• 한국안전학회지
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• 제14권2호
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• pp.122-126
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• 1999

In this study, using the temperature history analysis, the influences of the conductive values of wooden form, which are specified by Korean Standard for Concrete and ACI Practice Manual for Concrete, on the temperature history were examined. And, the calculated temperature history is compared with the measured temperature history. In the examination for the influences of the conductive values of wooden form, the value recommended by the Korean Standard can more closely predict the themperature history at the points which the variation of the boundary condition should be considered.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2010년도 춘계 학술논문 발표대회 1부
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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.

• 한국건축시공학회지
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• 제14권3호
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• pp.273-284
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• 2014

Ultra-high-performance concrete (UHPC) consists of cement, silica fume (SF), sand, fibers, water and superplasticizer. Typical water/binder ratios are 0.15 to 0.20 with 20 to 30% silica fume. In the production of ultra-high performance concrete, a significant temperature rise at an early age can be observed because of the higher cement content per unit mass of concrete. In this paper, by considering the production of calcium hydroxide in cement hydration and its consumption in the pozzolanic reaction, a numerical model is proposed to simulate the hydration of ultra-high performance concrete. The heat evolution rate of UHPC is determined from the contributions of cement hydration and the pozzolanic reaction. Furthermore, by combining a blended-cement hydration model with the finite-element method, the temperature history in the hardening of UHPC is evaluated using the degree of hydration of the cement and the silica fume. The predicted temperature-history curves were compared with experimental data, and a good correlation was found.

• 콘크리트학회논문집
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• 제12권2호
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• pp.79-87
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• 2000

The strength development of concrete is influenced by temperature and cement type which greatly affect hydration degree of cement. There is not pertinent concrete strength management methods for estimating the in-place strength of concrete. One such method is the maturity concept. The maturity concept is based on the fact that concrete gains strength with time as a result of the cement hydration and, thus the rate of hydration, as in any chemical reaction, depends primarily on the concrete temperature during hydration. Thus, the strength of concrete is function of its time-temperature history. This goals of the present study are to investigate a relationship between strength of high-fluidity concrete and maturity that is expressed as a function of an integral of the curing period and temperature, predict strength of concrete.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.794-799
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• 2009

The temperature control of in-place concrete is the most important factor for an early age of curing concrete. Heat stress of mass concrete caused by the heat of hydration can induce the crack of concrete, and a frost damage from cold weather casting concrete results defect on compressive strength and degradation of durability. Therefore, success and failure of concrete work is dependant on the measurement and control of concrete temperature. In addition, the compressive strength assessment of in-place concrete obtained from the maturity calculated from the history of temperature make a reduction of construction cycle time, possible. For that purpose, wireless temperature measuring system was developed to control temperature and assess strength of concrete. And, it was possible to monitor the temperature of concrete over 1km apart from site office and to take a proper measure; mesh-type network was developed for wireless sensor. Furthermore, curing control system that contains the program capable to calculate the maturity of concrete from the history of temperature and to assess the compressive strength of concrete was established. In this study, organization and practical method of developed curing control system are presented; base on in-place application case.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.119-122
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• 2009

As architectures have recently become high-risers and mega-structured, stable high strength products have been ensured. Accordingly, use of precast concrete accouplement has been increased in order to facilitate air compression and rationalize construction. Since not only external heating but a1so internal temperature rise caused by the accumulation of cement hydration heat in manufacturing process, precast concrete members with large cross-section used for high-rise mega-structure's columns and beams may exhibit different temperature history compared to the precast concrete members for wall and sub-floor with relatively small cross-sections. Therefore, this study aims to elucidate the characteristics of temperature history of mass concrete members cast with high-strength concrete fur precast concrete application. In this study, large cross-sectional precast concrete mock-up, unit cement quantity, and temperature histories in manufacturing precast concrete member under different curing condition were inclusively investigated.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.49-52
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• 2007

Recently, as architectural concrete structures become high-rise and megastructured, concrete become high-strengthened and, by ensuring products of more stability, air compression and rationalization of construction are required. In general, product management test of precast concrete member, specimen for management cured in the same condition with precast concrete member is substitutively used for strength test. However, large cross-sectional precast concrete members such as columns show large temperature increase in manufacturing process not only by external heating but also by concrete itself's hydration heating. Therefore, it is expected that specimen for management to predict strength and compression strength of precast concrete member shows different temperature history and strength characteristics. Concerning this, in order to suggest temperature history and strength characteristics of high strength mass concrete suitable for precast concrete application, this study comprises the inclusive investigations on the relations between management specimen with similar temperature history and core strength, and the strength characteristics per member cross-section dimensional value and per water-bonding material ratio value.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.56-57
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• 2013

In this study, in regard to concrete considering variety of admixture content rate, we evaluated property of adiabatic temperature rise. By setting up high temperature history, we evaluated effect to compression strength property of high strength concrete by early high temperature history. As a result, early high temperature history accelerated Hydration reaction of cement and contribute early strength development but it didn't accomplish performance objective in long-term aged.

• 콘크리트학회지
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• 제8권4호
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• pp.191-199
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• 1996

매스콘크리트 시공시 콘크리트의온도가 급격히 변화하면 콘크리트에는 균열이 발생하게 된다. 매스콘크리트를 타설한 후에는 구조물의 주변환경조건이 콘크리트의 온도를 변화시키게 된다. 그러나 아직도 주변환경조건을 고려하여 콘크리트의 온도이력을 엄밀하게 해석할 수 있는 해석기법이 개발되지 않은 상황이다. 본 연구에서는 대기온도, 양생온도, 거푸집재료, 거푸집의 존치 및 제거, 추가양생 등 주변환경조건이 매스콘크리트 온도이력에 미치는 영향을 정량적으로 해석하기 위하여 유한요소정식와에 열전달계수, 주변환경조건 및 거푸집조건을 도입하였고 이를 해석할 수 있는 알고리즘과 해석프로그램을 개발하였다. 본 연구의 수치모형 해석값을 모형실험값, 타연구 모형실험값 및 기존의 범용프로그램에 의한 해석값과 비교한 결과로부터 본 연구의 온도해석이론의 타당성 및 정확도를 분석하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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• pp.238-242
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• 1994

Recently, construction of mass concrete structures except Dam are increased very often. Generation heat due to the hydrating reaction of mass concrete is generally larger than the heat released to the air, foundations and the exist structures. Therefore, internal temperature of mass concrete is remarkably risen and temperature gap between center and surface is extended by various effect. It this gap get large, the crack may be occurred. This crack must be controlled as little as possible to ensure the soundness and durability of structure. Firstly, Temperature rising history of Mass concrete is expected correctly to constrain the crack of mass concrete. So, objectives of this research is to quantify the effects of hydration temperature for the purpose of evaluating accurately the temperature history of mass concrete.