 성능을 정량적으로 평가하였다. 본 실험에서는 콘크리트의 강도, 보강재료를 변수로 총 8 가지 종류의 시편에 대하여 폭발실험을 수행하였다.

• Journal of Welding and Joining
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• 제20권4호
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• pp.551-556
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• 2002

Solid particle erosion wear characteristics of high Cr white iron hardfacing were investigated using the erosion wear test method according with the ASTM G76-95. Wear experiments, where the blast angle, blast distance and blast pressure were selected as test variables, were planned and analyzed by response surface method (RSM to evaluate the wear loss statistically and quantitatively. The measured wear losses well coincided with the calculated ones by the experimental equation. The wear loss of high Cr cast iron hardfacing was increased with blasting pressure, but affected in a complicated way by the blasting angle and distance. Erosion wear of high Cr cast iron hardfacing could be well predicted by RSM analysis of wear variables.

• Geomechanics and Engineering
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• 제19권4호
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• pp.361-368
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• 2019

This study aims to evaluate the applicability of a grout material that is mixed with carbon fiber, biogrout, ground granulated blast furnace slag (GGBS) powder and cement. Uniaxial compressive strength tests were performed on homo-gel samples at days of 1, 3, 7, 14 and 28. In addition, the variation of permeability with the mixing ratios was measured. Based on the uniaxial compressive strength test, it was confirmed that the uniaxial compressive strength increased by 1.2times when carbon fiber increased by 1%. In addition, as a result of the permeability test, it was found that when the GGBS increased by 20%, the permeability coefficient decreased by about 1.5times. Therefore, the developed grout material can be used as a cutoff grouting material in the field due to its strength and cut-off effect.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.463-470
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• 2000

In tunnel excavation by blast beneath the surface structures in urban area, the characteristics of ground vibration induced by blast and its influence on surface structures are analyzed by the field test and the numerical analysis on dynamic behaviors of the structure. According to the field test on the propagating characteristics of blast vibration through the rock mass and the concrete foundation pile. the attenuation index of peak particle velocity with distance shows the range of 1.7∼2.0 for the rock mass and the range of 2.0∼2.3 for the concrete pile. This shows that the blast vibration reduces more rapidly in the concrete pile. It is known from the numerical analysis on dynamic behavior of the structure that the coefficient of response, velocity ratio of structure response to input wave, is different according to the story of the structure. It can be said from this research that the characteristics of the ground vibration and the dynamic behavior of the structure should be well evaluated and be considered as important factors for safe blasting design especially in underground excavation at shallow depth in urban area.