• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.146-147
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• 2014

In this study, as the resistance of the carbonation for high volume admixture incorporating concrete, coating effect of using refined cooking oil in the surface of high volume admixture incorporating concrete has been tested. The following results could be made as the conclusion. For the fresh concrete, the slump and air content has been identified as satisfying the target range. For the hardened concrete, comparing with specimen of Plain, specimen with coating showed better long age compressive strength. For the carbonation speed, the specimen of FA30 showed highest speed and the specimen of BS60 showed higher speed than specimen of Plain. For all the specimens coated with RCO, as the decrease of capillary pores inside the concrete, the carbonation speed has been obviously decreased and with even better effect than using PEP coating. It could be identified that specimens with coating by RCO showed good effect on refrain the speed of carbonation.

• 콘크리트학회지
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• 제9권1호
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• pp.165-172
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• 1997

경량기포콘크리트란 시멘트슬러리 속에 미리 생성된 기포를 혼합시켜 양생시킴으로써 동일한 체적의 보통콘크리트보다 가볍게 만든 콘크리트를 의미한다. 본 연구의 목적은 고분자기포제를 이용하여 초경량성과 타설에 충분한 유동성을 확보하면서 소요강도를 갖는 최적의 선기포방식의 경량기포콘크리트를 개발하는데 있다. 연구결과 실리카흄, 플라이애쉬 등의 혼화재와 산업부산물인 발포포리스티렌비드의 혼합으로 경량기포콘크리트의 역학적 특성을 개선시켜 기존의 선기포방식으로 제조된 경량기포콘크리트보다 유동성 , 경량성과 강도특성이 우수한 경량기포콘크리트를 개발하였다. 본 논문에서는 개발된 경량기포콘크리트의 여러 가지 배합인자에 따른 유동성 및 압축강도를 규명하였으며 최적 배합비를 도출하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.1113-1116
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• 2008

실리카퓸, 플라이애쉬, 고로슬래등 미분말 혼화재가 포함된 고성능 콘크리트(High Performance Concrete) 교량 바닥판 보호공법은 1980년 초부터 북미를 중심으로 사용되어 왔다. 본 보고서에서는 교량 바닥판 보호를 위한 고성능 콘크리트 적용사례와 고성능 콘크리트를 이용한 두 가지 공법(고성능 콘크리트 교면포장공법, 노출 바닥판 공법)에 대해 소개한다. 위 두 공법은 이미 북미에서 많은 실적을 보유하고 있으며 특히, 실리카퓸과 PVA섬유가 포함된 고성능 콘크리트 교면포장공법은 국내에서도 성공적으로 적용되고 있다. 따라서 본고에서는 기존 아스팔트 재료를 대체할 수 있고, 최근 국내에서도 그 적용성에 대한 관심과 실 시공이 이루어지고 있는 고성능 콘크리트를 이용한 교면포장 (Overlay) 공법 및 노출 바닥판(Full depth) 공법에 대해 소개하고자 한다.

• KCI Concrete Journal
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• 제11권3호
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• pp.89-97
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• 1999

The purpose of this research is to investigate the utilization of recycled fine aggregates as a material to apply to a building finished walls or as a decorating material in combination with a polymer. The strengths of two resin mortars using recycled fine aggregates and natural fine aggregates was made. In order to improve the workability and the strength of the resin mortar with recycled fine aggregates, partial replacement of recycled fine aggregates with natural ones was made with the application of various type of fillers. The results, it show that the compressive strength and flexural strength of resin mortar using the recycled fine aggregates were about 70% to 100% of those of resin mortar using natural fine aggregates. It was enough to assure the utilization of the recycled fine aggregates as a material for the production of resin mortar. From the result of partial replacement of recycled fine aggregates with natural ones, the compressive strength was Increased from 5% to 15% and the flexural strength was much as 5% to 20% as a result of 70% substitution It was also found that the use of garnet powder shows a similar tendency in the compressive strength and slag powder does in the flexural strength and tensile strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.485-488
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• 2006

This research has evaluated flowability of ultra flowing self-compacting concrete, which is limitedly used for traditional building structures, in accordance with the first class regulations of Japan Society of Civil Engineering(JSCE) that can be applied to overcrowding-arrangement of bar, as a part of application methods that ultra flowing self-compacting concrete is applied to both precast and prestress bridge structures. The experimental results show that the flowability is acceptable in ternary blended among binary and ternary blended mixings, which satifies the first class regulation of JSCE. It is also concluded to use fly ash to increase viscosity of concrete in the case of segregation resistance because of low viscosity in the mixture of slag from blast furnace and limestone micropowder. Satisfying goals of every mixing after U-box self-compacting experiment, we conclude that ultra flowing self-compacting concrete is applicable to bridges and civil constructions of overcrowding arrangement of bar with evaluation of flowability of ultra flowing self-compacting concrete.

