• 콘크리트학회지
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• 제7권6호
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• pp.176-185
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• 1995

매스콘크리트 구조물에서 시멘트의 수화발열반응에 발생된 열은 약재령 콘크리트에서 내부온도의 증가와 체적변화를 일으키게 된다. 이와 같은 온도증가에 외부구속조건이 존재하게 되면, 구조물에는 인장응력이 발생하고 이는 구조물에 균열을 일으킬 수 있다. 따라서 매스콘크리트 구조물 건설시 수화열에 의한 온도증가를 제어하기 위해 다양한 시공기법을 이용하고 있으며, 이들 공법 중 하나가 관에 냉각수를 유입시켜 온도를 하강시키는 파이프쿨링 공법이다. 이 논문의 목적은 파이프쿨링을 실시할 때 수화열로 인한 온도이력을 모사할 수 있는 유한요소해석 프로그램을 개발하는 것이다. 이 연구에서 개발된 해석 프로그램의 결과와 실제 구조물의 기초부(11$\times$22cm)의 실측 결과가 잘 일치함을 보였다. 따라서 여기서 제시된 방법은 파이프쿨링으로 인한 콘크리트의 수화온도 예측에 유용하게 이용될 수 있을 것으로 판단된다.

• 콘크리트학회논문집
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• 제16권2호
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• pp.147-154
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• 2004

국내의 경우 건설생산현장에서 고유동콘크리트의 제조시 주로 나프탈렌계 및 멜라민계가 적용되고 있으며, 또한 최근에는 콘크리트의 요구성능을 확보하기 위하여 이러한 두 성분을 혼합하여 적용하는 사례도 나타나고 있다. 따라서 본 연구에서는 고유동콘크리트의 유동특성에 영향을 미치는 고성능감수제의 구성비율을 비교$\cdot$분석함으로서 혼합형 고성능감수제의 현장적용시 적용방법 및 품질기준 확립을 위한 기초적인 자료를 제시하기 위하여 고성능감수제를 분산제의 구성비율에 따라 N, NM, MN, M의 4수준으로 설정하였다. 그 결과 고성능감수제 구성비율에 따른 페이스트의 유동특성은 나프탈렌의 구성비율이 증가할수록 상대플로우면적비 및 흡착률이 증가하고 있어 유동성이 우수하게 나타났으며 멜라민 구성비율이 증가할수록 점성이 높아지는 것으로 나타났다. 나프탈렌-멜라민 혼합형 고성능감수제의 경우 유동성 및 간극통과성을 포함한 고유동 특성과 응결시간에 있어서 상대적으로 양호한 성능을 나타내고 있어 고유동콘크리트 제조시 고성능감수제를 구성하는 주요성분을 적절하게 혼합하여 사용함으로서 고성능감수제의 효율적인 성능향상이 가능할 것으로 사료된다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.711-715
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• 2003

For Taejon LNG Pilot Cavern being constructed to verify the technical aspects for storing LNG in lined rock cavern, efficiency tests of groundwater drainage system composed of many pumps and boreholes were performed around the cavern before and after the construction of concrete lining. Through evaluation of water balance and monitoring of pressures and flowrates, even if the present drainage system is very good for reducing water entries into the cavern, non-negligible water is still flowing in the floor of the cavern concrete due to heavy rainfall. To improve the drainage efficiency, additional drainage holes and some grouting were planned.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.241-246
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• 1997

This paper tried to catch the fluidity and rheology nature of paste, using the W/P, flay-ash and additional amount of superplasticizing agent as experimental factor. Form result of experiment, as the amount of superplasticizing agent increased, fluidity increased and the rheology decreased. As the substitutional ratio increased fluidity decreased, the rheology tended to increase, additional amount of agent to gain high flowing range is different according to w/p, but this experiment shows about 0.5~1.0% in fly-ash 10~30% substitutional range, 1.0~1.5% in fly-ash 50%.

• 한국건축시공학회지
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• 제5권2호
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• pp.131-138
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• 2005

Most concrete is recently made of an aggregate which is properly absorbed, and carried in it in order to do capability at every fields. We have been close to demand new rapability of high flowing and enduring for specific concretes. That is difficult to cope with claiming the efficiency on deterioration from lack of a high quality aggregate. Therefore, For solving the problems we apply to a packing method for using dried materials. That is to say that it is a kind of making into an instant. In this study. There is a purpose to present fundamental data, comparing and analyzing a phenomenon of aggregate's absorption following the rate of adding water, for using existing materials.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.45-48
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• 2003

Most concrete is recently made of an aggregate which is properly absorbed, and carried in it in order to do capability at every fields. We have been close to demand new capability of high flowing and enduring for specific concretes. That is difficult to cope with claiming the efficiency on deterioration from lack of a high quality aggregate. Therefore, For solving the problems we apply to a packing method for using dried materials. That is to say it is a kind of making into an instant. In this study, There is a purpose to present fundamental data, comparing and analyzing a phenomenon about aggregate's absorption following the rate of adding water, for using existing materials.

