• 한국건설순환자원학회논문집
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• 제6권3호
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• pp.61-68
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• 2011

시멘트의 강알칼리성 성분으로 인하여 파분쇄된 순환골재의 pH는 12이상을 발현한다. 이 시멘트의 강알카리성은 환경적으로 피해를 주게 된다. 순환골재의 강알카리성은 골재의 특성, 알카리 용출시간, 골재의 크기 등에 따라 다양하게 나타날 수 있다. 본 연구에서는 이러한 다양한 조건에 따른 순환골재의 pH 특성을 시험하기 위하여 습식 및 건식 생산공정에서 생산한 건식 및 습식 순환골재를 이용하여 폐기물공정 시험방법, 토양오염공정 시험방법, BS EN 1744-3에서 제시한 pH 시험방법에 따른 pH 특성, 순환골재의 용출시간에 따른 pH의 특성, 골재의 입도별 pH 특성을 분석하여 순환골재의 환경적 문제를 해결하는데 기여하고자 하였다. 시험결과에서는 순환골재는 입도가 작을수록 pH가 높은 것으로 나타났으며, 시간 경과에 따라 증가하는 것으로 나타났다. 건식과 습식 순환골재의 pH 경향은 시간 경과에 따른 차이 외에 시험방법에 의한 차이는 없었다. pH 시험방법에 있어서 폐기물공정시험에 의한 순환골재 pH값이 가장 높게 나타나 pH 편차를 고려한 단일 pH 시험방법 제안이 요구된다.

• 한국지반환경공학회 논문집
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• 제23권4호
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• pp.21-27
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• 2022

최근 GGBS 및 Fly ash 등과 같은 산업부산물과 알칼리 자극제를 활용한 알칼리 활성화 시멘트에 대한 연구가 활발히 진행되고 있다. 알칼리 활성화 시멘트는 산업부산물에 알칼리 자극제를 혼합함으로 시멘트를 사용하지 않고 강도를 발휘하는 결합재의 일종으로 대표적인 탄소저감 기술이나, 알칼리 활성화를 위해 사용되는 알칼리 자극제는 고가이며 강알칼리성으로 인한 위험성으로 현장적용에 여러 어려움이 있다. 이에 본 연구에서는 알칼리 자극제의 대체재로 Red mud의 활용방안을 모색하고자 Red mud와 제지회를 결합재로 활용한 CLSM의 유동특성, 강도특성 등의 공학적 특성과 토양오염 발생가능성을 평가하였으며, Red mud와 제지회를 혼합한 CLSM의 적정 혼합비를 제시하였다.

• Environmental Analysis Health and Toxicology
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• 제5권1_2호
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• pp.51-55
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• 1990

The ultimate Wastes generated after being treated safely and properly were land-filled in Wha Sung Treatment Plant, that of specific hazardous Wastes. There are three kinds of wastes being landfilled, which are sludges, ashes, and solidificated wastes with cement. This research scrutinizes the variations of leachate which originated from landfilled wastes amount to 30,000 ton with analizing the constituent, pH and concentration of wastes once per month since september, 1987. Now, we have some conclusions as followings; 1. The longer retention time of wastes in landfill site and the more quantity of filling-up, the closer pH of leachate to alkalinity. 2. As the quantity of copper and its compounds is over 90 percent of constituents loundfilled wastes, so the copper of leachate goes above treatment criteria. 3. There lis relationship between pH of leachate and eruption of copper and its compounds. The higher pH of leachate, the more secured copper and its compounds. So, we learn that solidificated wastes with cement is more secured than sludges and ashes. 4. The pH and concentration of copper in leachate is low in July and August, this is passing phenomenon which diluted by rainfall in rainy days. 5. The quantities of cadmium and lead of leachate was not over the treatment criteria.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.145-149
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• 2000

We performed the geotechnical experiments of the hydraulic conductivity and compressive strength test with the stabilized soil in the laboratory, proved that it is useful to use the stabilized soil as an alternative for natural clay soil. Also, for mixing adding materials in the stabilized soil, it was determined that 1) the optimal mixing ratio of cement : bentonite : stabilizing agent was 90:60:1 of mass ratio(kg) for 1㎥ with soil, 2) it was also possible to use low quality bentonite(B\circled2) classified by swelling grade because of little difference from results of the hydraulic conductivity and compressive strength test with high quality bentonite(B\circled1). According to the results of the fixation ability of heavy metals(Pb$^{2+}$, Cu$^{2+}$, Cd$^{2+}$, Zn$^{2+}$) with soil and additives, authors can conclude that the higher pH condition had the more removal efficiency of heavy metals. B\circled1 and cement had especially high removal efficiency of heavy metals in a whole pH because of high alkalinity.alinity.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.176-177
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• 2021

