폐주물사의 치환율 변화에 따른 모르타르의 특성 분석

류현기,권용주,Ryu, Hyun-Gi,Kwon, Yong-Ju 한국건설순환자원학회 2009 한국건설순환자원학회지 Vol.4 No.4

폐주물사의 재활용을 위하여 최근 연구자들은 매립에 의존하지 않고 리사이클링하기 위해 노력하고 있으며, 폐주물사의 효율적인 재활용방법으로 시멘트와 결합하여 각종 건설용 자재로 사용하는 방법을 연구하고 있다. 본연구에서는 폐주물사를 대체 잔골재로 사용하여 1:2, 1:3, 1:5의 배합으로 부 빈배합의 예비실험을 통해 폐주물사의 성상을 실험적으로 검토하여 폐주물사를 적용할 수 있는 범위를 배합비 1:3의 W/C 43%와 50%의 2개 수준에 대한 실험으로 폐주물사의 적정 대체율을 찾아 활용할 수 있는 방안을 제안한다. 실험결과 굳지않은 모르타르의 특성으로 유동성은 폐주물사의 대체율이 증가 할수록 플로우는 감소하는 것으로 나타났으며, 공기량도 유동성과 유사한 경향으로 폐주물사의 대체율이 증사 할수록 감소하는 것으로 나타났다. 경화모르타르의 강도특성은 폐주물사를 치환 할수록 강도는 증가하는 것으로 나타났고, 폐주물사를 치환함으로써 초기강도가 증가하는 것을 알 수 있다. 수밀특성으로 투수량과 흡수량은 폐주물사의 미립분에 의해 공극충전효과로 투수량이 감소하는 것으로 나타나 수밀성을 요구하는 구조물에 폐주물사의 치환은 효과적일 것으로 사료된다. For recycling of waste foundry sands, researchers recently try to recycle them rather than depend on reclamation, and are studying on how to combine waste foundry sands with cement and use them for various kinds of construction material as the effective recycling method of waste foundry sand. In this research, The ways to find the proper replacement rate of waste foundry sands and to make use of them were suggested through the experiments on the range to apply waste foundry sands with two levels of 1:3 mixture rate of W/C 43% and 50%. The research result showed that in terms of liquidity as the characteristic of unhardened mortar, as the replacement rate of waste foundry sands increased, its flow tended to decrease. The amount of air also displayed a similar tendency to that of liquidity in that the higher the replacement rate of waste foundry sands became, the lower it became. With regard to the solidity trait of hardened mortar, it increased when the waste foundry sands were replaced more, and the replacement of waste foundry sands caused increased initial solidity. As for the amount of water permeated and that of water absorbed as the water tight proofing properties, the amount of permeated water was proved to decrease because of the gap recharge effect by the fine powder of waste foundry sands, and the replacement of waste foundry sands in the structures requiring watertightness is concluded to be very effective.

폐도자기 분말도 변화에 따른 순환골재 사용 콘크리트의 물리적 특성에 관한 연구

류현기,박정민,정재호,김의창,윤승조,Ryu, Hyun-Gi,Park, Jeong-Min,Joung, Jae-Ho,Kim, Eui-Chang,Yoon, Seung-Joe 한국건설순환자원학회 2011 한국건설순환자원학회지 Vol.6 No.2

