• Title, Summary, Keyword: 폐콘크리트

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Physical and Chemical Properties of Waste Concrete Powders Originated from the Recycling Process of Waste Concrete (폐콘크리트의 재활용 공정에서 발생되는 폐콘크리트 미립분의 물리.화학적 특성)

  • Kim, Jin Man;Kang, Cheol;Kim, Ha Suk
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.2
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    • pp.82-89
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    • 2009
  • According to the great city development and the rapid growth of redevelopment project, waste concrete emission has been increased. Waste concrete powder is one of the by-product originated from the recycling of the waste concrete. The more making high quality recycled aggregate to use aggregate for concrete, the more waste concrete powder is producted relatively. Therefore, to realize the total recycling of waste concrete, development of recycling technology for waste concrete powder need very much. This technical note present the discharged process and the various properties of waste concrete powder. As the results, on the average, the maximum particle-size of waste concrete powder is less than $600{\mu}m$, and oven-dry density is less than $2.5g/cm^3$. And waste concrete powder contains more than 50% of $SiO_2$, 30% of CaO and 10% of $Al_2O_3$. Thus qualities of waste concrete powder is lower than those of high quality raw material for concrete. However, if it is processed by grading to the purpose, it will be used as resource of raw materials for construction field.

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Optimum Mix Design of Concrete Incorporating Waste Foundry Sand (폐주물사를 혼입한 콘크리트의 적정배합설계)

  • 박제선;윤경구;김태경;백민경
    • Magazine of the Korea Concrete Institute
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    • v.9 no.6
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    • pp.195-206
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    • 1997
  • 산업폐기물인 폐주물사를 재활용하여 에너지절감과 환경오염방지효과를 얻을 수 있다. 반요인실험법을 사용하여 폐주물사를 잔골재에 일정비율 치환한 콘크리트의 적정배합설계제시를 위한 예비실험에서 물-시멘트비, 폐주물사의 잔골재치환율, 잔골재율, 슬럼프와 같은 주요변수와 변수사이의 2차상호작용을 파악하였다. 예비실험결과 폐주물사의 잔골재치환율 70%까지 실시하였을 때 폐주물사를 혼입한 콘크리트의 강도 발현에 가장 중요한 변수는 물-시멘트비로 분석되었고 폐주물사의 잔골재치환율은 거의 영향이 없는 것으로 분석되어 폐주물사를 콘크리트의 잔골재로 대체할 수 있음을 알 수 있었다. 각 변수의 2차상호작용에서는 폐주물사의 잔골재치환율과 잔골재율의 상관관계가 콘크리트의 강도발현에 가장 큰 영향을 미치는 것으로 나타났다. 목표압축강도에 대한 적정배합조건을 폐주물사의 잔골재 치환율에 따라 물-시멘트비, 잔골재율에 대해 제시하였다.

Environmental Quality Assurance for Utilization of Waste Concrete (폐콘크리트의 유효활용을 위한 환경특성 평가)

  • 이용수;현재혁;정하익;정형식
    • Journal of the Korean Geotechnical Society
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    • v.17 no.2
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    • pp.143-150
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    • 2001
  • 최근 국내에서는 건설재료의 부족으로 건설부산물인 폐콘크리트를 새로운 토목재료로써 재활용 또는 자원화에 노력하고 있다. 이러한 차원에서 폐콘크리트의 재활용 및 자원화는 사용용도에 적합한 공학적 특성뿐만 아니라 환경적 특성을 분석하여 대상재료의 환경 안정성을 파악해야 한다. 따라서, 본 논문은 폐콘크리트에 대하여 pH시험, 용출시험, 중금속 흡착특성 등 일련의 환경특성 실험을 실시하여 폐콘크리트 사용에 따른 주변 환경에 미치는 영향을 분석하였다. 실험결과, 폐콘크리트의 pH는 11~12정도이고, 폐기물공정시험법과 TCLP법에 의한 용출시험은 법적기준에 모두 만족하는 것으로 나타났다. 또한 중금속 흡착시험은 폐콘크리트나 구리, 납, 카드늄의 제거능이 큰 것으로 나타났으나 반면, 크롬에 대해서는 제거율이 50%정도로 나타났다.

