• 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.

• 콘크리트학회논문집
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• 제17권2호
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• pp.237-245
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• 2005

본 연구에서는 우리나라 기상청의 기온자료를 이용하여 시간변화에 따른 각 지역의 한중콘크리트 적용기간을 KCI, ACI 및 AIJ 방법에 따라 산정한 후 동방법의 기존연구결과와 비교 분석함으로써 시간변화에 따른 한중콘크리트 적용기간의 변화를 분석하고자 하였다. 연구결과에 따르면, KCI에 의한 적용기간은 평균 9.5순으로 나타났고, ACI에 의한 적용기간은 10.1순 그리고 AIJ에 의한 적용기간은 9.2순으로 산정되었다. 시간변화에 따른 적용기간으로서 KCI 및 ACI 규정에 의한 본연구의 적용기간은 10년전의 종전 연구보다 약 5${\~}$6일 정도 짧아진 것으로 확인되었으나, AIJ 규정에 의한 적용기간은 종전의 연구와 거의 차이가 없었고, 단, 김의 연구와 비교할 경우 약 3일 정도 짧아지는 것으로 나타났다. 한편, 지역별로는 남부지방의 경우 종전연구에 비하여 한중콘크리트 적용기간이 비교적 많이 단축되었는데,. 이는 지구의 온난화에 의한 평균기온의 상승으로 인한 것으로 사료된다.

• 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 1995년도 봄 학술발표회 논문집
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• pp.154-159
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• 1995

Cold weather concrete presents the many characteristic variation of quality, according to the mixing and cooling point, the cooling time and the quantity of air besides the compressive strength of concrete. Thus, in this study to verify the character of cold-weather concrete we make the concrete specimens at laboratory and cool them at cooling-melting machine and then test the 7days compressive strength of them, with the variation of compressive strength of concrete, cooling point, cooling time, cooling weather and air quantity. At the results, the compressive strength of concrete decrease in the case of early cooling point, long cooling time, low cooling temperature and the low design compressive strength

• 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.

• 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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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• pp.57-60
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• 2008

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• 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 2001년도 가을 학술발표회 논문집
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• pp.629-634
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• 2001

Recently, to consider financial and constructive aspect, usage of Admixture, like Blast-Furnace Slag and Fly-Ash, are increased. Also the use of cold-weather-concrete is increased. Blast-furnace Slag, a by-product of steel industry, have many advantage, to reduce the heat of hydration, increase in ultimate strength and etc. But it also reduces early-age strength, so it is prevented from using of Blast-Furnace Slag at cold-weather-concrete. In this study, for the purpose of increasing usage of Blast-Furnace Slag at cold-weather-concrete, it is investigated the strength properties of concrete subjected to frost damage for the cause of early age curing. According to this study, if early curing is carried out before having frost damage, the strength of concrete, subjected to frost damage, is recovered. And that properties is not connected with the frost cause.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.645-650
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• 2003

The purpose of this study is to provide the optimum mix design of cold weather concrete to be placed at the foundation structures in substation. The basic performance tests including slump and slump flow, air content, compressive strength and freezing & thawing resistance were conducted for cold weather concrete by varying with W/C ratios such as 40%, 50% and 60% and air contents such as 3%, 4%, 5% and 6%. The effect on durability of concrete corresponding to the increasing amount of air content and W/C ratio was evaluated and the optimum mix design was recommended. From this study, the concrete mix design containing 6% of air content and 45% of W/C ratio is recommended for the foundation concrete of substation.