In order to compensate for the defects of concrete made using only Portland cement, three-component powder mixed with blast slag and fly ash, and four-component powder concrete mixed with silica fume are being produced. When each of the admixtures is used alone, the above-described excellent performance is expressed and up to 70% of the powder is used. These technologies are also contributing to the reduction of greenhouse gases under Act on Low Carbon. Green Growth. However, calcium hydroxide is consumed as a stimulator or reaction in the case of silica fume, which causes latent hydroponicity of slag, pozzolane reaction, and silica mixtures represented by fly ash. It is known that the consumption of calcium hydroxide affects the alkalinity of concrete. As a result, the carbonation resistance is significantly lower among the durability of concrete. Research on quantification of such effects is insufficient. In this study, an experiment was conducted to quantify calcium hydroxide of the three-component and four-component powder paste using thermal analysis equipment (DTG), and the effect of the mixing amount was discussed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.755-758
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• 1999

Reinforced concrete is in general known as high durability construction material under normal environments due to strong alkalinity of cement. Marine and harbour concrete in the tidal and the splash zone at seashore are exposed to cyclic wet and dry saltwaters which cause to accelerate corrosion of reinforcing steel in concrete. If corrosion resistance of concrete gets to weaken due to carbonations and cracks in cover concrete, furthermore, concrete durability rapidly decreases by corrosion of reinforcement steel embedded in concrete. The objective of this study is to develop appropriate corrosion protection systems so as to enhance the durability of concrete by controlling the cover depth of concrete and by using corrosion inhibitors as concrete admixtures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.693-696
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• 1999

Reinforced concrete is, in general, known as high durability construction material under normal environments due to strong alkalinity of cement. It is , however, well known that moderate or minor cracks in reinforced concrete should be most serious causes to deteriorate the durability of RC structures. Furthermore, chloride contents penetrating through unexpected cracks in reinforced concrete bridges get to weaken corrosion resistance of reinforcement steel in concrete and than to accelerate the deterioration of concrete durability. The objective of this experimental research is 1) to evaluate the effect of various corrosion protection system for reinforced concrete specimens with moderate or minor cracks which are exposed to cyclic wet and dry seawater, and then 2) to develop effective corrosion protection system for reinforced concrete bridges under the exposure of various detrimental environments such as seawater, deicing and etc.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.345-350
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• 2001

Reinforced concrete is, in general, known as a high durability material due to a strong alkalinity of cement. Probable concrete cracks could incur steel corrosion of RC structures and then could easily deteriorate the concrete durability, which can be fully secured by a systematic quality control for the construction of concrete structures. For the corrosion protection of reinforcing steels in concrete, however, current design specifications of concrete cover depth do not in-depth consider the effect of the cracks as well as the chloride content of RC structures. Therefore, appropriate provisions for concrete cover depth should be coded by considering the influence of concrete cracks on the corrosion of reinforcing steels. The objective of this research is to investigate pertinent cover depth, which can prohibit rebar corrosion, on the basis of experimental corrosion measurements of reinforcing steels on crack characteristics such as the width, depth and frequency of concrete cracks.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.718-723
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• 2000

Reinforced concrete is in general, known as high durability construction material under normal environments due to strong alkalinity of cement. It is, however, well known that moderate or minor cracks in reinforced concrete should be most serious causes to deteriorate the durability of RC structures. Futhermore, chloride contents penetrating through unexpected cracks in reinforced concrete bridges get to weaken corrosion resistance of reinforcement steel in concrete and then to accelerate the deterioration of concrete durability. The objective of this experimental research is 1) to evaluate the effect of various corrosion protection systems for reinforced concrete specimens with moderate or minor cracks which are exposed to cyclic wet and dry seawater, and then 2) to develop effective corrosion protection systems for reinforced concrete bridges under the exposure of various detrimental environments such as seawater, deicing and etc.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.821-826
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• 2000

Reinforced concrete is in general known as high durability construction material under normal environments due to strong alkalinity of cement. Marine concrete specimens in the tidal and the splash zone at seashore have been exposed to cyclic wet and dry saltwaters which cause to accelerate corrosion of reinforcing steel in concrete. If corrosion resistance of concrete gets to weaken de to carbonations and cracks in cover concrete, furthermore, concrete durability rapidly decreases by the corrosion of reinforcement steel embeded in concrete. The objective of this study is to develop appropriate corrosion protection systems of marine concrete so as to enhance the durability of concrete by establishing pertinent cover depth of concrete and by using corrosion inhibitors as concrete admixtures.