• Journal of the Korea Concrete Institute
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• v.22 no.2
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• pp.255-262
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• 2010

The purpose of this study is to provide preliminary data on chloride diffusion of lightweight aggregate concrete containing crushed stone-powder. Accordingly, the study performed experiments using concrete aggregates of Crushed Aggregate (CG), Single-sized Lightweight Aggregate (SLG), Continuous Graded Lightweight Aggregate (CLG), and using water-binder ratio of 0.4, 0.5, 0.6, and using binder of FA and BFS. The chloride diffusion coefficient is calculated according to the NT BUILD 492. Diffusion coefficient of SLG and CLG were higher than that of CG concrete, but the difference was not significant. Also, chloride diffusion coefficient data indicated that it was highly affected by water-binder ratio, and it decreased with the decrease in waterbinder ratio. The admixture substitution of FA15% was effective in decreasing the diffusion coefficient only with water-binder ratio of 0.4 while admixture substitution of FA10+BFS20% was effective with all levels of water-binder ratio. The result of study shows lightweight aggregate concrete containing crushed stone-powder has slightly higher chloride diffusion coefficient than CG concrete, but the difference is not significant such that it can be overcome by adjusting water-binder ratio and admixture substitution. In addition, the data indicate the chloride diffusion coefficient of lightweight aggregate concrete can be estimated from the strength of lightweight aggregate.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.54-61
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• 2023

In this paper, the compressive strength, pore characteristics, and chloride diffusion coefficient were measured at 28 days of age in order to examine the influence of curing conditions for the chloride diffusion and pores in concrete cured under extreme condition. According to the test results, the compressive strength was improved as the relative humidity increased. Additionally, higher compressive strength was observed when the specimens were cured at 35℃. However, the compressive strength of specimens cured at 45℃ was decreased. Meanwhile, the chloride diffusion coefficient decreased with an increase in curing temperature and relative humidity, indicating a difference compared to the trend observed for compressive strength. On the other hand, the excellent correlation showed between compressive strength and chloride diffusion coefficient, porosity and chloride diffusion coefficient when the concrete cured under water. However, when the concrete cured under extreme condition, this correlation was significantly reduced compared to the water curing case. In contrast, it has been determined that there is no significant correlation between the average pore size and chloride diffusion coefficient, regardless of the curing conditions.

• Journal of the Korean Chemical Society
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• v.17 no.1
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• pp.31-39
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• 1973

The present paper represents a summary of the reactions of $AlCl_3$with fluorochlorocyclobutenes involving fluorine replacement, and intermolecular transfer.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.05a
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• pp.99-100
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• 2004

PCBs를 분석한 결과 붕어는 4개 지점에서 모두 검출되었으며 5.6염화 PCBs가 대부분을 차지하였고, 황소개구리는 2개 지점에서 5~7염화 PCBs가 일부 검출되었으며 나머지 시료에서는 검출되지 않았다.

• 월간산업보건
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• s.257
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• pp.13-16
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• 2009

펜타클로로나프탈렌(Pentachloronaphthalene)의 직업적 노출기준은 0.5 $mg/m^3$으로 권고하였으며 이 수준은 염화물 형태의 간 손상과 피부염의 가능성을 최소화하기 위한 것이다. 피부 흡수 경고는 동물실험에서 pentachloronaphthalene이 피부접촉 시 흡수가 용이하다는 자료를 근거로 권고하였다. 두 종류 이상의 염화나프탈렌에 노출되는 경우는 상가작용을 적용하여야 하며 감작제, 발암성, TLV-STEL에 대한 권고는 충분한 자료가 확보되지 않아 아직은 설정하지 않고 있다.

