재생골재를 사용한 콘크리트의 특성에 관한 연구

박영신,지석원,이세현,서치호 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

The production of waste concrete is increased continuously by urban renewal and reconstruction, and the positive use of recycled concrete aggregates is needed. In this study, it is examined mechanical properties of recycled aggregates concrete used recycled fine and coarse aggregates for the technology development of the highly use of recycled aggregates. In the experiment. Recycled coarse aggregates is substitute for the rate of 0, 30, 60%, and recycled fine aggregates is substitute for natural aggregates the rate of 0, 25, 50, 75, 100% each. The result of the experiment is followed. 1. The slump and variation of slump as the time, is decreased irregularly according to the substitutive ratio of recycled aggregates, and the air content is increased. 2. The compressive and tensile strength is decreased according to the substitute ratio of recycled aggregates, but in the recycled aggregates 25%, the increase of strength is shown about 5% compared with normal concrete.

재생골재 생산방식의 차이에 따른 재생 굵은골재의 품질 특성에 관한 비교 연구

심종우,이문환,이세현,전현규 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

The purpose of this study is intended for effective recycling of waste concrete. It analyzes the quality 0 the recycled coarse aggregate with production types. The conclusions of the study are as follows. 1. The recycled coarse aggregate which is produced through 5th Crushing Process (A-Type) shows the improvement in grading and particle shape, reduction in an absorption rate until 1.14% due to removal of attached the mortar and paste. Therefore, it satisfies the standards of KS F 2573(recycled aggregate for concrete) as the first grade. 2. The recycled coarse aggregate which is produced through 3rd Crushing Process(B-Type) is suited to the quality prOVlSlOns of the standards of KS F 2573, shows a 3.12% absorption rate that is second grade as recycled coarse aggregate. Based on the above results, it is possible to product first and second grade recycled coarse aggregates with production types. It is concluded that recycled coarse aggregate with production types can be used as aggregate within required conditions. And more researches are also needed to make recycled coarse aggregate better to use for concrete.

순환굵은골재를 사용한 레디믹스트 콘크리트의 역학적 특성

전에스더(Jeon Esther),윤현도(Yun Hyun-Do),지상규(Ji Sang-Kyu),최기선(Choi Ki-Sun),유영찬(You Young-Chan),김긍환(Kim Keung-Hwan) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.8

In this study, the mechanical properties of ready-mixed concrete with recycled coarse aggregate(RCA) were discussed. The mixing types were composed of twelve series based on specified compressive strength(i.e 21, 27, and 40MPa) and replacement ratio of recycled coarse aggregates(i.e 0, 30, 60 and 100%). Recycled coarse aggregate utilized in the study consists of 71.43% high quality recycled coarse aggregate, 28.57% low quality recycled coarse aggregate by weight. The properties of the fresh concrete were measured by means of slump and air content according to elapsed time. The strength properties of the hardened concrete were measured by means of compressive strength, splitting strength and modulus of rupture. Also test result were compared with existing domestic Codes(KBC2005 and KCI2007). Test result indicated that the replacement ratio of recycled coarse aggregate had little effect on fresh properties, such as slump and air content, of RCA concrete. Compressive strength, splitting strength and modulus of rupture of concrete is little affected by the replacement ratio of recycled coarse aggregate. And elastic modulus, splitting strength and modulus of rupture show relatively low values compared with relevant provisions in KBC2005 and KCI2007. Therefore, some design coefficients or recommendations in existing design code for natural aggregate concrete need to be amended for recycled aggregate concrete.

순환굵은골재 치환율 및 양생방법에 따른 콘크리트의 압축강도특성

전에스더(Jeon Esther),윤현도(Yun Hyun-Do),최기선(Choi Ki-Sun),유영찬(You Young-Chan),이세현(Lee Sea Hyun),이도헌(Lee Do-Heun) 대한건축학회 2007 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.27 No.1

Recycling demolished concrete as an alternative source of coarse aggregates for the production of new concrete can help solve the growing waste disposal crisis and the problem of depleted natural aggregates. However, to make such recycling feasible, the strength and durability of the recycled aggregate concrete must be assured. In this paper, fresh(air contents, slump) properties and the compressive strength of recycled aggregate concrete according to curing method are investigated experimentally. Concrete specimens were fabricated by ready-mix concrete and tested with different recycled coarse aggregate replacement level of 0%, 30%, 60% and 100%, respectively. For recycled coarse aggregate concrete, the change of air contents were bigger than natural coarse aggregate concrete. The air-cured/water cured strength ratio of recycled coarse aggregate concrete was 84.23~99.39%. Compressive strength of concrete with different recycled coarse aggregate replacement level was shown to be similar.

