• 한국건축시공학회지
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• 제3권4호
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• pp.79-86
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• 2003

The purpose of study is to offer base data for high fluid concrete mix property, as grasp effect of aggregate to reach much more effect for producing high fluid concrete. For this study, there are three types of combined aggregates, river sand + river aggregate(type A), river sand + crusted aggregate(type B), washed sea sand + crushed aggregate(type C) and take a factor, water-contents, water-binder ratio and S/a. And so, we had following conclusion, resulting application-ability of high fluid mortar by K-slump tester to use a handy consistency measuring instrument. And so, we had following conclusion, resulting application-ability of high fluid concrete by K-slump tester to use a handy consistency measuring instrument. 1) In cafe of regular water binder ratio, high fluid concrete suffered much effect of combined aggregates and water binder ratio. Range of water binder ratio by combined aggregates is w/b 0.4 downward(type A and B), w/b 0.35 downward(type C). 2) Water contents to need for producing high fluid concrete is minimum 170kg/$\textrm{m}^3$ without regard to combined aggregates. 3) The effect of S/a on high fluid concrete by combined aggregates is approximately S/a 50% (type A and B), s/a 50-55% (type C). 4) Consistency measuring of high fluid concrete by K-slump tester is possible and first indication value, high fluid concrete can be produced, is 6~10.5cm.

• 콘크리트학회논문집
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• 제25권1호
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• pp.3-9
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• 2013

초고강도 콘크리트에서 잔골재로 세척사 대신에 전기로 산화 슬래그를 사용했을 경우, 재령 91일 압축강도가 약 15 MPa 정도 향상되었다. 압축강도가 향상된 원인을 규명하기 위해 잔골재의 Ca 성분 용출 특성을 고찰하였고, 잔골재와 페이스트 계면에서의 미세조직, 기공율, 미소경도 및 Ca/Si 몰비를 검토하였다. 그리고 잔골재 형상에 의한 강도 증진 효과를 알아보기 위해 잔골재의 표면 거칠기를 AFM으로 측정하였다. 실험 결과, 초고강도 콘크리트에서 전기로 산화 슬래그 잔골재 사용에 의한 강도 증진 기구는 화학적 기구와 물리적 기구로 구분할 수 있다. 화학적 기구로는, 전기로 산화 슬래그에서 함유되어 있는 가용성 Ca 성분이 용출되어 잔골재와 페이스트 사이에 반응생성물을 형성시켜 조직을 치밀화 시킴으로 잔골재-페이스트간의 부착력을 증진 시키는 것으로 나타났다. 그리고 물리적 기구로는, 전기로 산화 슬래그 잔골재는 세척사에 비해 표면의 굴곡도가 2배 정도 커서, 잔골재와 페이스트 간의 interlocking strength를 증가시킴으로서 압축강도 발현에 기여하는 것으로 판단했다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.71-72
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• 2015

As this study is the one related to the ultra high strength concrete essentially used for high rise buildings, it has analyzed on the flowability of ultra high strength concrete according to the variation of coarse aggregate and fine aggregate. The coarse aggregate was planned as two types including Granite Aggregate (GA) and crushed coarse Limestone Aggregate (LA) while fine aggregate was planned as four types including Sea Sand (SS), Limestone Crushed Fine Aggregates (LFA), Electric Arc Furnace Oxidizing Slag Aggregates (EFA) and Crushed Sand (CS) to perform experiment with a total of eight variables. As a result of analyzing slump flow, 500mm concentration time, U-Box and L-Flow, etc. among the characteristics of fresh concrete, a mix using LA+LFA is determined to show high flowability in case of applying ultra high strength concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.107-110
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• 1999

The objective of this study is to obtain characteristics of early age pore-structure and carbonation of concrete using ground granulated blast furnace slag (GGBFS). The durability of GGBFS concrete should be evaluated for wide use of the GGBFS. As for that evaluation, an analysis on early age pore-structure characteristics of GGBFS concrete are very important, Carbonation depths of GGBFS concrete, which are known to be larger than that of OPC, are different according to replacement ratios and fineness of slag. Because sea sand as fine aggregate is much used recently, it is also necessary to analyze characteristics of carbonation of GGBFS concrete. In this study, The micro-pore structure formation characteristics of GGBFS concrete are obtained through the test of GGBFS mortars with different fineness and replacement ratio of GGBFS. The carbonation of GGBFS concrete is also investigated by acclerated carbonation test for early age GGBFS concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 추계 학술논문 발표대회
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• pp.29-32
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• 2005

