• 자원환경지질
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• 제30권2호
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• pp.175-183
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• 1997

The concrete structure can be easily damaged due to alkali-aggregates reaction. There are several methods to identify alkali reactivity of aggregates. The most reliable method is mortar-bar test, but it takes 3 to 12 months for whole test. The authors applied "rapid method" which takes only 7 days for this test. The result of this rapid method follows; expansion ratio of mortar bar for natural aggregates taken at the Youngsan River ranges from 0.197 to 0.489%, but that from Changseong Lake has low expansion ratio of 0.147%, which is below the limit of allowance, 0.168%. Those from the Seomjin River range from 0.173 to 0.22%, and those from the Keum River range from 0.078% to 0.111%. In the case of higher expansion ratio than 0.168%, aggregates must be used with cement containing low alkali content or adding material consuming the alkali content of cement, for example, fly ash and silica fume, etc.. Most of natural aggregates in Cheolla area have no problem in physical properties, particularly the abrasion ratio is below 40%, the limit of allowance. The natural aggregate from Cheolla area consists mostly of gneiss, granite and volcanic rocks. The major alkali reactive materials are quartz mineral with undulatory extinction in gneiss and granite, and amorphous silica in volcanic rocks. Even if a certain aggregate consists of the same kind of rocks and has similar rock composition each other, content of alkali reactivity material can be various, because rock formation is locally different according to temperature and pressure. Therefore every rock type must be physically and chemically identified before using for aggregates.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.549-554
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• 2001

It is possible for concrete using sea sand to contain chloride ion as well as cation such as Na$^{+}$and $K^{+}$ during mixing process. It is known that some cations such as Na$^{+}$and $K^{+}$ remain in pore solution without binding In this study, therefore, we intend to inspect the behavior of cations in cement paste as well as NaCl, CaCl$_2$ and KCI through analysis of pore solution extracted from cement paste with high pressure vessel. As a result, increase of alkali ions by adding sea sand and admixtures to the fresh concrete means use of the cement contained high alkali contents. In this case, alkali ions in pore solution can decrease durability of cement products causing alkali-aggregate reaction or accelerated carbonation. So it needs to be studied.studied.

• 콘크리트학회논문집
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• 제20권4호
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• pp.431-437
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• 2008

한국에서는 그동안 콘크리트구조물에서 알칼리-실리카 반응에 의한 피해 사례가 학계에 보고된 바가 거의 없는 상태이다. 최근 일부 고속도로 콘크리트 포장에서 알칼리-실리카 반응에 의한 균열과 스펄링 발생하였다. 본 연구에서는 최근 몇몇 국가에서 콘크리트용 골재의 알칼리-실리카 반응성을 조기에 판정하는데 효과가 있는 ASTM C 1260 촉진 모르타르 봉 방법으로 한국산 암석에 대하여 재령별 팽창 특성을 분석하고자 하였다. 실험 결과 한국산 골재 중 화성암 골재 10종 중에서 14일 재령에 0.1% 이상의 팽창이 발생한 골재는 복운모 화강암, 규장암이 반응성이 있는 것으로 실험되었다. 퇴적암 골재 5종 중에서는 14일 재령에 0.1% 이상의 팽창이 발생한 골재에는 장석사암, 적색사암, 셰일로서 잠재적인 알칼리-실리카 반응성이 있는 것으로 실험되었다. 변성암 골재 11종 중에서 14일 재령에 0.1% 이상의 팽창이 발생한 골재에는 충남 보령 점판암으로서 0.303%의 팽창이 발생하여 반응성이 매우 큰 골재임을 알 수 있었다. 이와 같이 한국산 골재에서도 알칼리-실리카 반응에 의한 팽창 현상이 크게 발생함을 알 수 있었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.21-22
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• 2021

This study incorporates fine waste glass (GS) as a replacement for natural sand (NS) in ground granulated blast furnace slag (GGBS) based alkali activated mortar (AAm). Tests were conducted on the AAm to determine the mechanical properties, apparent porosity and the durability based on its resistance to Na2SO4 5% and H2SO4 2% concentrated solutions. The study revealed that increasing GS up to 100 wt%, increased strength and decreased porosity. The lower porosity attained with the incorporation of GS, improved the resistance of mortar to Na2SO4 and thus increasing durability. However, the durability of mortar to H2SO4 solution was negatively impacted with the further reduction of porosity observed with increasing GS above 50 wt.% believed to be caused by the stress induced as a result of expansive reaction products created when the mortar reacted with acid.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 가을 학술발표회 논문집
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• pp.447-450
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• 1994

