• 한국건설순환자원학회지
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• 제17권1호
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• pp.22-27
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• 2022

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
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• pp.17-20
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• 2005

This paper reported the temperature history of concrete placed at deck plate slab under cold climate condition by varying with surface insulating type. No curing sheet and simple insulation curing including non-woven fabric, double layer bubble sheet, the combination of double layer bubble sheet and non-woven fabric dropped temperature below zero within 24 hours, which caused frost damage at early age. On the other hand, the combination of double layer bubble sheet and non-woven fabric and double layer bubble sheet and styrofoam maintained minimum temperature above $4^{\circ}C\;and\;8^{\circ}C$, respectively. Based on core test results compressive strength of concrete with the combination of double layer bubble sheet and non-woven fabric and double layer bubble sheet and styrofoam was higher than those with other curing method due to good insulation effect.

• 한국건축시공학회지
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• 제17권1호
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• pp.73-81
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• 2017

본 연구는 기상자료를 토대로 우리나라 각 지역별 한중 콘크리트 적용기간을 KCI 및 AIJ 규정에 의한 방법으로 각각 산정하고 초기동해 위험일을 각 지역 및 온도 단계별로 제안하고자 하였다. 한중 콘크리트 적용기간의 경우 최근 5년간의 기상자료를 토대로 조사한 결과와 종전의 연구결과를 비교하였다. 연구결과에 따르면 국내 91개 지역의 한중 콘크리트 적용기간은 평균 98일로 조사되었고, 고위도 지역일수록, 산악 및 내륙지역일수록 적용기간은 증가되는 것으로 나타났으며, 종전 연구 대비 본 연구의 적용기간이 1~2일 정도 감소되는 것으로 나타났다. 지구온난화, 도시화 등의 영향으로 판단된다. 초기동해 위험일의 경우 $-5^{\circ}C$, $-2^{\circ}C$ 및 $0^{\circ}C$ 단계별로 시작일 및 종료일을 제시하였으며, 이를 토대로 $0^{\circ}C$ 이하 출현일 수, 출현일 및 평균 추위도를 제시하였다. 본 연구 범위에서 제시된 초기동해 위험일은 KCI에 의한 한중콘크리트 적용기간보다 길게 나타난 지역이 다수 존재하여 한중콘크리트 적용기간 이외에도 초기동해 위험이 있음을 확인할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.913-918
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• 2001

This paper investigates insulating effects and strength properties of concrete under cold climate carrying out the experiment with insulating forms on the slab member. According to test results, under $-10^{\circ}C$ of outer temperature, the surface of concrete exposed to outer temperature goes below zero after 10hours since exposed. And, the surface of concrete covered with vinyl and blanket goes below zero after 42hours. However, the surface of concrete covered with insulating materials such as polystyrene foam does not drop below zero until 55hours. And, according to coring sample strength test, compressive strength cured with insulation shows much higher strength than no insulation curing condition and vinyl and blanket curing condition.

• 콘크리트학회논문집
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• 제15권3호
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• pp.392-399
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• 2003

본 연구는 한중콘크리트 시공 시 초기보온 대책 중 가장 손쉽고 경제적일 것으로 사료되는 단열 보온양생을 대상으로 하였다. 실험은 한중콘크리트 시공조건을 상정하여 기존 거푸집과 각종 단열재 조합에 따른 단열거푸집간의 온도이력을 검토하여 효율적인 단열거푸집을 개발하고자 하였다. 실험결과 $-10^{\circ}C$ 일정인 외기온도 조건에서 벽용 거푸집의 경우, 일반 유로폼인 경우는 초기 24시간 이전에 급속한 온도저하에 의해 $0^{\circ}C$ 이하로 약 7시간 정도 지속되었고, PP＋스티로폼＋합판인 경우는 영상의 온도를 유지하고, 강도발현도 우수하며, 단열거푸집간 비교적 가격도 저렴하여 우수한 단열거푸집임이 밝혀졌다. 슬래브용 거푸집 실험의 경우, 하부는 단열거푸집으로 고정하고, 콘크리트 표면 양생방법을 달리하였을 때, 콘크리트의 온도이력을 측정한 결과, 노출시킨 경우 약 10시간 이후부터 영하로 저하하였고, 비닐+양생포의 경우 약 42시간 이후부터 영하로 저하하였다. 반면, 비닐＋스티로폼+양생포를 사용한 양생의 경우에는 약 55시간 이후부터 영하로 저하하여 노출이나 일반적으로 많이 사용되는 비닐＋양생포와 비교하여 우수한 단열효과임이 밝혀졌다. 7일 및 28일에 있어 슬래브의 코어 압축강도를 측정한 결과는 단열재를 사용하였을 때 크게 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.231-236
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• 2001

