• 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.

• 한국건축시공학회지
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• 제12권1호
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• pp.73-86
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• 2012

In this research, the possible applicability of mixture blended with natural, crushed, and recycled fine aggregate are discussed. The fresh and hardened properties of mortar using blended fine aggregates are monitored depending on various blending ratio of fine aggregates. Newly developed ternary diagram was also utilized for better interpretation of the data. It was found that air content increased and unit weight decreased as recycled fine aggregate content increased. With moisture type processing of recycled fine aggregate, the mortar flow was not negatively affected by increase in the recycled fine aggregate content. The ternary diagram is found to be an effective graphical presentation tool that can be used for the quality evaluation of mortar using blended fine aggregate.

• 한국건설순환자원학회논문집
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• 제5권4호
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• pp.359-365
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• 2017

본 연구에서는 KS F 2573 콘크리트용 순환골재 기준에 적합한 순환잔골재의 치환율에 따른 콘크리트 특성을 검토하였다. 물리적 특성으로 슬럼프, 공기량, 경시변화, 압축강도에 대한 연구를 수행하였으며, 순환잔골재 재활용 활성화를 위한 기초자료를 제공하고자 한다. 슬럼프 경시변화 실험 결과 순환잔골재의 치환율 증가에 따라 슬럼프 경시변화 감소율은 커지는 것으로 나타났다. 공기량 측정 결과 순환잔골재의 치환율 증가에 따라 공기량 또한 증가하는 것으로 나타났으며, 경시변화의 경우 공기량 감소율은 낮아지는 것을 확인하였다. 반면 100% 치환 시 천연골재콘크리트보다 높은 공기량을 나타내 강도저하가 발생할 것으로 사료된다. 압축강도의 실험 결과 순환잔골재 치환율 증가에 따라 강도저감이 발생했으며, 24MPa 배합 결과 30% 치환 시 천연골재콘크리트와 동등한 강도발현을 나타냈다. 위의 결과를 토대로 순환잔골재 30%치환 시 천연골재콘크리트와 동등한 물리적 특성을 나타내 KS F 2573 콘크리트용 순환골재 기준에 적합한 순환잔골재 치환 시 목표강도 24MPa의 30%가 적합한 것으로 판단된다. 추후 순환골재의 사용 활성화를 위해 순환잔골재 개질을 통한 품질개선이 필요하며, 후속연구로서 개질된 순환잔골재를 이용한 순환잔골재콘크리트의 물리적 특성 평가가 수행되어야 할 것으로 판단된다.

• 자원리싸이클링
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• 제24권5호
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• pp.63-71
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• 2015

본 연구는 재생 굵은골재와 산업부산물인 급냉 제강슬래그 잔골재를 이용한 친환경 재생 콘크리트의 재료적 특성을 파악하고 적정 혼합비를 도출하는데 그 목적이 있다. 이를 위해서 재생 굵은골재의 치환율은 30%에서 50%까지 증가시켰으며, 급냉 제강슬래그 잔골재는 10%에서 50%까지 증가시켜서 물성실험을 수행하였다. 그 결과, 재생골재의 치환율이 증가함에 따라 강도가 감소하였으나 급냉 제강슬래그 잔골재의 혼입율을 증가함에 따라 강도가 증가됨을 알 수 있었다. 더불어 급냉 제강슬래그 잔골재의 적정 치환율은 압축강도 및 탄성계수 등을 고려했을때 20~30%로 판단되며, 재생 굵은골재의 치환율 증가에도 도움이 될 것으로 사료된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.77-78
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• 2011

This study is analysis of effect of binder types and replacement ratio on the properties of blast furnace slag mortar using the recycled fine aggregates. The results of the study were was follows. Compressive strength was increased according to an increase in replacement ratio of fine particle cement and gypsum. Absorption was reduced according to an increase in replacement ratio of fine particle cement and recycled aggregate fine powder.

• 한국구조물진단유지관리공학회 논문집
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• 제15권4호
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• pp.193-203
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• 2011

본 연구에서는 폐콘크리트에서 발생하는 순환잔골재가 구조용 재료로서 많은 문제점이 있음을 인지하고 순환잔골재가 포함하고 있는 미분말이 강도증진 효과와 유동성을 증가 시킬 수 있다는 특성을 이용하여 자기충전 콘크리트(Self-Compacting Concrete, 이하 SCC로 표기)에 활용하게 되었다. 즉 순환잔골재가 갖는 미분말이 자기충전 콘크리트 특성인 고강도(40 MPa 이상)와 높은 유동성(JSCE 2등급)을 발현하기에 적당하여 폐콘크리트에서 발생하는 순환잔골재를 일반잔골재 대비 순환잔골재의 혼입률을 25%씩 증가시켜, 총 5수준으로 달리하여 자기충전 콘크리트에 적용하였으며, 이에 따라 굳지 않은 콘크리트의 물리적 특성, 경화한 콘크리트의 역학적 및 내구 특성을 검토하여 순환잔골재를 자기충전 콘크리트 재료로서 활용 가능성을 검토하고자 한다. 그 결과 물리적, 역학적 및 내구특성의 5수준 배합비율 중 일반잔골재 대비 순환잔골재는 50% 혼입률까지 적용가능하다는 결론을 얻었으며, 그 이상의 혼입률에서는 오히려 성능저하가 발생한다는 것을 알 수 있었다. 또한 실생활에서의 적용 가능성을 알아보기 위한 실구조물의 적용성이 차후 검토 되어야 할 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.373-376
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• 2008