• 한국건축시공학회지
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• 제3권4호
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• pp.119-122
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• 2003

Most concrete is recently made of an aggregate which is properly absorbed, and carried in it in order to do capability at every fields. We have been close to demand new capability of high flowing and enduring for specific concretes. That is difficult to cope with claiming the efficiency on deterioration from lack of a high quality aggregate Therefore, For solving the problems we apply to a packing method for using dried materials. That is to say it is a kind of making into an instant. In this study, There is a purpose to present fundamental data, comparing and analyzing a phenomenon about aggregate's absorption following the rate of adding water, for using existing materials.

• International Journal of Concrete Structures and Materials
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• 제6권2호
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• pp.65-78
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• 2012

An experimental study was carried out to evaluate fresh properties of a moderately high-strength (high-flowing) self-compacting concrete (SCC) and to investigate shear behavior and performance of deep beams made with SCC. Fresh and hardened properties of normal concrete (NC) and SCC were evaluated. The workability and compacting ability were observed based on casting time and number of surface cavities, respectively. Four-point loading tests on four deep beams (two made with SCC and two with NC) were then conducted to investigate their shear behavior and performance. Shear behavior and performance of beams having two different web reinforcements in shear were systematically investigated in terms of crack pattern, failure mode, and load-deflection response. It was found from the tests that the SCC specimen having a normal shear reinforcement condition exhibited a slightly higher load carrying capacity than the corresponding NC specimen, while the SCC specimen having congested shear reinforcement condition showed a similar load carrying capacity to the corresponding NC specimen. In addition, a comparative study between the present experimental results and theoretical results in accordance with ACI 318 (Building Code Requirements for Reinforced Concrete (ACI 318-89) and Commentary-ACI 318R-89, 1999), Hsu-Mau's explicit method (Hsu, Cem Concr Compos 20:419-435, 1998; Mau and Hsu, Struct J Am Concr Inst 86:516-523, 1989) and strut-and-tie model suggested by Uribe and Alcocer (2002) based on ACI 318 Appendix A (2008) was carried out to assess the applicability of the aforementioned methods to predict the shear strength of SCC specimens.

• 한국수소및신에너지학회논문집
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• 제32권5호
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• pp.365-373
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• 2021

In this study, evaporation of LN2 non-spreading pool on concrete plate was dealt with experimentally. The thermophysical properties of concrete, which is a composite material, were obtained by minimizing the difference between the numerical analysis results obtained from the assumed properties and the results from experiments. The thermal energy required for evaporation of the liquid pool is supplied from the concrete plate and the wall of the container. As a result of the measurement, the thermal energy flowing in from the wall was negligible compared to the one supplied from the concrete plate. It was found that the measured evaporation rate of the liquid pool by the heat energy supplied through the concrete plate agrees well with the PTC model except for the initial section of the experiment. The validity of the semi-infinite assumption and the one-dimensional assumption, which are the main conditions of the PTC model, was also verified through experiments. The evaporation rate model in the non-spreading pool discussed in this study can provide a basic frame for the one in the spreading pool, which is a meaningful result considering that the spreading pool is very realistic compared to the non-spreading pool.

• 한국농공학회지
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• 제12권4호
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• pp.2090-2123
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• 1970

This paper is a report on the research of experimental model test of Andong Fill Dam, which has been planned by the Government of Korea as a project, of its over-flowing capacity in spillway, creation of minus pressure and structure of anti-water impulse in over-flow weir. Andong Fill Dam is one of the project of master development plant for water resources, locating at Nakdong River side of Korea, and is aimed to have a multi-purpose dam for flood-control, irrigation, water power, urban and industrial water supply. This dam is planned to erect in fill-dam type due to the improper soil foundation and condition for concrete dam. The refore for the proper and advantageous points, this is designed as center core fill dam. By a model minimized of Andong Fill Dam, held an experimental model test on water quentity of reservir, discharges of overflow part, low pressure and anti-water impulse of overflow part, which was conducted an experiment by flowing aspects through each section of spillway to find the changes of water pressure and that of water level, and corrected the section of each part in order to conduct a check on the creation of minus pressure not to be over acted to the allowable bundary of the section structure; and for the prevention of concentated scouring at the down stream side of flow.