• Cement
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• s.173
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• pp.78-83
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• 2006

국내 건설산업의 축소에 따라 수요가 감소하고, 외국산 시멘트의 수입량이 증가하며, 시멘트 콘크리트가 환경문제와 연관이 있다는 인식이 확산되는 등 위기에 직면해 있는 국내 시멘트 산업은 재도약을 위하여 노력하고 있다. 한국양회공업협회, 산업자원부, 건설교통부 등의 후원으로 한국콘크리트학회에서 이러한 시멘트 및 콘크리트 관련산업의 환경 및 품질과 관련한 당면과제를 극복하고, 선진외국의 사례를 참고하여 국내 시멘트, 레미콘 등 콘크리트 관련산업의 경쟁력 제고를 도모하고자 지난 2006년 11월 17일(금)에 한양대학교 백남학술정보관 국제회의실에서 "환경과 콘크리트"를 주제로 시멘트 및 콘크리트 산업 경쟁력 향상을 위한 국제 심포지엄을 개최하였다. 이번 국제 심포지엄은 최근 산업폐기물을 시멘트 제조원료로 사용하는 것과 관련, 많은 논란이 일어나고 있는 가운데, 최근 언론보도에서는 다소 간과된 지구환경 보전측면에서 시멘트 콘크리트 산업이 공헌하는 측면에 대해서 활발한 주제 발표가 있어, 많은 주목을 받았다. 먼저, 외국연사로서 초청된 미국 시멘트협회(Portland Cement Association)의 Thomas B. Carter 부회장은 시멘트 산업이 반환경적인 측면으로 비추어지는 부분을 최소화할 수 있는 다양한 방안을 제시하였고, 일본 태평양시멘트 중앙연구소의 토미타 로쿠로 소장은 일본에서의 산업폐기물 사용 현황 및 다양한 산업폐기물 재활용 기술을 소개하였다. 특히, 일본에서 생산된 시멘트 1톤에 활용되는 폐재료 및 부산물의 양이 평균 400kg에 이르고, 생활쓰레기를 사용한 Eco-Cement의 생산현황 및 지방자치단체의 협조체제 등을 볼 때, 자연환경을 훼손하는 일부 부정적인 이미지만 부각되어 환경파괴의 주범으로까지 잘못 인식되고 있는 우리 현실과 극명하게 대비되어 눈길을 끌었다. 이어서 국내 연사로 나선 군산대학교 이승헌 교수는 "최근 일각에서 제기하고 있는 시멘트중의 미량성분으로 포함돼 있는 6가 크롬에 대한 유해성 여부에 대해 문제제기 차원에서는 바람직하나 시멘트를 유해물질이라고 단정짓는 감성적인 접근보다는 좀더 다양한 실험을 통해 이의 유해성 여부를 규명짓는 것이 선결되어야 한다" 고 언급하였다. 이에 심포지 엄에서 많은 관심을 불러일으킨 토미타로쿠로 일본 태평양시멘트 연구소장의 연구논문과 이승헌 교수의 연구논문을 중심으로 심포지엄의 성과를 간략하게 소개하고 시멘트 콘크리트 관련 전문가가 참석한 종합토론을 정리, 요약 게재한다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.389-394
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• 2017

The aim of the research is providing the application method of recycled materials to manufacture the low costed eco-friend block at currently operated concrete block plant. In this research, based on the previous research results on three types of slag cement with illite, desulfurized gypsum, and wasted refractory products, the actual block product was manufactured by the currently operated plant facility and evaluated their properties to suggest the optimal proportions. As an experimental results, in aspect of compressive strength, absorption ratio, freezing resistance, and pH, type III slag incorporating 5% desulfurized gypsum with 1% replaced illite as an aggregate could be suggested as am optimal proportion. In additionally, considering the high cost of the illite, it can be considered as an optimal proportion that type III slag incorporating 5% desulfurized gypsum for binder.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.345-352
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• 2017

