• Journal of the Korean Institute of Navigation
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• v.14 no.2
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• pp.33-59
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• 1990

In cold season, the developed extratropical cyclones and associated cold fronts, and NW winter monsoon are encountered very frequently in the North Pacific, especially in the northwest part of it. The two sea areas, namely, the northwest part of North Pacific, especially the eastern area far off Japan east coast, and Burmuda Triangle in the North Atlantic are generally known as two of the most dangerous areas in the world because of high incidence of sea casualties. Even large ocean going vessels were sunk frequently due to strong winds and very high seas caused by NW monsoon or developed cyclones during the winter months. The purpose of this paper is to analyse the real state of heavy weather and high sea phenomena on the vesscls at sea, thus helping mariners operate in such conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.71-72
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• 2010

The study is compared temperature history and strength of concrete followed by covering method of insulation curing of cold weather concrete with double bubble sheet. The results were as follows. First of all, in temperature history of concrete, the internal temperature of concrete fell down to $0^{\circ}C$ before/after 60 hours, having nothing to do with covering method. The study could see that, when sheet was isolated, it fell down to low temperature quickly in early curing. When the study measured compressive strength of core specimen, there were no large differences among placing methods. However, compressive strength fell down in all ages when sheet was isolated.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.618-621
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• 2006

This paper is to investigate temperature history of cold weather concrete depending on insulation curing sheet kinds. Insulating effect according to curing sheet is shown in order of 5 layer bubble sheet, combination of PE form and 3 layer bubble sheet and 3 layer bubble sheet. It maintained above $10^{\circ}C$ of minimum temperature until the completion of initial curing period when bubble curing sheet was supplied regardless of curing sheet kinds. Five layer bubble curing sheet secure higher curing temperature than any other curing sheet applied in this experiment by as much as $2{\sim}3^{\circ}C$, which performed remarkable insulation effect. Concrete applied with curing sheet secured above $65^{\circ}D{\cdot}D$ of maturity, at which concrete had 5MPa of compressive strength at 3 days.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.33-34
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• 2011

In this study, using the double bubble sheet to anti-freezing method in winter the soil embanking Mock up as a part of the development process was carried out. As results, two layers of the double bubble sheet effect 12.6℃~13.8℃ temperature difference of out door temperature that proved superior insulation and thermal performance of the double bubble sheet.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.95-100
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• 1996

This paper presents the experimental study on hardening process of high-strength and high-flowable concrete. The experiments were performed to investigate any unfavorable construction situations since the actual concrete placement has been scheduled in cold weather period, so that the high quality concrete construction is convinced to be successfully carried out. The tests were conducted using 600nm and 1000nm height of steel tube to simulate the practical concrete filled steel tube columns according to the following variables as: the categories of chemical admixtures, curing temperatures and curing schemes. The test results were analyzed in terms of hardening speed, internal heat of hydration and history of strength gain. This paper emphasizes the importance of curing schemes on durability and the use of hardening accelerators on strength gain.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.421-424
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• 2005

Discusses the results of an investigation of the relationship between maturity in field-cured specimens and that from the thinner dimension structure to thick, particularly at cold weather concrete. Tests were carried out on two different concrete mixes with 28 day compressive strengths ranging approximately 30MPa. Ready-mixed concrete was used, and test specimens were the conventional field-cured 10$\times$20cm concrete cylinder with insulating materials and without them, and test structures were the thinner(width 20cm), the general(width 40cm), the thick dimension(width 60cm), respectively. Tests were performed at age of 3, 7, 14, 28 day. Analyses of test results show that the maturity of concrete for require compressive strength was suggested to be keep higher than $164D^{circ}D$ until at least from 8day to 10day

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.29-32
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• 2006

Experimental test results of field construction, Cheongju University Educational Liberal Art Building, applying the insulating curing method on slab concrete showed that the quality of concrete in fresh and hardened state satisfied all target values. Temperature history of slab concrete in A and B area secured more than $7.8{\sim}9.2^{\circ}C$ higher than outside atmosphere. After completing certain curing period of time on the surface of the structure, crack occurrence was not found. It is concluded that the preventing vaporization of moisture by the insulating curing method reduces plastic and drying shrinkage as welt as improves durability.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.245-248
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• 2004

The prediction of the strength of cold weather concrete and the analysis of the insulating material effect were performed to apply the prediction function with maturity concept for quality control of them in this study. The several results driven from above processes were summarized as followings. First, the difference between the temperature of cylinder covered with insulating materials and that of cylinder without them was $4.5\~6.0^{\circ}C$. Second, the maturity of concrete was suggested to be keep higher than $96\~115^{\circ}C{\cdot}D$ until at least 7-day and the temperature of fresh concrete was suggested to be keep above $10^{\circ}C$ directly after set.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.273-276
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• 2004

Recently. cold weather constructions were popularized because of the importance of construction term. The special method about mix design and curing of concrete was being planned to conduct cold weather constructions, but these method were not considered in a low temperature time. A Strength revelation of concrete is delayed in a curing condition of low temperature. If a construction was loaded in this case, cracks or remaining deformations are generated in a construction. So, a strength revelation characteristic in early age was investigated to secure early strength of concrete in curing condition of a low temperature. In this study, the method about concrete mix design was presented to secure construction safety in a low temperature time.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.37-38
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• 2011

This study is to analyze and compare improved curing sheet with blue sheet in order to verify the performance related to tensile stress. As results, it is confirmed that improved curing sheet(MP+BBS1) is better than the blue sheet at using field already. Synthetically, curing sheet improved by MP is analyzed to be available instead of the original because it is superior to tensile stress.