The chemical method and mortar-bar method for identification of the susceptibility to Alkali-Aggregate Reaction (AAR) was established as KS method by referencing the ASTM methods. However, the chemical method requires skilled chemical engineers and aggregates are tested in very severe condition, and on the other hand, the mortar-bar method needs a long time of 3 or 6 months. Judging from this circumstance that the use of crushed stones are increased due to the shortage of natural aggregates, the development and standardization of a new rapid test method is considered essential. The purpose of this paper is to research for the possibility to apply the rapid method, instead of the chemical method and the mortar-bar method with using the several domestic crushed stones.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.541-544
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• 2006

This study was performed to proof expansion effect of the mortar bar due to Alkali-silica Reaction (ASR) by ASTM C 1260 test. Recently, the failure case of cement concrete pavement by ASR was reported in Korea. Cement concrete structures are caused crack by ASR. The service life of cracked cement concrete structures by ASR will be shorted. In this study, crushed the slate rock producted Chungcheongnamdo Boryeong was caused 0.3% expansion at 14 days due to ASR by ASTM C 1260 test. The particular spectrum showed that the ASR gel was analyzed contents included Si, Na, K, and Ca by EDX (electron dispersive X-ray spectrometer). It was verified that the crushed aggregate was caused expansion by ASR in Korea.

• 콘크리트학회지
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• 제9권1호
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• pp.115-121
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• 1997

본 연구는 NaCl 수용액 중에서 고로 슬래그미분말의 알칼리실리카반응에 대한 팽창억제 특성 및 그의 메카니즘에 관한 것이다. 실험에 사용된 NaCl 수용액의 농도는 0%(수도수), 2.8% 및 20%였으며, 골재는 안산암을 사용하였다. 슬래그는 비표면적이 $4,100cm^2/g.\;5,960cm^2/g$ 및 $7,950cm^2/g$인 3종류를 사용하였고 치환율은 시멘트중량에 대하여 40%, 60%, 70% 및 80%로 하였다. NaCl 수용액에 있어서 슬래그를 첨가한 공시체는 치환율이 많을수록 수축률은 높게 되었고 그의 값은 비표면적이 클수록 높게 나타났다. 슬래그에 의한 알카리실리카반응의 유해한 팽창의 억제는 슬래그의 첨가에 의한 경화 콘크리트의 화학적 수축에 의해서도 달성됨이 확인되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.337-338
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• 2013

Recent research is needed for the reduction of the pH of the recycled aggregates, recycled aggregates for alkali social problems have emerged. This was confirmed through preliminary experiments using a self-made reactor with dry ice, the possibility of reducing the pH of the recycled aggregates. The pH reduction of coarse recycled aggregates plant was made to apply the field to the middle of construction waste treatment process to reduce the pH of the plant room, and measured the pH change with time. The measurement results showed that dry ice after the reaction, the pH of the aggregate 5% reduction than untreated recycled aggregates.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.34-35
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• 2015

The purpose of this study is to investigate the compressive strength property of concrete with Ground granulated blast furnace slag(GBFS) using wash water from recycled aggregate. When GBFS is reacted with water, it doesn't happen to hydraulic reaction but GBFS becomes latent hydraulic property in alkaline environment. For this reason, if it is possible to use wash water from recycled coarse aggregate as mixture water, GBFS have the advantage of early strength due to effect of activation. We investigated the compressive strength properties of GBFS concrete using wash water from recycled aggregate. According to the experimentation result, ICP-OES showed wash water from recycled coarse aggregate has a high alkali value of pH of 12. Also, compressive strength in early age using wash water can be improved as an activation.

• 한국농공학회지
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• 제34권E호
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• pp.60-69
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• 1992

The research significance of the paper is to identify the major properties of synthetic lightweight concrete that are affected by ASR expansion and to determine the extent and magnitude of the loss in these properties. Emphasis is also given to the use of non-destructive testing techniques ; Such as dynamic modulus of elasticity and ultrasonic pulse velocity, to examine whether these methods could be used to identify the initiation of expansion and the internal structural damage caused by ASR.