재생굵은골재를 사용한 고강도 콘크리트의 동결융해 특성

성찬용,임상혁,Sung , Chan-Yong,Im , Sang-Hyuk 한국농공학회 2004 한국농공학회논문집 Vol.46 No.2

This study was performed to evaluate the freezing and thawing properties of the high strength concrete using recycled coarse aggregate. The recycled coarse aggregate replaced natural crushed aggregate by 0%, 25%, 50%, 75% and 100%. The compressive strength of the concrete using recycled coarse aggregate showed more than 300 kgf/$cm^2$ at the curing age 28 days. The mass loss ratio by freezing and thawing was less than 1% at all mix type. The relative dynamic modulus of elasticity was decreased with increasing the freezing and thawing cycles. Also, the durability factor by the freezing and thawing was decreased with increasing the content of recycled coarse aggregate. But, the recycled concrete except 100% recycled coarse aggregate showed 60 or more durability factor in the freezing and thawing 300 cycles. Accordingly, these recycled coarse aggregate can be used for high strength concrete.

재생굵은골재를 사용한 콘크리트의 동결융해 특성

성찬용,윤준노,김영익,임상혁,정덕현 충남대학교 농업과학연구소 2003 농업과학연구 Vol.30 No.2

이 연구는 플라이 애시를 결합재 중량의 20%, 재생굵은골재를 천연쇄석굵은 골재의 0%, 25%, 50%, 75%, 100%를 치환하여 압축강도와 동결융해 특성을 구명하였으며, 이 연구를 통해 얻어진 결과를 요약하면 다음과 같다. 1. 재령 28일의 압축강도는 모든 배합비와 W/B 35%에서 400㎏f/㎠이상으로 나타나 고강도콘크리트에 이용될 수 있을 것으로 생각된다. 2. 중량감소율은 동결융해 300사이클에서 1%미만으로 나타났고, 표면박리와 같은 현상은 나타나지 않았으며, 재생골재의 대체율이 증가할수록 감소율은 증가하였다. 3. 초음파진동속도는 동결융해 300사이클에서 19~24%정도의 감소율을 나타내었으며, 재생골재의 대체율이 증가할수록 감소율은 증가하는 경향을 나타내었다. 4. 상대동탄성계슈는 재생골재의 대체율에 따라 60~72%의 범위로 나타내었으며, 재생골재 대체율이 증가할수록 감소하는 경향을 나타내었다. 5. 내구성지수는 모든 배합에서 60이상을 나타내었으나, 재생골재 대체율이 100%일때는 급격히 떨어지는 경향을 나타내었다. 6. 재생굵은골재를 사용한 콘크리트의 압축강도, 중량감소율, 초음파진동속도, 상대동탄성계수, 내구성지수 시험결과를 볼 때, 시험에 사용한 재생굵은 골재는 고강도콘크리트에 사용이 가능할 것으로 판단된다. This study was performed to examine the freezing and thawing properties of the high strength concrete using recycled coarse aggregate. The recycled coarse aggregate was replaced by 0%, 25%, 50%, 75% and 100% of natural crushed aggregate. The compressive strength of the concrete used recycled coarse aggregate was shown in more than 400kgf/㎤ at the curing age 28 days. The weight loss ratio by freezing and thawing was shown in less than 1% at all mix type. The pulse velocity and relative dynamic modulus were decreased with increasing the freezing and thawing cycles. Also, durability factor for the freezing and thawing were decreased with increasing the content of recycled coarse aggregate. But, recycled concrete replaced with recycled coarse aggregate 100% was shown in more than 60 by durability factor in freezing and thawing of 300cycles Accordingly, these recycled coarse aggregate can be used for high strength concrete.

재생골재를 콘크리트용 골재로 사용하기 위한 기초 물성 연구

공경록,강헌찬 東亞大學校 附設 環境問題硏究所 2004 硏究報告 Vol.26 No.-

This study research the method that it will be able to increase the demand of the quality of the construction waste and recycled aggregate. It includes a test for sieve analysis of aggregate, a test for specific gravity, a test for absorption, a test for impurity contents and crisis effect of cement paste of recycled aggregate. The grain size change of the 13~45mm recycled aggregate by the crusher when moving toward the 2nd cone crusher from the 2nd jaw crusher, the content change from 6.69% changed with 55.34%. The recycled aggregate of 13~45mm includes a standard grain size distribution. A test of impurity contents was resulted 1.49%. Density of the recycled aggregate of 13~45mm was 2.14g/㎤ and water absorption ratio was 7.74%. Content of the aggregate where the cement paste sticks below 50% changed 8.35% → 12.68% → 13.76% → 23.61% → 23.67% when first jaw crusher → second jaw crusher → first cone crusher → double screen → recycled aggregate of 13~45mm. The crisis of the recording aggregate which will be rough the crusher and the cement paste goes well. For the recycled aggregate production of quality the development of the system which separates the recycled aggregate is necessary.