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Flowability and Strength Properties of Mortar and Self-Compacting Concrete Mixed with Waste Concrete Powder (폐콘크리트 분말을 혼합한 모르타르 및 자기충전 콘크리트의 유동 및 강도특성)

  • Choi, Yun-Wang;Jung, Moon-Young;Moon, Dae-Joong;Kim, Sung-Su
    • Journal of the Korea Concrete Institute
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    • v.18 no.4
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    • pp.517-526
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    • 2006
  • In this study, in order to utilize waste concrete powder(WCP) which is occurred in manufacturing high quality recycled aggregate as an admixture for self-compacting concrete(SCC), the properties of cement paste, mortar, and concrete that were mixed two types of WCP, 928 and 1,360 $cm^2/g$ of surface area, were analyzed. As a result of experiment, we have found that WCP was a porous material with angle. When WCP was utilized as an admixture for SCC, its flowability and viscosity increased in proportion to the increase of a replacement ratio, and that a replacement ratio of WCP was proper within 15%. The compressive strength at 28 days mixed respectively with WCP2, 15 and 30%, showed about 36 and 28 MPa, and it showed a similar trend with a function suggested in CEB-FIP for the relationship of compressive strength and elastic modulus. According to the results, it is judged that WCP2 can be utilized as an mineral admixture of normal strength SCC.

A study on the application of waste concrete powder as a material for construction (건설용 재료로써 폐콘크리트 미분말의 활용성 연구)

  • Kim, Yong-Jic;Choi, Yun-Wang;Kim, Sang-Chel;Kim, Young-Jin
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.4
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    • pp.88-94
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    • 2012
  • This study is conducted to utilize waste concrete powder made as a by-product manufacturing high quality recycled aggregate. The blaine fineness of the used waste concrete powder was 928 and $1,360cm^2/g$. As the main characteristic of waste concrete powder, it showed an angular type similar to cement, but hydrated products were attached on the surface of particles. In addition, the size of the particles of waste concrete powder was larger than OPC and in terms of chemical components it had higher $SiO_2$ contents. The viscosity of the paste that mixed waste concrete power decreased by 62% at the most, compared to the paste that only used OPC, and the final set time was delayed about two hours. As composition rates of waste concrete powder increased, the flow value decreased by 30% at the most according to the comparison with mortar that only used OPC, and sorptivity coefficients increased by 70%. The compressive strength of mortar decreased by 73% at the most as composition rates of waste concrete powder increased. According to the test results, it is desirable to use waste concrete powder by combining OPC appropriately(below 15%).

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Experimental Performance Characteristics of Crumb Rubber-Modified(CRM) Asphalt Concrete (폐타이어활용 아스팔트 콘크리트의 실험적 공용특성)

  • Kim, Nak-Seok
    • Journal of Korean Society of Hazard Mitigation
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    • v.3 no.2
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    • pp.89-97
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    • 2003
  • Indirect tensile strength(IDT) test and resilient modulus(Mr) test were performed to evaluate experimental performance characteristics for the conventional and crumb rubber-modified(CRM) asphalt concrete using dry and wet processes asphalt. The IDT test was conducted under three temperatures(5, 10, 20$^{\circ}C$). According to the test results, it was shown that indirect tensile strength of CRM asphalt concrete was lower than that of the conventional one. However, toughness and maximum vortical strain of the CRM asphalt concrete were higher than those of the conventional one. The results of Mr test were presented that Mr of CRM asphalt concrete was higher than that of the conventional one. In addition, it was revealed that the overall laboratory performance characteristics of the wet-processed CRM asphalt concrete was better than those of the dry-processed one.