본 연구의 목적은 폐도자기 분말도 변화에 따른 순환골재 강도 증진에 관한 연구로 유동성은 폐도자기 분말 치환율이 증가할수록 유동성이 감소하는 경향으로 나타났으며, 공기량은 KS 한도범위를 만족하는 것으로 나타났다. 압축강도는 순환골재 및 폐도자기 분말 치환율이 증가할수록 증가경향이고, 내구성으로 건조수축에 의한 길이변화는 폐도자기 미분말이 커질수록 다소 완만한 건조수축율을 나타내었고, 또한 단열온도상승은 순환골재 대체율 및 폐도자기 미분말이 증가할수록 최고온도에서 약 $6{\sim}10^{\circ}C$정도 낮게 나타내어 수화열에 의한 균열저감 효과를 발휘하였다. 순환골재 사용량을 30%정도 권장 하고 있지만 점토인 폐도자기의 분말도를 조절하여 사용할 경우 순환골재의 다량 사용시에는 콘크리트의 제반성상에 문제가 없을 것으로 판단되었다. Objective of this study is to identify properties on strength increase of hardened concrete and fluidization of non-hardened concrete using waste ceramics generated by construction waste, which is a type of industrial waste, and by ceramics, which is a clay plastic, during its production process, and determine length change ratio caused by drying shrinkage during substitution of recycle aggregate and waste ceramics, and whether they can be used as concrete compounds. Slump of non-hardened concrete exhibited the best fluidization and formability at recycled aggregate's replacement ratio of 60% driven by higher substitution ratio of recycled aggregate and waste ceramics while air content met the KS requirement when substitution ratio of waste ceramics was $4,000cm^2/g$. Compressive strength of hardened concrete exceeded the requirements at early age and standard age and temperature dropped by roughly $6{\sim}10^{\circ}C$ less than the standard at maximum temperature in adiabatic temperature increase, which will hopefully result in stronger durability.

콘크리트용 혼화재로써 왕겨 및 볏짚재의 활용가능성에 관한 연구

류현기(Ryu Hyun-Gi),박정민(Park Jeong-Min) 대한건축학회 2011 大韓建築學會論文集 : 構造系 Vol.27 No.5

This research aims at obtaining rice husk ash and rice straw ash by burning rice husk and rice straw. The agricultural by-products, examining the flowability of fresh concrete. Mechanical properties and the possibility to react to pozzolan of hardened concrete, and the length change rate by dry shrinkage, and assessing whether they are able to be applied as the mixture material of concrete. In case of the slump of fresh concrete, rice husk ash had better liquidity and the possibility to make forms with it than rice straw ash. The amount of air was proper for KS standard at 5% of rice husk ash and rice straw ash. In terms of the compressive strength of hardened concrete, the strength of the RHA of early age was smaller than the standard, and the strength of rice straw ash at the replacement rate of 5% and 10% was bigger than the standard, except for that at the replacement rate of 15%. The strength of RHA of standard age and 10% of RSA were bigger than the standard at all replacement rates. The pozzolan activity factor was higher than the standard at the standard age, regardless of the type of mixture material and replacement rate, so it can be concluded to have the possibility to react to pozzolan. The analysis result of SEM photographing proved that rice straw ash is a heterogeneous material with mixed big and small granules, and their linkage of reaction is long and surface is rough, which is estimated to affect the manifested strength.

카본계 흡착재를 이용한 수질개선용 친환경 콘크리트 개발에 관한 기초적 연구

류현기(Ryu Hyun-Gi),우종권(Woo Jong-Kwon) 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.12

The research pursues to establish foundation to manufacture concrete for water tanks and channels to improve water quality; the purpose is to set mixture ratio according to various replacement rate for carbon absorbent, to analyze physical property of concrete, and to seek methods to apply concrete in an environment-friendly manner. The result showed that in case of fresh concrete, as the replacement rate for carbon absorbent increased, air volume and slump declined, while the amount of bleeding increased. Regarding hardened concrete, as the replacement rate for carbon absorbent increased, compressive and tensile strength, and change of length decreased, while the absorptivity increased. In evaluating water quality, the amount of floating material and heavy metals Cu?, Cd? decreased by 20~40% with increasing replacement rate for carbon absorbent.

운모폐석을 잔골재로 사용한 시멘트 모르타르의 특성

윤기원(Yun, Gi won),金光華(Jin, Guang Hua),오상백(Oh, Sang Baeg),한민철(Han, Min Cheol),류현기(Ryu, Hyun Gi),한천구(Han, Cheon Goo) 한국콘크리트학회 2003 한국콘크리트학회 학술대회 논문집 Vol.2003 No.11

시험체의 형상이 슈미트햄머법 비파괴시험에 미치는 영향

김현우 ( Kim Hyun-woo ),이종태 ( Lee Jong-tae ),윤기원 ( Yoon Gi-won ),류현기 ( Ryu Hyun-gi ),한천구 ( Han Cheon-goo ) 한국구조물진단유지관리공학회 1999 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.3 No.1

Recently, non-destructive test method by Schmidt hammer is one of the strength estimation methods used widely in field. In this paper, the relationships between existed formula and suggested one in this study are investigated testing compressive strength and rebound number of Schmidt hammer. Compressive strength and rebound number according to the shape of specimens and the kinds of forms are also tested. According to the test results, compressive strength and rebound number of cylindrical specimens is smaller than those of cubic specimens. In case of rebound number test, there are no differences between cylindrical specimens (φ 15x30cm) and cubic specimens(20x20x20cm). We can find the differences of rebound number with the kinds of forms.