• 한국구조물진단유지관리공학회 논문집
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• 제2권4호
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• pp.186-193
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• 1998

The purpose of this research is to seek properties of flowing light-weight aggregate concrete and possibility of application. The experimental analysis results by using light-weight aggregate and industrial waste such flyash, furnace slag are as follow. 1) The research shows that flowing light-weight aggregate concrete of slump 23~27cm, slump flow 58~69 cm is possible, but material segregation is appeared above slump 26.5cm and slump flow 65 cm. 2) If mixing ratio of flyash is increase, strength deterioration is about 25 % in early age. It showed that effectiveness of long time strength improvement because strength manifestation ratio is above 95% in a long term. 3) This research showed possibility of substitution of blast furnace slag because strength deterioration by using mixing of furnace slag was appeared small deterioration range as below 10 %. 4) Each experimental compressive strength ratios were 77 %(1st week), 86 %(2nd week), 109 %(8th week), 115 %(13th week), 125 % (26th week) on the basis of 28 days. If mixing ratio of flyash is increase, long term strength increase ratio is improved.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.259-263
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• 2001

There are several steps such as slicing, lapping, chemical etching and mechanical polishing in the silicon wafer production process. The chemical etching step is necessary to remove damaged layer caused In the slicing and lapping steps. The typical etching liquor is the acid mixture comprising nitric acid, acetic acid and hydrofluoric acid. At present, the waste acid is treated by a neutralization method with a high alkali cost and balky solid residue. A solvent extraction method is applicable to separate and recover each acid. Acetic acid is first separated from the waste liquor using 2-ethlyhexyl alcohols as an extractant. Then, nitric acid is recovered using TBP(Tri-butyl phosphate) as an extractant. Finally hydrofluoric acid is separated with the TBP solvent extraction. The expected recovered acids in this process are 2㏖/l acetic acid, 6㏖/1 nitric acid and 6㏖/l hydrofluoric acid. The yields of this process are almost 100% for acetic acid and nitric acid. On the other hand, it is important to recover and reuse the metal values contained in various industrial wastes in a viewpoint of environmental preservation. Most of industrial products are made through the processes to separate impurities in raw materials, solid and liquid wastes being necessarily discharged as industrial wastes. Chemical methods such as solvent extraction, ion exchange and membrane, and physical methods such as heavy media separation, magnetic separation and electrostatic separation are considered as the methods for separation and recovery of the metal values from the wastes. Some examples of the application of solvent extraction to the treatment of wastes such as Ni-Co alloy scrap, Sm-Co alloy scrap, fly ash and flue dust, and liquid wastes such as plating solution, the rinse solution, etching solution and pickling solution are introduced.

• 한국도로학회논문집
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• 제14권3호
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• pp.1-7
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• 2012

본 논문에서는 ASTM C 1260을 이용하여 국내산 골재를 대상으로 알칼리-실리카 반응 판정 결과 반응성으로 판정된 골재를 대상으로 알칼리-실리카 반응 억제효과를 고찰하기 위하여 플라이애시와 질산리튬을 사용한 시멘트 경화체의 ASTM C 1260 적용성을 평가하였다. 알칼리-실리카 반응에 의한 팽창현상이 발생하는 지역에서 CaO 함량이 낮은 플라이애시를 시멘트 중량의 10, 20, 30%를 대체하는 경우 ASTM C 1260으로 알칼리-실리카 반응 억제효과를 확인할 수 있었다. 그러나 질산리튬을 사용할 경우는 ASTM C 1260은 시편을 1N NaOH 수용액에 수침하여 $80^{\circ}C$의 온도로 길이변화를 유도하므로 시편내에 혼입된 질산리튬 성분이 외부로 용출될 수 있기 때문에 알칼리-실리카 반응 억제효과를 도출하지 못하였다. 따라서 질산리듐의 ASR 억제효과를 확인하기 위해서는 다른 시험방법을 고려해야 한다.

• 대한토목학회논문집
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• 제28권1A호
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• pp.155-163
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• 2008

최근 구조물이 대형화, 특수화 및 초고층화 되고 있는 건설현장에서는 일반콘크리트보다 더 뛰어난 고성능 콘크리트의 시험적인 시공이 증가하고 있는 추세이다. 교량의 경우 과거 동바리 공법에 의한 시공은 소음 및 분진과 공사기간의 장기화 등의 문제로 점점 감소되었으며, 최근에는 시공기간 단축 및 도심지 환경에 적합한 프리캐스트로 시공하는 현장이 급속히 증가하고 있다. 교량구조물의 경우 휨에 대한 안전성을 확보하기 위하여 과밀배근된 부재를 생산하고 있는 실정이며, 과밀배근된 부재를 생산하기 위하여 일반콘크리트보다 유동과 충전성능이 월등한 초유동 자기충전 콘크리트가 적용되는 것이 바람직하다고 판단된다. 본 연구에서는 고로슬래그 및 플라이애쉬를 2성분계 및 3성분계 배합을 통하여 과밀배근된 교량구조물에 초유동 자기충전 콘크리트를 적용하기 위한 방법으로 과밀배근된 구조물에 적용할 수 있는 일본 토목학회의 JSCE 1등급 규정에 따른 초유동 자기충전 콘크리트의 유동 특성을 검토하였다.

• Computers and Concrete
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• 제22권4호
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• pp.407-417
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• 2018

Over the past three decades, self-compacting concrete (SCC), which is characterized by its superior rheological properties, has been gradually used in construction industry. It is now recognized that the application of SCC using supplementary cementitious materials (SCM) is highly attractive and promising technology reducing the environmental impact of the construction industry and reducing the higher materials costs. This paper presents an experimental study that investigated the mechanical and durability properties of SCCs manufactured with blended binders including fly ash, slag, and micro-silica. A total of 8 batches of SCCs were manufactured. As series of tests were conducted to establish the rheological properties, compressive strength, and durability properties including the water absorption, water permeability, rapid chloride permeability and initial surface absorption of the SCCs. The influences of the SCC strength grade, blended types and content on the properties of the SCCs are investigated. Unified reactive indices are proposed based on the mix proportion and the chemical composition of the corresponding binders are used to assess the compressive strength and strength development of the SCCs. The results also indicate the differences in the underlying mechanisms to drive the durability properties of the SCC at the different strength grades.