Application of Waste Concrete Powder as Silica Powder of Cement Extruding Panel (시멘트 압출패널의 규사분말 대체재로서 폐콘크리트 미립분의 활용)

  • Kim, Jin-Man;Kim, Kee-Seok;La, Jung-Min;Choi, Duck-Jin
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.1
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    • pp.88-94
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    • 2011
  • To make recycling aggregate, quantity of fine particles increase due to multi-crushing. Though this particles were mixed with recycling aggregate, those have to be disparted from aggregate in the high quality recycling aggregate, because of the cause of low quality. Considering reactivity, fine particles is better than coarse one. Therefore, it needs to develop suitable usage. We try to make cement extruding material by using the fine particles from concrete recycling, as a silicious replacement. Test results are as follows ; 1) Waste concrete powder has major ingredients such as $SiO_2$ and CaO, its density is $2.45g/cm^3$ being similar to silica powder, its diameter is range 13 to $141{\mu}m$. 2) Considering to strength properties according to particle size, specimen was made using small particles is higher strength than large one. 3) Despite of exception in the autoclaved curing, when the replacement of waste fine particle increase, strength of extruding panel shows almost same level.

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Recycling Plan for Waste Concrete Fine Aggregate as Materials of Anti-Frost Layer and Sub-Base Layer (도로의 동상방지층 및 보조기층재로서 폐콘크리트 잔골재의 재활용 방안)

  • Lee, Dong-Wook;Yun, Jung-Mann
    • Journal of the Korean Geosynthetics Society
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    • v.11 no.3
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    • pp.19-25
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    • 2012
  • In this study, a recycling plan for waste concrete fine aggregate as fill material was researched by investigating environmental engineering properties. It is noted that the environmental influence of waste concrete fine aggregate is little since chemical level is satisfied the waste management standard. Waste concrete fine aggregate is not suitable for materials of anti-frost layer and sub-base layer since the particle-size distribution and engineering properties are not partially satisfied the quality standard. However, waste concrete fine aggregate can be recycled as materials of anti-frost layer and sub-base layer if we improve the engineering properties by mixing bigger aggregates than maximum particle size (5 mm) more than 25 percent of total weight.

물-시멘트비에 따른 굳은 재생콘크리트의 특성

  • 구봉근;김태봉;신재인;박재성;김정회
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • pp.321-326
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    • 1998
  • 폐콘크리트양은 건설폐기물 발생량의 약 50%정도인 연간 약 500만톤 이상으로 추정하고 있다. 따라서, 건설폐기물인 폐콘크리트에 대한 적절한 기술적 처리와 재활용 시스템이 구축된다면 도로포장 및 기타 포장 하층노반재료, 재생 입도조정쇄석, 건축물의 기초재, 토목 구조물의 기초재, 공작물의 되메우기 재료 등으로 활용될 수 있어 폐기되어버릴 단순한 쓰레기가 아니라 오히려 재활용 용도를 적극 개발하여야 할 중요한 자원이라고 볼 수 있다. 본 연구의 목적은 여러가지 건설 폐기물 중에서도 재활용 가능성이 높으며 구조물 해체시 다량으로 얻어지는 폐콘크리트를 대상으로 건설공사에 재이용하기 위해 폐콘크리트 골재를 사용한 재생콘크리트의 공학적 특성을 실험을 통해 검토하고자 하는 것이다. (중략)

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A Study for Recycling CO2 Silicate Bonded Waste Foundry Sand as Fine Aggregate for Concrete (CO2형 폐주물사를 콘크리트용 잔골재로 재활용하기 위한 연구)

  • 문한영;최연왕;송용규
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.420-429
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    • 2002
  • The amount of $CO_2$-silicate bonded waste foundry sand(WFS) occurred in Korea is over 800,000 ton per year. WFS, as a by-product, is generated through manufacturing process of foundry may affect our environmental contamination, The reason is that WFS has been buried itself not less than 90% out of total WFS. So, it can give damage on the ground of contamination in soil and underwater. Therefore, it is necessary to establish the method recycling WFS because of being intensified waste management law. In this study, we performed the research with respect to harmful component analysis, the qualities of WFS mortar and concrete mixed with WFS. As the results the specific gravity of WFS is the same as that of natural aggregate while unit weight and percentage of solids of WFS are smaller than those of it. But it is found that WFS can be used by substituting WFS for natural aggregate after control of poor grade of WFS. The flowability of mortar and concrete with WFS is inferior to those of natural aggregate, and the setting time of concrete with WFS is faster than that with only natural aggregate, On the contrary, the bleeding of concrete with WFS is shown good result, and compressive and tensile strength of concrete substituted WFS for 30% are higher than those with only natural aggregate regardless of elapsed time.