• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.19-21
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• 2012

This paper was to investigate the effect of incinerator ash on engineering properties of the high volume blast furnace slag concrete through Mock-up test. Test results revealed that the use of recycled aggregates resulted in increase of slump compared with the OPC concrete. But, the use of recycled aggregates did not affect the results of air contents and chloride contents. The use of recycled aggregates showed shortening of setting time of high volume blast furnace slag concrete. When the recycled aggregate was used, delay in strength development at early age happened with high volume blast furnace slag concrete compared with that of OPC concrete.

• 한국의류학회지
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• 제21권1호
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• pp.217-227
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• 1997

Costume of each age reflects its own history. Military costume is an reflections of war, social and geometrical background. Soldiers on their uniforms were at the battlefields with their lives and country on their shoulders. The main purpose of this writing is to study military costume of ancient empires in historical Point of view including especially those of Egypt, Mesopotamia, Crete, Greece, Etruria, Rome. As we will see, ancient military costume developed from earlier stages of uniforms into military costume in various ways. The types of military costume formed itself gradually but rapidly into sophisticated, useful, and excellent quality clothes. Military costume of early ancient empires signified its strength and were actual and symbolic costume that determined life and death, glory and disgrace.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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• pp.133-138
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• 1998

The purpose of this study is to offer basic information of fly ash concrete for field application. Through before study and fly ash in mortar, various properties as fly ash ratio in concrete were checked according to the experimental result, slump was increased and entrained air quantity was decreased as fly ash ratio is increased in fresh concrete. In hardened concrete, strength development of plain concrete(W/B 50%) was slower than water-reduced concrete(W/B 40%) at early age. Especially water-reduced concrete was remarkabily faster than no fly ash in concrete. Moduls of stastic elasticity and stress-strain relationship of fly ash in concrete nearly were effect on no fly ash concrete.

• 한국안전학회지
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• 제19권4호
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• pp.161-165
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• 2004

철근콘크리트조 공사의 안전성과 효율성은 동바리-슬래브거푸집의 최적의 운영에 달려있다. 철근콘크리트공사에서의 사고는 주로 가설공사에 과도한 하중이 작용하였거나 동바리를 조기에 철거하기 때문에 발생한다. 콘크리트의 조기압축강도발현이 공사중구조체의 안전에 중요하다. 슬래브-동바리의 상호작용에 관한 연구는 주로 무량슬래브 구조에 대하여 이루어 졌다. 본 연구에서는 전단벽식 철근콘크리트조 아파트에서 슬래브와 동바리에서의 하중분포를 유한요소법을 이용하여 조사하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.435-436
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• 2009

본 논문의 목적은 PTCP포장공법에 적용하기 위하여 실리카흄과 플라이애시가 혼합된 고성능 콘크리트를 개발하는 것이다. 실험결과 실리카흄 혼입에 따라 조기재령 압축강도가 증진되었고, 투수저항성이 ASTM C 1202 기준 "Low"에서 "Very Low" 등급으로 향상되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.100-101
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• 2016

The fineness degree of Ordinary Portland Cement (OPC henceforth) usually used in Korea's construction sites, is designated as over 2,800㎠/g. But the higher the fineness, the surface area of hydration reaction on water increases as well, resulting in large early age strength and high-intensity; so the trend is to prefer a high degree of fineness. But from a pore-space filling perspective, fine-particled cement is not always beneficial to intensity. Therefore in this study artificial modifications were given to cement fineness to analyze the effect of various fineness changes on the liquidity, air quantity and intensity of lean mixture cement mortar. As a result, the greater the degree of fineness, the better the cement was, with fine particle+OPC having the most satisfactory results due to consecutive particle distribution.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.26-27
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• 2016

This study analyzes the engineering characteristics of mortar according to admixture replacement ratios in cement mortar in a high-intensity ternary system, and changes in FA and BS combination ratios, in order to deduce the optimal combination ratio of FA and BS. Results showed that due to the characteristics of unhardened mortar, flow rate increased with the increase in admixture replacement and FA combination ratios, whereas air quantity decreased and setting time was delayed. Due to the characteristics of light mortar, compression strength decreased at early material ages as the overall combination ratio of FA increased. The FA : BS combination ratio was 2 : 3 on day 28 of material age, proving the best and potentially optimal combination ratio.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.245-246
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• 2012

The analysis of microstructure is essential to understand the material behavior such as shrinkage, strength, and permeability. In this study, three different easy-to-apply specimen preparation methods for the mercury intrusion analysis were chosen, and their effectiveness in removing pore water and thus impeding further hydration was evaluated. As a result, it was found that the direct freeze-drying was the most effective among the three methods.

• Structural Engineering and Mechanics
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• 제37권3호
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• pp.321-330
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• 2011

Long-term properties of concrete affect structures in many respects, not excepting dynamic behaviors. This paper investigates the influence of concrete creep on the dynamic behaviors of concrete filled steel tube (CFT) arch bridges, by means of combining the analytical method for the creep of axially compressed CFT members, which is based on Model B3 for concrete creep, with the finite element model of CFT arch bridges. By this approach, the changes of the stress and strain of each element in the bridge with time can be obtained and then transformed into damping and stiffness matrices in the dynamic equation involved in the finite element model at different times. A numerical example of a long-span half-through CFT arch bridge shows that creep influences the natural vibration characteristics and seismic responses of the bridge considerably, especially in the early age. In addition, parameter analysis demonstrates that concrete composition, compressive strength and steel ratio have an obvious effect on the seismic response of the CFT arch bridge.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1248-1251
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• 2000

Recently, the yearly amount of remicon used in Korea is approximately one hundred million cubic meter, and it caused a by-product, remicon waste sludge. The sludge produced by washing mixers or drums of remicon trucks is restrained by the law for waste disposal because its pH is over 12, so the expense for waste disposal is needed. Until now, the waste sludge water has been recycled and used for concrete materials as sludge water which is limited to 3% of cement unit weight. However, the study on the properties of the concrete mixed with this waste sludge is so insufficient that the quality of them can be hardly trusted. Therefore, the study on that will be discussed.