• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.885-888
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• 2008

In recent years, the terminology "High-Performance Concrete(HPC)" has been introduced into the construction industry. Most high-performance concretes have a high cementitious content and a low water-cementitious material ratio. The proportions of the individual constituents vary depending on local preferences and local materials. Therefore, many trial batches are usually necessary before a successful mix is developed. The objective of this experiments is to investigate the fundamental properties of high performance concrete based binary cimentitious materials such as ordinary portland cement and ground granulated blast furnace slag. The results from the study will be utilized as the basic data and guideline in making standard mixproportions and the manufacture, construction work and quality control of HPC

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.322-328
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• 2014

In this study, revelation performance of concrete at early age according to types of cement, water reducing ratio of high performance superplasticizer and mixing of accelerator for early hydration was examined aiming for reduction of construction period of framework through securing strength at early age of concrete. It was observed that strength at early age, 5MPa in 12hours, 14MPa in 18hours, is secured by early strength improvement type cement and using promotion admixture for early hydration which are Sodium persulfate, Potassium hydroxide. Therefore cost reduction is expected to be possible in construction site by reducing construction period of frame work.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.337-340
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• 2002

부직포의 제조공정은 기본적으로 웹성형공정과 웹결합공정으로 구성되어 있다. 웹성형공정에는 단섬유를 중심으로 건식법과 습식법 및 장섬유를 중심으로 스펀본드법[1]이 있다. 웹결합공정에는 니들펀칭과 접착제, 열응착, 스펀레이스 및 스티치공정 등 여러공정법이 응용되고 있다. 이러한 공정의 선택은 개발목표로 하는 최종제품의 특성과 용도에 의해 결정된다. 일반적으로 동일중량을 기준에서 볼 때, 고강도 고강제조공정상 경량제품에는 주로 열융착방법을 선택하며 중량제품에는 니들펀칭공정을 사용하고 있으며 그 한계는 웹결합공정 특성상 약 150g/$m^2$ 내외이다. (중략)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.44-44
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• 2010

냉방기기의 고성능소형화를 촉진시키기 위해서는 고강도 고열전도성 알루미늄합금소재의 개발이 시급하다. Condenser용 튜브부품은 향후 더욱 소형화, 경량화 하는 방향으로 전개되며, 결국 목표로 하는 컨덴서용 튜브 소재적인 측면에서의 기능은 고강도, 고열전도, 압출성이 우수하여야 한다.

• Magazine of the Korean Society of Hazard Mitigation
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• v.3 no.3 s.10
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• pp.82-89
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• 2003

대만 국가과학위원회에서는 1998년에 지진재해 구조물 피해 사회경제적 손실을 위한 연구를 위해 HAZ-Taiwan 연구 project를 착수하였다. 관련 software인 TELES(Taiwan Earthquake Loss Estimation System)는 3가지 목표를 위해 다양한 입력 및 분석 module로 구성되어 있다. 1. 피해 지진후 재해 평가 2. 재해복구계획 및 가상 시나리오 제공 3. 재해보험을 포함한 재해대응방안 제시 본 논문은 초기재해평가에 이용될 분석 modules개발 및 적용에 초점을 맞추고 있으며, 분석 module은 지반운동강도 액상화 건물피해 및 사상자 평가분석을 포함하고 있다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11b
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• pp.663-668
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• 1996

하나로를 이용한 재료조사시험용 계장캡슐 개발에 앞서 캡슐 mock-up (96M-01K)을 제작하였으며, 이 캡슐 mock-up의 실제 하나로 조사시험공 장입시를 가정하여 강도 및 열적 건전성 평가를 수행하였다. 평가 결과 하나로 정상출력시 (30MW) 캡슐 mock-up 내 조사시료의 온도는 진공 및 heating system을 사용하여 279~473$^{\circ}C$ 범위로 조절될 수 있었으며, 목표 조사기간 동안 캡슐 mock-up은 강도적으로 허용기준을 충분히 만족함으로써 안전한 것으로 판명되었다. 향후 본 캡슐 mock-up을 이용한 노외 simulation 실험 등을 통하여 기존 캡슐 mock-up의 건전성을 확인한 후 이를 기준으로 하여 표준형 하나로 캡슐을 설계 .제작하고자 한다.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.95-102
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• 2010