• 월간산업보건
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• s.280
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• pp.27-31
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• 2011

Vinyl chloride(염화비닐)에 대한 직업적 노출기준인 TLV-TWA를 1 ppm (2. 6 mg/$m^3$)으로 권고한 것은 간암의 가능성과 특히 간혈관육종을 최소화하기 위한 것이다. 염화비닐과 간암에 대한 명확한 사람들의 사례와 역학조사 결과를 근거로 사람에서의 확실한 발암성물질인 Al으로 분류하였다. 피부 (Skin), 감작제(SEN)의 경고주석과 TLV-STEL.을 권고하기에는 자료가 불충분하다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.132-132
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• 2008

실험실적 도금 simulator 에서 도금실험을 행하여 전기아연도금재 표면품질이 염화암모늄 및 유기첨가제 농도와 상관성을 관찰하였다. 이들은 각각 도금층의 우선배향면인 basal plane 와 연관성이 있었으며 basal plane 이 적을수록 표면 백색 및 광택이 감소하였다.

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.308-313
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• 2014

Recently, for longevity of resident building, the main trend is that the change of the inside space organization of resident building from wall construction to rhamen construction, which resulted in increase in use of lightweight composite panel. Thus, in this study, authors analyzed the engineering property of oxide of magnesium depending on the magnesium chloride addition ratio. The results of this research is expected to contribute on providing a fundamental material for the surface materials of lightweight composite panel. As the result of the experiment, as fluidity increased, air content decreased and initial set and final set as the magnesium chloride addition ratio increase. In the aspect of flexural strength and compressive strength, the test specimen showed the highest strength at 40% of the magnesium chloride addition ratio. At 20% of the magnesium chloride addition ratio, the test specimen showed the lowest water absorption rate. As the magnesium chloride addition ratio increases, the expansibility tends to increase as well in the aspect of shrinkage strain. After observing microstructure, we can see hydration products in the form of needle. It appeared high flexural strength because the hydration products have mineral fibrous tissue shape, which also contribute to the cause of the expansibility.

• Journal of the Korea Concrete Institute
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• v.26 no.1
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• pp.71-78
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• 2014

The long term integrity of concrete cask is very important for spent nuclear fuel dry storage system. However, there are serious concerns about early deterioration of concrete cask from creaking and corrosion of reinforcing steel by chloride ion because the cask is usually located in seaside, expecially by combined deterioration such as chloride ion and heat, carbonation. This study is to investigate the relation between temperature and chloride ion diffusion of concrete. Immersion tests using 3.5% NaCl solution that were controlled in four level of temperature, i.e. 20, 40, 65, and $90^{\circ}C$, were conducted for four months. The chloride ion diffusion coefficient of concrete was predicted based on the results of profiles of Cl- ion concentration with the depth direction of concrete specimens using the method of potentiometric titration by $AgNO_3$. Test results indicate that the diffusion coefficient of chloride ion increases remarkably with increasing temperature, and there was a linear relation between the natural logarithm values of the diffusion coefficients and the reciprocal of the temperature from the Arrhenius plots. Activation energy of concrete in this study was about 46.6 (W/C = 40%), 41.7 (W/C = 50%), 30.7 (W/C = 60%) kJ/mol under a temperature of up to $90^{\circ}C$, and concrete with lower water-cement ratio has a tendency towards having higher temperature dependency.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.36-42
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• 2018

GGBFS(Ground Granulated Blast Furnace Slag)-replacement is very effective for improving resistance to chloride attack and this can induce a long service life for RC(Reinforced Concrete) structures exposed to chlorides. In the work, the design parameters such as cover depth, surface chloride content, critical chloride content, and replacement ratio of GGBFS are considered, and optimum replacement ratio of GGBFS are derived with intended service life. The changes of surface chloride content and cover depth show 3.16~3.38 and 3.02~3.34 times of service life variation, which are most influencing parameters. Critical chloride content shows 1.53~1.57 times of service life variation regardless of w/b(Water to Binder) ratios. In the case of surface chloride content $18.0kg/m^3$, the most severe condition, cover depth over 70 mm and GGBFS replacement ratio over 42% are required with concrete containing w/b ratio under 0.42 for 100 years of intended service life. The condition of $13.0kg/m^3$, GGBFS replacement over 35% is required. For reasonable durability design, quantitative exterior condition and critical chloride content should be determined, and the criteria in Domestic Specification is evaluated to be conservative.