Recently, for the problem solution of demand and supply imbalance of fine aggregate due to the shortage of natural fine aggregate and the environment regulation on sea sand extraction in the construction field, the studies for the application of recycled fine aggregate using waste concrete are being progressed versatilely. The purpose of this study is to investigate quality of recycled fine aggregate manufactured by drying manufacturing system which is the manufacture method of high duality recycled fine aggregate, and to analyze on thehardened and durability properties of recycled concrete using it. Therefore it is to present the fundamental data for application and utilization of recycled concrete. The results of this study are as follows; Quality of recycled fine aggregate by drying manufacturing system is improved, and compressive strength, carbonation depth and chloride ion penetration depth of recycled concrete using high quality recycled fine aggregate are similar to those of normal concrete using natural and crashed sand. But, resistance to $H_{2}SO_{4}$ show decreased somewhat.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.389-392
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• 2008

철강 산업에서 발생되는 슬래그 부산물 중 전기로슬래그는 슬래그 자체의 팽창반응성으로 인해 콘크리트용 원자재로서 활용이 불가능하지만, 슬래그의 팽창반응성을 제거한 전기로산화슬래그는 콘크리트용 골재로서 활용이 가능하다. 본 연구에서는 산화 전기로슬래그 잔골재를 사용한 콘크리트의 기초품질 특성을 검토한 것으로서, 산화 전기로슬래그 잔골재는 입형이 둥근 풍쇄전기로슬래그 및 입형이 부순모래와 유사한 파쇄 전기로슬래그 잔골재가 있으며, 본 실험에서는 파쇄 전기로슬래그 잔골재를 사용하였다. 잔골재에 대해 용적 대체한 경우에서의 콘크리트의 품질 특성을 검토 결과, 전기로슬래그 잔골재는 골재 자체의 밀도가 일반 천연골재에 비해 매우 높고, 흡수율이 매우 낮기 때문에 전기로슬래그 잔골재 대체율이 증가할수록 동일 유동성을 확보하는 단위수량은 감소하는 경향을 나타내고 있으며, 동일 단위수량 적용시에도 콘크리트의 강도 발현 특성은 증가하는 경향을 나타내고 있다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.759-762
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• 1999

The concrete structures possessing good structural integrity can face durability problems due to deteriorations of concrete structures under various environmental conditions. The durability problems weaken the structural integrity in the long run. Especially, the excessive use of sea sand causes serious reinforcement corrosion and carbonation in concrete structures. An accelerated test is often used to predict deterioration as a qualitative measure, but without long term exposure test results or understanding of the relationship between the accelerated test and the long term exposure test, the accelerated test result alone can not be used effectively as a quantitative measure. In this paper, a methodology is proposed to predict the long term deteriorations, based on the result of the short-term accelerated test, of concrete containing different contents of chloride ions. Then, the correlation between two results on the steel corrosion ratio and the carbonation depth is analyzed for concrete with different chloride contents.

• 한국건설순환자원학회논문집
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• 제5권3호
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• pp.247-252
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• 2017

본 연구는 Reject Ash(Rj)를 혼합골재에 프리믹스하여 활용함에 따르는 가능성을 분석한 것이다. 즉, 서로 다른 입자특성의 저품질 잔골재인 석산 B+해사(CSb+SS), 발파석+해사(BS+SS)의 혼합골재에 대한 Rj의 치환율 변화에 따른 시멘트 모르타르의 기초적 특성을 파악하고자 하였다. 실험결과, 먼저 플로는 CSb+SS의 경우 Rj의 치환율이 증가함에 따라 거의 변화가 없었으며, 공기량은 CSb+SS와 BS+SS의 경우 모두 Rj의 치환율이 증가함에 따라 감소하는 것으로 나타났다. 압축강도는 CSb+SS와 BS+SS의 경우 모두 Rj의 치환율이 증가함에 따라 증가하는 것으로 나타났다. 따라서 혼합골재에 Rj를 5% 정도 치환할 경우에 품질이 양호한 골재를 사용한 경우와 유사한 것으로 판단되며, 5% 이상 치환할 경우에도 콘크리트의 유동성 확보 및 강도증진에 긍정적으로 기여하게 됨을 확인할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.600-603
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• 2004

Recently, the river sands are in short supply. Gathering sea-sand will be faced with difficulty. Alternative aggregates for concrete are estimated by many researchers. The aggregates are blast furnace slag, steel slag, copper slag, ferro-nickel slag and recycled aggregate and etc. Nevertheless steel slag has been limited in practical use due to its expansibility which is occurred reaction with water and free CaO in slag. Most recently stable management method is to minimize the expansibility researched and developed. First of all, slump, air content, compressive strength and flexural strength are measured in concrete. An estimate is made of the segregation of concrete containing atomized steel slag by Image Analyser program.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.177-180
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• 2006

Reinforced concrete has been widely used as a semi-permanent construction materials. However, sea sand, deicing salt, and marine condition might induce the corrosion of embedded reinforcement due to the penetration of chlorides in concrete structures. This reinforcement corrosion causes serious problems on safety and serviceability of structures during lifetime. Also, reinforcement corrosion may cause the collapse of structures in worst case, so that the corrosion problem is more and more intensely growing. The purpose of this paper is to provide the fundamental data for the mechanical effect of corrosion through evaluation on bond characteristics of reinforced concrete using corroded bars.