In recent years, the demand for the development of high quality and cost effective materials, as well as the competition to ensure a diverse and sufficient amount of ready-mixed concrete, has been increasing rapidly. In this experiment, concretes made with different admixtures are blended with each other in different combinations and ratios, in order to identify potential problems. The first test was a slump level test, in which all of the concretes met the required numbers, as they also did in the test for air content. Plain organic acid concrete scored the highest in bleeding amount, but organic acid mix in general showed a similar outcome. In the early measurement of compressive strength, plain naphthalene concrete was the strongest. Of the blends, the 5:5 mix of organic acid and naphthalene was the strongest. In the standard measurement, the 5:5 mix of naphthalene and lignin was the strongest. Tensile strength tests revealed similar results. Length change rate proved to be greater in blended concrete than in plain concrete, and dry shrinkage rate was highest in the 7:3 ratio blends. Through SEM photo analysis, it was confirmed that the 7:3 ratio blends contained more micro-voids. In conclusion, with the exception of a specific few combinations, it was found that the blending of different types of concrete is undesirable due to the delayed coagulation time as well as the early decrease in strength.

• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.597-604
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• 2012

The present study assessed the $CO_2$ emissions of concrete according to the type and replacement ratio of supplementary cementitious materials (SCM) and concrete compressive strength using a comprehensive database including 2464 cement concrete specimens and 776 cement concrete mixes with different SCMs. The system studied in $CO_2$ assessment of concrete based on Korean lifecycle inventory was from cradle to pre-construction, which includes consistent materials, transportation and production phases. As the performance efficiency indicators, binder and $CO_2$ intensities were analyzed, and simple equations to evaluate the amount of $CO_2$ emission of concrete were then formulated as a function of concrete compressive strength and the replacement ratio of each SCM. Hence, the proposed equations are expected to be practical and useful as a guideline to determine the type and replacement ratio of SCM and unit content of binder in concrete mix design that can satisfy the target compressive strength and $CO_2$ reduction percentage relative to cement concrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.4
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• pp.67-74
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• 2015

In this study, effects of micropores on the freezing-thawing resistance of high volume slag concrete are reviewed. Concrete was made with slag which contains the ground granulated blast furnace slag(GGBS) and the pig iron preliminary treatment slag(PS) by replacing 0, 40, 70 %, then compressive strength, freezing-thawing resistance, micropores were reviewed. Also, specified design strength, target air contents were set. Deterioration was induced by using 14-day-age specimen which has low compressive strength for evaluating deterioration by freeze-thawing action. As results of the experiment, despite of specified design strength which has been set similarly and ensured target air contents, the pore size distribution of the concrete showed different results. Micropores in GGBS70 specimen have small amount of water which is likely to freeze because there is small amount of pore volume of 10~100 nm size at 0 cycle which has not been influenced by freezing-thawing. For these reasons, it was confirmed that the freezing-thawing resistance performance of GGBS70 is significantly superior than other specimens because relatively small expansion pressure is generated compared to the other specimens.

• Magazine of the Korea Concrete Institute
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• v.10 no.3
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• pp.165-173
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• 1998

투수성 콘크리트포장은 우천시 도로포장 노면의 배수, 차량 주행 안전성의 향상 및 소음의 저감등을 목적으로 개발된 포장이지만 주행환경 및 도로주변과의 환경조화에도 기여한다. 일반적인 배수성 아스팔트 콘크리트포장에서는 투수계수 1$\times$10-2cm/sec를 목표로 정하고 있으나 본 연구에서는 투수성 콘크리트포장의 실용화를 위한 연구의 일환으로 투수계수1$\times$10-1cm/sec를 목표로 정하여 골재의 최대치수, 잔골재율 및 단위시멘트량을 변화시킨 투수성 콘크리트의 공극률, 연속공극률 및 투수계수와 제강도를 측정한 결과에 대하여 고찰하였다. 투수성 콘크리트의 목표투수계수 1$\times$10-1cm/sec 일 때 공극률 및 연속공극률은 각각 15 %와 12%정도이며, 압축강도는 240kg/$\textrm{cm}^2$정도의값을 나타내었으며, 골재의 최대치수가 10~13mm일 경우, 잔골재율 10~20%, 단위시멘트량 380 kg/$\textrm{cm}^2$정도가 적절한 배합으로 생각된다.