• 대기
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• 제30권2호
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• pp.183-193
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• 2020

In this study, Yeongdong cold air damming (YCAD) cases that occur in winters have been selected using automatic weather station data of the Yeongdong region of Korea. The vertical and horizontal scales of YCAD were analyzed using rawinsonde and numerical weather model. YCAD occurred in two typical synoptic patterns such that low pressure and trough systems crossing and passing over Korea (low crossing type: LC and low passing type: LP). When the Siberian high does not expand enough to the Korean peninsula, low pressure and trough systems are likely to move over Korea. Eventually this could lead to surface temperature (3.1℃) higher during YCAD than the average in the winter season (1.6℃). The surface temperature during YCAD, however, was decrease by 1.3℃. The cold air layer was elevated around 120 m~450 m for LP-type. For LC-type, the cold layer were found at less than approximately 400 m and over 1,000 m, which could be thought of combined phenomena with synoptic and local weather forcing. The cross-sectional analysis results indicate the accumulation of cold air on the east mountain slope. Additionally, the north or northeasterly winds turned to the northwesterly wind near the coast in all cases. The horizontal wind turning point of LC-type was farther from the top of the mountain (52.2 km~71.5 km) than that of LP-type (20.0 km~43.0 km).

• 한국건축시공학회지
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• 제13권1호
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• pp.38-47
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• 2013

When building with concrete in cold weather, an insulation method of heat curing must be determined, and a holistic curing plan that considers the characteristics of structures, the heat loss coefficient of a curing sheet, the joint condition of the curing materials and the quantity of heat produced by a heating apparatus is an essential prerequisite for protection against early frost damage. But on a number of national construction sites, there have been serious problems in cold weather concreting due to the unreliability of the information obtained from practical experience. In the construction field in Japan, there is a specification for heat curing prepared by Japanese Architectural Society, which provides an equation for calculating heat quantity. It is also necessary to adopt a detailed specification for a standard heat curing method that is applicable to all national construction sites. In this study, the effect of bubble sheets on the economic feasibility of cold weather concrete is investigated through a comparison with the blue sheets commonly prescribed in national construction sites. In conclusion, this study found that bubble sheets had the effect of reducing the cost of curing materials and the fuel cost consumed by a heating apparatus, compared to the use of blue sheets.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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• pp.313-318
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• 1998

Generally, the concrete constructed during cold weather has the frozen damage which cause the fatal damage so that heat curing and sheet curing was performed to prevent the early freezing of concrete. However, partial refrigeration caused by thermal gradient has many troubles so that the construction hasn`t been done as possible. This paper presents the development of strenth properties and optimal mix design against frozen damage under the cold weather, 1$0^{\circ}C$ below the zero.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.171-175
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• 2001

The quality control application of concrete are one of the most important problems to be considered in cold weather concreting. And, the construction is going on now Therefor, the major test variables are compressive strength of concrete, curing method and volume of air content. This shown to be possible to construction and quality control of cold weather concreting in field.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.25-26
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• 2022

The purpose of this study is to prevent serious disasters in cold weather by presenting an optimal blending design for securing high early strength when placing concrete by analyzing the properties and compressive strength of concrete formulations using high early strength admixture materials.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.953-958
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• 2001

The concrete which has placed under cold weather has some defects such as the decrease of initial strength by hydration delay, strength unrecover at unhardened concrete freezing and structural failure and crack by expansion pressure. So, in this study, we tried to develope the concrete which can be made under cold weather without defect by using of do-icing agency In concrete test, the used do-icing agency has the characteristics of de-icing and rapid hydration. By test results, Co{$NH_{2}$$]_{2}$is unsuitable for workability, and NaN$O_{2}$ is the most suitable agency for cold weather. And for curing, the cured concrete at $21^{\circ}C$ for 24 hours has the safe strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.287-292
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• 1999

Mass concreting in cold weather environment should be focused on the control of thermal crack caused by high hydration heat rather than curing method for protecting from frost damage at early age because the thermal stress have much influence on the quality of structure placed in cold weather. Therefore, in this paper, the control of thermal crack of mass concrete in cold weather environment are dealt with preparing the practice plan for mass concrete and placing the concrete according to the plactice plan. According to the results, we can obtain good quality mass concrete without thermal crack caused by the difference of temperature between inner part and outer part.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.861-865
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• 2000

During the placement of concrete in cold weather, there are serious problems due to frozen concrete in the early stage. These adverse effects prevent the hardening of concrete. There are special mixing, handling, placement and crying to minimize problems. Heat crying and sheet curing have been used in crying steps in order to reduce problems. However, these curing methods are not efficient because it is hard to obtain the good quality and strength of concrete, and moreover, it needs additional works for curing. In this study, we evaluate the application of cold weather concrete by the dose antifreezing admixture in concrete mix design. Because it is easy to handle inconstruction site and improve the quality of concrete. As the result of this paper is to present a successful case for the practical use of cold weather concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.13.2-17
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• 2003

When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods to resolve these problems is to lower freezing temperature of concrete by the use of chemical admixture called Accelerators for Freeze Protection. In this study, it was the results of appling cold weather concrete using Accelerator for Freeze Protection in the Daewoo Trump world field. Before the application of the cold weather concrete using accelerator for freeze protection, we executed the some test in the laboratory and mock-up test in the field. We examined the manifestation of compressive strength complying with the amount of Accelerators for Freeze Protection and curing conditions, and then made a selection of most suitable amount of Accelerators for Freeze Protection.

• 한국구조물진단유지관리공학회 논문집
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• 제17권5호
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• pp.59-66
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• 2013

한중공사에 있어서 일반 콘크리트는 영하의 기온에서 타설할 경우 양호한 경화를 얻을 수 없으며, 저온에서 동해를 방지하고 경화성을 확보하기 위하여 내한방동제를 첨가하여 사용하고 있다. 초속경 콘크리트를 한중공사에 적용할 경우 초기 급속한 발열반응을 통하여 동해를 입기 전에 소요강도를 확보할 수 있을 것으로 판단된다. 최근 연구되고 있는 마그네시아인산염복합체는 초속경성이고 저온에서도 수화반응이 가능한 것으로 보고되고 있어 새로운 극한지용 건설재료로 사용할 수 있을 것이다. 따라서 본 연구에서는 극한지용 건설재료의 개발을 위한 연구로서, 마그네시아인산염복합체를 개발하고 이 복합체를 사용한 모르타르에 대해 온도의 영향을 고려한 재료물성 평가를 실시하여 적정 배합을 제안하였다.