Rheological, physico-mechanical and durability properties of multi-recycled concrete

Rahmani, Abdessamed Azzaz,Chemrouk, Mohamed,Ammar-Boudjelal, Amina Techno-Press 2020 Advances in concrete construction Vol.9 No.1

The present work looks at the possibilities of recycling more than once demolished concrete as coarse aggregates, to produce new concrete. Different concrete mixes were made with substitutions of 50%, 75% and 100% of recycled concrete aggregates respectively as coarse aggregates. The physico-mechanical characterization tests carried out on the recycled concrete aggregates revealed that they are suitable for use in obtaining a structural concrete. The resulting concrete materials had rheological parameters, compressive strengths and tensile strengths very slightly lower than those of the original concrete even when 100% of two cycles recycled concrete aggregates were used. The durability of the recycled aggregates concrete was assessed through water permeability, water absorption and chemical attacks. The obtained concretes were thought fit for use as structural materials. A linear regression was developed between the strength of the material and the number of cycles of concrete recycling to anticipate the strength of the recycled aggregates concrete. From the results, it appear clear that recycling demolished concrete represents a valuable resource for aggregates supply to the concrete industry and a the same time plays a key role in meeting the challenge for a sustainable development.

순환 굵은 골재와 부순 굵은 골재의 혼합비율에 따른 혼합 굵은 골재 품질특성에 관한 기초적 연구

윤상혁,이세현 한국폐기물자원순환학회 2020 한국폐기물자원순환학회지 Vol.37 No.7

The density based on the mixing ratio of recycled coarse aggregate and crushed coarse aggregate decreased as the mixingratio increased, and the absorption rate increased. Based on the mixed coarse aggregate’s quality characteristics showedthe highest performance at the mixing ratio of 20 to 80. exhibited. Furthermore, the recycled coarse aggregate satisfyingthe KS F 2527 standard can be used for ready-mixed concrete production up to 80%. The particles resulting from theincrease in the mixing ratio of recycled coarse aggregate is applicable as mixed coarse aggregate for ready-mixed concreteproduction

순환 굵은 골재의 함수상태와 양생조건에 따른 콘크리트의 압축강도

문경태,박상렬,김승은 대한토목학회 2019 대한토목학회논문집 Vol.39 No.4

In this study, the effect of moisture conditions of recycled coarse aggregates on the compressive strength of concrete was evaluated with the water/binder ratios and the curing conditions. The saturated recycled aggregates seemed to have the negative effect on the strengthdevelopment of concrete. This is the because of the decrease in bond strength between aggregate and cement paste due to the increaseof surface water according to the high absorption of recycled aggregates. The effect of types and moisture conditions of aggregatesaccording to the change of water/binder ratio was similar. However, the curing conditions had a significant effect on the compressivestrength of the concrete with the different types of aggregates. In the case of curing in air, the recycled aggregates with high absorptionreduced the moisture required for hydration and increased the rate of vaporizing, and these result in interfering strength development. The moisture conditions of the recycled aggregates have a considerable effect on the compressive strength of the concrete, and it is necessary to control the moisture conditions of aggregates in the production of concrete with recycled coarse aggregate. And the controlof the curing condition is very important for the concrete with recycled aggregate. 본 연구는 순환 굵은 골재의 함수상태가 콘크리트의 압축강도에 미치는 영향을 물/결합재 비와 양생 조건을 변수로 하여 평가하였다. 표건상태의 순환골재는 콘크리트의 강도발현을 저하시켰는데, 이는 순환골재의 높은 흡수율에 의한 표면수의 증가로 골재와 시멘트 페이스트 사이의 부착강도가 저하되었기 때문이다. 골재의 종류와 함수상태가 물/결합재 비의 변화에 따라 압축강도에 미치는 영향의 정도는 비슷하였다. 그러나 양생조건에 대해서는 골재의 종류에 따라 상당한 차이를 보였다. 대기양생을 시킨 경우 높은 흡수율을 가진 순환골재는 수화작용에 필요한 수분을 감소시키고, 수분증발을 증가시켜 강도발현을 저해하였다. 순환골재의 함수상태는 콘크리트의 압축강도에 상당한 영향을 줬으며, 순환골재콘크리트 생산시 골재의 흡수율에 따른 함수상태에 대한 관리가 필요하다. 또한 순환골재 콘크리트의 경우 적절한 품질관리를 위해 양생관리가 매우 중요하다.