왕겨재 및 볏짚재를 콘크리트용 혼화재로 이용한 특성분석

박정민(Park Jeong-Min),류현기(Ryu Hyun-Gi) 한국정보기술학회 2011 Proceedings of KIIT Conference Vol.2011 No.5

This research aims at obtaining rice husk ash and rice straw ash by burning rice husk and rice straw. The agricultural by-products, examining the liquidity of fresh concrete. Dynamic properties and the possibility to react to pozzolan of hardened concrete, and the length change rate by dry and contraction, and assessing whether they are able to be applied as the mixture material of concrete. In case of the slump of fresh concrete, rice husk ash had better liquidity and the possibility to make forms with it than rice straw ash. The amount of air was proper for KS standard at 5% of rice husk ash and rice straw ash. In terms of the compressive strength of hardened concrete, the strength of the RHA of early age was smaller than the standard, and the strength of rice straw ash at the replacement rate of 5% and 10% was bigger than the standard, except for that at the replacement rate of 15%. The strength of RHA of standard age and 10% of RSA were bigger than the standard at all replacement rates. The pozzolan activity factor was higher than the standard at the standard age, regardless of the type of mixture material and replacement rate, so it can be concluded to have the possibility to react to pozzolan. The analysis result of SEM photographing proved that rice straw ash is a heterogeneous material with mixed big and small granules, and their linkage of reaction is long and surface is rough, which is estimated to affect the manifested strength.

칡뿌리 섬유소를 이용한 섬유보강 콘크리트의 특성 분석

박정민(Park Jeong-Min),류현기(Ryu Hyun-Gi) 한국정보기술학회 2011 Proceedings of KIIT Conference Vol.2011 No.5

The fiber reinforced concrete, one kind of solution to supplement the defects of concrete, has the strong point to decrease the weight of concrete and decrease the cracks. Recently, other materials in addition to the existing cellulose are used a lot to improve the capacity of concrete, but are causing harm on human bodies by emitting Endocrine disruptor and hazardous materials, and more environmentally friendly materials are required to be developed. The cellulose of arrowroots, which were frequently used as cloth and wallpaper in the past, holds higher imprint strength and light weight and is a natural cellulose, so when it's used as the fiber reinforcing material of concrete, not only the performance of concrete will be improved, but also it can be developed as a new environmentally friendly fiber material. Accordingly, the natural and artificial cellulose of arrowroots was mixed with concrete, and the properties of unsolidified concrete and hardened concrete were examined and analyzed. The results can be summarized as follows: when the natural and artificial cellulose of arrowroots was mixed with concrete, the increase in the rate of mixture brought about the decrease in the slump and in the time of solidification. The compressive and imprint strength was observed to increase, and the possibility to absorb CO2 and the decrease of formaldehyde density was satisfactory.

거친 환경에 최적화된 가속도계 무선 데이터 로깅모듈

박승호(Seung-Ho Park),류현기(Hyeon-Gi Ryu),이창민(Chang-Min Lee),김상현(Sang-Hyun Kim),정회인(Hoe-In Jeong),박경수(Kyoung-Su Park) 한국소음진동공학회 2020 한국소음진동공학회 논문집 Vol.30 No.6

콘크리트의 초기 강도발현에 미치는 혼화제의 영향

황인성(Hwang, Yin Seong),나운(La, Woon),이승훈(Lee, Seung Hoon),류현기(Ryu, Hyun Gi),한천구(Han, Cheon Goo) 한국콘크리트학회 2003 한국콘크리트학회 학술대회 논문집 Vol.2003 No.5