Heavy weight concrete can be used in marine concrete structure to improve resistance against high wave energy. However, heavy weight aggregate, which is an indispensable material for heavy weight concrete, is difficult to be supplied in large quantities because its use is limited due to its high cost. In this work, the applicability of heavy weight by-products, copper and 3 month aged steelmaking slags, were evaluated as sources of heavy weight aggregate for marine concrete structures. Experimental results showed that copper slag was found to be a stable material for marine concrete structure. However, 3 month aged steelmaking slag showed significant expansion by $80^{\circ}$ water immersion test and ASTM C 1260 test. In addition, depth of chloride ion penetration in concrete was higher at which steelmaking slags were located. It was associated with porosity of steelmaking slag, and for this reason, steelmaking slag was not found to be suitable for marine concrete structure.

• 수도
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• v.24 no.4 s.85
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• pp.30-38
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• 1997

County는 비용과 부지소요는 최소화하면서도 증가하는 지역적 물수요에 부합되는 높은 유량에서 정수장의 성능을 최대화해야하는 필요성에 직면해있다. 개선사항을 찾아내기 위하여 시설물에 대한 상세한 성능평가가 행해졌다. 성능평가는 여과와 소독공정이 운전방식의 조정과 함께 추가시설의 건설에 의하여 개선될 수 있음을 나타내었다. Pilot test는 실험된 여러 가지 대안들 중에서 혼화, 응집, 이중 여과방식이 입자의 제거와 정수 수질에 가장 좋은 것임을 보여주었다. 소독에 대한 분석 결과는 소독방법을 교정하고 추가적인 염소접촉시간을 주는 것이 소독의 안전성을 확보함과 동시에 정수의 소독부산물 농도를 최소한으로 하고 강화되는 규제치와 부합할 수 있는 최선의 방법이 될 것이라는 것을 보이고 있다. Pilot test는 저수두 자동역세척여과지가 1차여과지(roughing filter)로서 효과적이라는 것을 보여주었다. 실험결과는 이중여과가 최종유출수의 탁도를 평균 0.1NTU이하로 감소시키며 입자의 제거율을 3 log로 증가시킴을 나타내고 있다. 정수공정 전반에서의 입자의 제거는 여러 개의 공정의 개별적 성과의 합이 아니므로 시설물들을 건설하기 전에 정수장 전체적으로 예상되는 개선정도를 수량화하기 위하여 Pilot 실험이 필요하였다. Pilot test중에 탁도보다는 입자측정이 유량, 응집제의 주입량, 및 여타 운전조건의 변화에 훨씬 민감함을 보여주었다. 이러한 점이 입자측정이 특히 저탁도 원수에서 처리공정의 성능을 나타내 주는 적절한 추가적 수질인자라는 결론을 보강하여 주었다. 물수요에 부합하기 위하여 Freedom District 정수장을 성공적으로 개선하는 데는 원수의 수질, 단위공정의 성능, 활용가능한 수리학적 수두, 현시설의 배치, 운전양태 등과 같은 기술적 사항에 대한 고려가 필요하였다. 비록 모든 사항들이 각각 일정정도의 영향을 가지고 있으나, 상기의 모든 것들이 수질에 영향을 미쳤으며 수질의 성공적인 개선은 정수장 운전의 모든 부분을 파악할 수 있는 상세한 성능평가를 통하여 가장 잘 달성될 수 있다.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.134-138
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• 2003

The purpose of this paper is to recycle the fly ash to the valuable resources and settle environment problems which was caused by the fly ash produced from the thermal power plant. Making the fly ash-cement matrix reused fly ash in large quantities, we looked into minutely the physical properties - the elastic modulus, the compressive strength - to increase the usefulness as the building materials for the structure widely. In this paper, the variables are the water-binder(39, 42, 45%), the fine aggregate ratio(37, 41, 45%). Because the fracture energy is influenced by the strength, it is showed to decrease with the increase of W/B and S/a. Besides, we will be able to know that basic properties of the fly ash-cement matrix are similar to that of concrete. But, it is needed to carry out durability experiment on the drying shrinkage, creep, freezing and thawing test to use structural materials.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.623-629
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• 2002