In this paper, tests are carried out in order to investigate the validities of anti-freeze agent, which is developed using waste coolant and existing anti-freeze agent through previous study, under various W/C and contents. According to test results, adequate dosage of developed anti-freeze agent shows positive performance in slump, air content and chloride contents in the mixture of 40% and 50% of W/C, accelerates setting time and drops the freezing temperature of concrete. Meanwhile, in the region of 30% of W/C, followings can be indicated that increasing the contents of anti-freeze agent leads to reduce fluidity, rapid setting and excessive chloride contents. Improved strength gain is shown when anti-freeze agent is used with in 8%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.663-668
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• 2002

In this paper, insulating effects and strength development of concrete placed at mock up model structure are discussed using anti freezing agent and insulating forms. According to test results, concrete containing 8% of anti freezing agent shows lower freezing temperature, earlier setting time and higher strength development than plain concrete. As for the temperature history of mock up structures, when plain concrete is placed at euro form, the temperature drops to -4${\circ}$ before early 24 hours, and when concrete containing anti freeze agent at euro form, it to -3${\circ}$ before early 24 hours. Nevertheless, when concrete containing anti freeze agent is placed at insulating form, it does not go below zero, and the concrete containing anti freeze agent enhances higher strength development.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2001년도 학술논문발표회
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• pp.76-81
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• 2001

Recently, the structure is higher and larger, so that the application of high-strength concrete is increased, And as the development of construction skills, it is possible to place during the winter. Concrete work during winter is indispensible to shorten time of completion and cut costs. When concrete work during winter is placed, it has anxiety that concrete freeze at low temperature. As repetition of concrete's freezing cause reduction of durability, it is necessary for mixing to pay attention to air content and W/C ratios. Accordingly, in this study, we estimate the frost resistance by air content and W/C ratios, and development of strength after early-frost damage in the high-strength concrete during the cold weather. In this study, it could be confirmed that factors which were air content, W/C ratios and early curing period, affected on the frost resistance.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.11-12
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• 2011

This study examine Effect of Change of Compressive Strength of Concrete Members with Insulating Gang form on Temperature History of Concrete Positions. Test show, insulating gang forms differences and gang forms have 10℃ on peak point temperature of surface and Center if temperature history have 24Mpa by change of compressive strength. In addition, there have 14℃(16℃) on peak point temperature of surface and Center if temperature history have 40(60)Mpa. Therefore, insulating gang forms have an effect insulating performance.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.71-74
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• 2007

This study investigates the fundamental properties of high strength concrete made with various blame values of cement, manufactured by the particle screening method in a pulverizing process. Test showed that concrete using lower blame of cement, such as large particle (L) and both ordinary and large particle (OL), increased the fluidity of fresh concrete. As tine progressive, it was noticeable that the specimens using ordinary cement (OPC) gradually decreased the fluidity, but the other specimens showed the sudden decline until 30 minutes, which is followed by a gradual decrease after 60 minutes. For the setting time, higher blaine of cement accelerated the initial and final setting time, especially concrete using minute size of cement (M) was 10 hours faster than OPC. Compressive strength of L exhibited similar value at 1 days as to that of strength in OPC at 3 days. Importantly, the specimens using M also revealed the similar strength value, regardless of curing temperature between $-5^{\circ}C$ and $20^{\circ}C$, which means that using this minute particle of cement in concrete can secure the strength development even in the lower temperature circumstance. Therefore it is clear that using OPC+M simultaneously at cold weather concreting can resist the early frost and develop the early strength of concrete.