• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.66-71
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• 1998

Recently, it has been increased to construct massive concrete structures, like under-ground structure, offshore structure etc., ie. concrete construction have become larger and higher and are demanding lower heat concrete to prevent thermal cracking. It has been progressed to replace cements with fly-ash and slag to lower heat of hydration, but it is hard to control quality of the mineral admixtures in stage of adjusting of real construction. Application of low heat portland(Belite Rich) cement for the mass concrete is the best solution to satisfied those requirements. Here are explained the basic properties of fresh concrete as well as hardened concrete of using low heat portland cement(LHPC). Also, we compare the results of adiabatic temperature rise test using LHPC and OPC.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.619-624
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• 1999

The purpose of this study is to provide the optimum mix design of fly ash concrete to be placed at the concrete face rockfill dam for pumped storage power plats. The basic performance tests including compressive strength, modulus of elasticity, unit weight, coefficient of thermal expansion, shrinkage, adiabatic temperature rise and analysis of thermal stress were conducted for fly ash concrete. From this study, the fly ash concrete represented the better results in the aspects of basic performance and economy than ordinary portland cement concrete. Especially the concrete mix design containing 15% of fly ash is recommended to be applied in the construction of the concrete face rockfill dam for pumped storage power plants.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.5-8
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• 2006

In this study, various fundamental experiments including durability and time-dependent deformation are performed to compile a database for a utilization of high-strength concrete for PSC bridges. In the mix design, concrete strength at early age when prestressing forces are introduced to the PSC member and slumpflow suitable for pumping of concrete are considered to make a concrete fit for PSC bridges. The main parameters investigated are the kinds and replacement ratios of mineral admixtures and low-heat cement. Experimental tests on durability include penetration of chloride ions, freezing-thawing, combined deterioration, and simple adiabatic temperature rise test. In addition, time-dependent deformation such as creep, drying and autogenous shrinkage, which is particularly important factor in the design and construction of PSC bridges, is tested and analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.189-190
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• 2010

Yeoju-Bo is a large massive concrete structures that require the reduction of working period of construction. In this study, we optimized the mix proportion of internal/external concrete and physical properties like compressive strength, semi adiabatic temperature rise in laboratory. And we also performed thermal analysis to verify the thermal cracking. Lastly we measured the hydration heat and the thermal cracking in site to verify the safety of massive concrete structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.291-292
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• 2010

In this study, high-strength concrete mixtures were made with blast-furnace slag of 50% and 70% replacement level to evaluate material properties including compressive strength development, adiabatic temperature rise, autogenous shrinkage and chloride-ion migration coefficient. Test results showed that the use of high percentage blast-furnace slag in high-strength concrete can reduce heat of hydration and chloride-ion migration coefficient, result in control thermal cracking and improve durability performance especially under high corrosive environment.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.177-187
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• 1998

최근 국내에서 해양 구조물, 장대 교량의 하부구조물, LNG저장탱크 등 매스콘크리트의 증가추세에 따라 구조물의 고내구성과 관련하여 시멘트의수화열에 의한 온도균열의 발생을 최소화 시킬 수 있는 3성분계 혼합형 저발열시멘트가 개발되어 실 구조물의 적용단계에 있으나, 저발열시멘트가 개발되어 실 구조물의 적용단계에 있으나 저발열시멘트의 특성에 대한 전반적인 연구보고가 국내에서는 미진한 실정이다. 따라서 본 연구에서는 3성분계 혼합형 저발열시멘트의 특성 및 코\ulcorner리트의기초물성을 1종 보통포틀랜트 시멘트, 5종 내황산염시멘트, 슬래그시멘트와 비교하였다. 글 결과 저발열 콘크리트의 찹축강도는 초기재령에서 강도발현률이 적은 반면 장기강도발현률은 상당히 큰 경향을 보였다. 또한 수화열은 1종시멘트를 사용한 콘크리트에 비하여 1/3~1/2정도로 매스콘크리트의 수화열을 대폭적으로 저감시킬 수 있을 뿐만 아니라 염소이온에 대한 저항성이 상대적으로 높게 나타나 거대 해양 구조물의 적용에 매우 유리한 시멘트로 판단되었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.33-34
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• 2018

As a result of measuring the compressive strength and semi-adiabatic temperature rise of the mixed mortar, it was confirmed that the mortar mixed with the hydration heat reducing material is effective. On the other hand, the compressive strength showed similar strength to that of moderate heat Portland cement until the age 7 days, but after that, the tendency of the strength development to be delayed was confirmed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.758-761
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• 2010

본 연구에서는 원전격납구조물과 같이 고품질의 대형 매스콘크리트의 설계, 시공, 품질예측 및 관리에 필요한 구조물 건전성 평가시스템 구축의 일환으로 수화열 예측 프로그램을 개발하였다. 개발된 수화열 예측 프로그램은 국내에서 생산된 시멘트 및 결합재의 화학조성성분, 분말도와 같은 기초정보 및 배합정보를 입력하여 경시변화에 따른 수화발열량을 계산하는 방식으로서 기존의 연구결과를 바탕으로 개발되었다. 개발된 프로그램은 배합환경조건을 고려하여 초기배합온도 3종류(10, 20, $30^{\circ}C$)로 실험한 단열온도상승 실험 결과와 비교해 보았으며, 좋은 상관성을 나타냄을 확인할 수 있었다.

• Journal of the Korea Concrete Institute
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• v.25 no.4
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• pp.411-418
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• 2013

Recently, in order to reduce a damage of chloride attack and hydration heat in marine concrete structures, blended cement in mixing the marine concrete is widely used. Long term strength development is distinct in concrete with blended cement and it also has excellent resistance to chloride attack and reduction of hydration heat. However, blended cement has a characteristic of relatively low compressive strength in early age of 28 days. On the other hand, a high level of compressive strength is required in the Standard Specification for marine concrete mix design. Such concrete mix design satisfying Standard Specification is effective to chloride attack but disadvantageous for hydration heat reduction due to large quantity of binder. In this study, the material properties of marine concrete considering water-binder ratio and binder type are experimentally investigated. Through the research results, compressive strength in blended cement at the age of 56 days is similar although it has smaller compressive strength at the age of 28 days compared with result of OPC (ordinary portland cement). Even though blended cement has a large water-binder ratio and small unit of binder content, chloride ion diffusion coefficient is still small and hydration heat is also found to be reduced. For meeting the required compressive strength in Standard Specification for marine concrete at 28 days, the increased unit content of binder is needed but the increased hydration heat is also expected.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.99-102
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• 2008

This study investigates the properties of the flow, air content, strength, hydration heat, and the autogenous shrinkage, and the results are summarized as following. As a properties of fresh concrete, the flow increased and the air content decreased as the replacement ratio of BS increased. The time of set delayed as the replacement ratio of BS increased by latent hydraulicity. The compressive strength of hardening concrete was smaller than OPC as the replacement ratio of BS increased at young concrete, however it was more than equal after 28th day and from then on. The rising temperature ratio which occurs by simplicity insulation decreased as the replacement ratio of BS increased, but it increased by latent hydraulicity reaction at the latter half. The length ratio of autogenous shrinkage of OPC was 319×10^-6, however it was shorter when the replacement ratio was 40% as showing 290×10^-6.