Porous concrete enables water and air to pass through a firmly hardened material and allows required nutrients to reach roots of plants. The purpose of this study is to analyze void ratio, strength property and planting ability when using silica fume and fly ash, the change of aggregate gradation and ratio of paste to aggregate. The results of an experiment from the planting ability of the porous concrete to its influence on the compressive strength are reported in this paper. As a result of the experiment, the compressive strength is higher when the gradation of aggregate is smaller, and it also goes higher when the ratio of paste to aggregate gets larger. The planting ability of porous concrete is decided by the germination and the grass length of perennial ryegrass. The grass length of perennial ryegrass is longer when the gradation of aggregate is greater and the ratio of paste to aggregate gets smaller. Therefore the efficiency of planting goes through the perennial ryegrass is in compliance with the void ratio, aggregate gradation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.80-87
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• 2011

Blast furnance slag cement is a cement manufactured with using industrial by-product and it can reduce $CO_2$ by replacing cement when same uit volume concrete is produced. But Blast furnance slag has a short point that early strength of concrete is not good in winter season and it can be used. So, in this study, as long as replacement ratio of Blast furnance slag to original portland cement is under 30%, developed cement, ecoment, improve early strength of concrete and it applied to constructoin site. As a result, it improves 37% in terms of 1-day strength, it reduces 6.7% in terms of $CO_2$ emission when $1m^3$ concrete was produced. The importance and applicability of study wll be expected to increase cosidering global effort and green growth-strategy in country for reducing greenhouse gases.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.356-362
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• 2016

Light-weight concrete uses forming agents for reducing weight and high heat insulation property. However, the forming agents make problems of decreased volume and compressive strength of the concrete. This research aims to having weight-reduction and securing heat insulation property using recycled wasted form polyurethane without any forming agents. A small quantity of admixture used for constructability and avoiding material segregation. We picked admixtures from two different companies which shows evenly dispersed of wasted form polyurethane. This research conducts a study on the effect of mixing ratio of admixture on the light-weight concrete used wasted form polyurethane. As a result of the test, increased mixing ratio of the admixtures results reduced fluidity of concrete. On the other hand, percentage of moisture content and compressive strength are increased slightly. Combustibility performance and sound insulation performance are also secured, as well.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.841-844
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• 2008

Non-refining fly ash and bottom ash, the byproducts generated from the coal-fired power stations, have usually been disposed of in onshore ash disposal sites. With an increase of power consumption due to industrial development, the generation of coal ash has been growing tremendously. Current insufficiency of disposal sites and environmental concerns over newly-built disposal sites have also led a growing need to utilize the coal ash. Accordingly, this paper compares and analyzes the fundamental properties of the coal ash collected from each disposal sites in order to increase the usability of the coal ash generated from coal-fired power stations. The results of the study indicate that coal ash shall be separately applied by the properties for each intended use as the ash greatly differs in its properties depending on the site of disposal. In particular, it is shown that the overall evaluation on the ash shall be necessary as the quality might be varied by the change of absorptance when applied as an aggregate for concrete. From the examination on the salt content, it has been observed that the ash can be applied as an aggregate for concrete only after more than 3 times of washing process.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.413-422
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• 2019

A ferrosilicon (FS) by-product was applied into a cementitious binder in concrete substituting the ordinary Portland cement (OPC). The original material characteristic of FS is very identical to silica fume (SF) regarding chemical composition and physical properties such as specific surface area and specific gravity. Therefore, the FS and SF concrete or mortal of which 10% of the material was replaced to total binder weight were fabricated to evaluate the feasibility of using F S as a binder, and the comparative information of OPC, FS and SF concrete was given. The hydration characteristic of FS concrete was analyzed using X-ray diffraction analysis. The FS concrete was beneficial in compressive strength, resistivity against chloride ingress and reducing porosity considering performance of OPC concrete but the advantage was less than using SF. A possibility of alkali-silica expansion was found out from the FS concrete due to the agglomerated size of the silica particles.