The objective of this study is to investigate the properties of fresh concrete with recycled fine aggregates. Three different kinds of fine aggregate with natural, high and low quality recycled aggregates were prepared. The concrete mixtures were produced with test parameters of replacement ratio of recycled fine aggregate. The properties of the fresh concrete were measured by means of slump and air content according to elapsed time. Quality control method to maintain the constant total mixing water for recycled aggregate concrete was suggested. The all concrete mixtures were produced with approximately the same slump on the job site after an hour. Test results indicated that compressive strength of the concrete mixtures with constant slump is not affected by the replacement ratio of recycled fine aggregate. Therefore, the practical way for the quality control of recycled aggregate concrete is to maintain the constant total mixing water.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.233-238
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• 2002

In this paper, the characteristics of fresh and hardened recycled concrete were experimentally compared to investigate the applicability of the recycled fine aggregates with the substitution ratio. Test results show that the workability of the recycled concrete decreases with the increment of substitution ratio of the recycled fine aggregates except for type-D case which has a lower absorption ratio. Also air content was increased with increasing substitution ratio. It was found that the compressive strength and elastic modulus of recycled concrete were decreased with increasing substitution ratio of the recycled fine aggregates. And, the superplasticizer was more effective on the workability recovery of the recycled concrete.

• Structural Engineering and Mechanics
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• 제88권2호
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• pp.141-157
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• 2023

In the present paper, the effect of recycled aggregates on the rheological and mechanical properties of self-consolidating concrete is investigated experimentally and numerically. Hence, the specimen with two types of recycled aggregates, i.e., known and unknown resistance origins, are utilized for the studied specimens. The experiments in this study are designed using the Box-Behnken method, which is one of the response surface methods. Input variables in mixtures include silica fume in the range of 5-15% as a percentage substitute for cement weight and recycled coarse and fine aggregates in the range of 0-50% for both series of recycled materials as a substitute for natural materials. The studied responses are slump flow, V funnel, compressive strength, tensile strength, and durability. The results indicate that the increase in the amount of recycled aggregates reduces the rheological and mechanical properties of the mixtures, while silica fume effectively improves the mechanical properties. In addition, the results demonstrate that the fine recycled aggregates affect the total response of the concrete significantly. The results of tensile and compressive strengths indicate that the mixtures including 50% recycled materials with known resistance origin demonstrate better responses up to 8 and 10% compared to the materials with unknown resistance origins, respectively. Recycled materials with a specific resistance origin also show better results than recycled materials with an unknown resistance origin. Durability test results represent those concretes containing recycled coarse aggregates have lower strength compared to recycled fine aggregates. Also, a series of mathematical relationships for all the responses are presented using variance analysis to predict mixtures' rheological and mechanical properties.

• Advances in concrete construction
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• 제5권3호
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• pp.201-219
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• 2017

With the rapid growth in construction sector, it becomes all the more important to assess the amount of Construction and Demolition (C&D) waste being generated and analyze the practices needed to handle and use this waste before final disposal. This serves waste management and disposal issues, paving way to waste utilization in construction industry from the sustainability point of view. C&D waste constitutes a major bulk of total solid waste produced in the world. In this work, an attempt is made to study the performance of concrete using water soaked Recycled Coarse Aggregates (RCA) in replacement levels of 0%, 25%, 50%, 75% and 100% to Natural Coarse Aggregates (NCA). Experiments were designed and conducted to study the performance of RCA based concrete. Further suitable performance enhancement techniques to RCA based concrete were attempted, to achieve compressive strength at least equal to or more than that for no RCA based concrete (control concrete). Performance enhancement study is reported here for 50% and 100% RCA based concretes. All four techniques attempted have given favorable results encouraging use of RCA based concretes with full replacement levels, to adopt RCA based concrete in structural applications, without any kind of concern to the stake holder. Further attempts have also been made to use Recycled Fine Aggregates (RFA) with appropriate modifications to serve as fine aggregates in mortar and concrete. Using RFA blended with river sand fractions as well as RFA with Iron Ore Tailings (IOT) fractions, have given good results to serve as fine aggregates to the extent of 100% replacement levels in mortars and concretes.