• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.743-746
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• 2004

This research investigates experimentally an effect on the properties of the high flowing concrete according to variations of concrete materials and site conditions. Variations of sensitivity test are selected items as followings; (1)Concrete temperature, (2)Unit water(Surface moisture of fine aggregate), (3)Fineness modulus of fine aggregate, (4)Addition ratio of high-range water reducing agent. And fresh conditions of the high flowing concrete should be satisfied with required range including slump flow$(65{\pm}5cm)$, 50cm reaching time of slump flow$(4\~10sec)$, V-box flowing time$(10\~20sec)$, U-box height(min.300mm) and air content$(4{\pm}1\%)$. As results of sensitivity test, material variations and site conditions should be satisfied with the range as followings; (1)Concrete temperature is $10\~20^{\circ}C$ (below $30^{\circ}C$), (2)Surface moisture of fine aggregate is within ${\pm}0.6\%$, (3)Fineness modulus of fine aggregate is $2.6{\pm}0.2$ and (4)addition ratio of high range water reducing agent is within $1\%$ considered flow-ability, self-compaction and segregation resistance of the high flowing concrete.

• Computers and Concrete
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• 제13권3호
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• pp.325-342
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• 2014

The use of lightweight aggregate (LWA) instead of ordinary aggregate may make lightweight aggregate concrete, which possesses many advantages such as lightweight, lower thermal conductivity, and better fire and seismic resistance. Recently the developments of LWA have been focused on using industrial wastes as raw materials to reduce the use of limited natural resources. In view of this, the intent of this study was to apply Taguchi optimization technique in determining process condition for producing synthetic LWA by incorporating waste thin film transition liquid crystal displays (TFT-LCD) glass powder with reservoir sediments. In the study the waste TFT-LCD glass cullet was used as an additive. It was incorporated with reservoir sediments to produce LWA. Taguchi method with an orthogonal array L16(45) and five controllable 4-level factors (i.e., cullet content, preheat temperature, preheat time, sintering temperature, and sintering time) was adopted. Then, in order to optimize the selected parameters, the analysis of variance method was used to explore the effects of the experimental factors on the performances (particle density, water absorption, bloating ratio, and loss of ignition) of the produced LWA. The results showed that it is possible to produce high performance LWA by incorporating waste TFT-LCD glass cullet with reservoir sediments. Moreover, Taguchi method is a promising approach for optimizing process condition of synthetic LWA using recycled glass cullet and reservoir sediments and it significantly reduces the number of tests.

• 한국구조물진단유지관리공학회 논문집
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• 제15권5호
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• pp.209-217
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• 2011

최근 구조물들이 대형화됨으로써 보통 콘크리트를 사용할 경우 강도 및 내구성에 비하여 중량이 크다는 결점으로 인해 콘크리트 구조물의 설계 및 시공의 안정에 제약을 주게 된다. 이러한 결점을 개선하기 위해서는 자중이 작고 강도가 큰 경량콘크리트가 요구되나, 국내에서는 실용화를 위한 연구가 아직 미비한 실정에 있다. 일반적으로 고온에서 소성시켜 제조된 인공골재는 골재가 팽창되어 내부에 무수한 기포를 가지게 된다. 따라서 골재의 크기에 따라 이들의 기포가 경량콘크리트 비중과 강도에 미치는 영향 연구가 필요하다. 본 연구에서는 국내에서 개발된 화력발전소 폐기물과 점토를 고온에서 소성, 팽창시켜 만든 인공경량골재의 입도별 배합설계를 실시하고 실험을 통하여 경량콘크리트의 비중 및 강도변화를 비교 고찰했다. 또한 경량콘크리트의 고강도 발현을 위한 인공경량골재의 최적 입도비를 제안하였다.

• KCI Concrete Journal
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• 제14권3호
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• pp.121-129
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• 2002

This study investigates experimentally into the design factors and quality variations having an effect on the properties of the combined high flowing concrete to be poured in the slurry wall of Inchon LNG in-ground receiving terminal. Especially, high belite cement and lime stone powder as cementitious materials and viscosity agent in order to improve self-compaction and hydration heat are used in this study. Water-cement ratio(W/C), fine aggregate volume ratio(Sr) and coarse aggregate volume ratio(Gv) as design factors of the combined high flowing concrete are applied to determine the optimum mix design proportion. Also quality variations for sensitivity test are selected items as followings. (1)Surface moisture(5cases) and (2)Fineness modulus of fine aggregate(5cases), (3)Concrete temperature(3cases), (4)Specific surface(3cases) and particle size of lime stone powder. As experimental results, water-cement ratio, fine and coarse aggregate volume ratio are shown as the optimum range 51%, 43% and 53% separately considering site condition of slurry wall. Also quality factors by sensitivity test should be controlled in the following ranges. (1) Surface moisture :to.67% and (2)Fineness modulus 2.6$\pm$0.2 of fine aggregate, (3)Concrete temperature l0-20t, (4) Specific surface 6,000$\textrm{cm}^2$/g and particle size 9.7$\pm$1.0${\mu}{\textrm}{m}$ of lime stone powder. Based on the results of this study, the optimum mix design proportion of the combined high flowing concrete are selected and poured successfully in the slurry wall of LNG in-ground tank.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.281-286
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• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment of curing temperature $35^{\circ}C$, . Flesh concrete tested slump. air contest and Hardening concrete valuated setting period of form, day of age 1, 3, 5. 7, 10, 28 compression strength in sealing curing. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Experiment result age 28day compression strength more higher plan concrete then standard environment in curing temperature $20^{\circ}C$, , most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$, replacement binder 25%, fine aggregate 15%. (2) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.131-132
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• 2017

As the building is becomes bigger and larger, it can lead to big damage in case of fire. Also, tunnel, machine room and underground joint are spaces that can cause high temperature fire above 1,350℃ in case of fire. Therefore, a refractory material is need that can be withstand in high temperatures for long time. One side, the composition of oyster shell is CaCO₃ of 90% or more. It is expected that it will be possible to use it as a high calcium natural material which is the material of the refractory board. According to, Study on bending, compressive strength of mortar according to temperature and heating time change using oyster shell as aggregate the most commonly occurring particle sizes form 2.5mm to 5mm.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.122-123
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• 2017

As the building is becomes bigger and larger, it can lead to big damage in case of fire. Also, tunnel, machine room and underground joint are spaces that can cause high temperature fire above 1,350℃ in case of fire. Therefore, a refractory material is need that can be withstand in high temperatures for long time. One side, the composition of oyster shell is CaCO₃ of 90% or more. It is expected that it will be possible to use it as a high calcium natural material which is the material of the refractory board. According to, Study on bending, compressive strength of mortar according to temperature and heating time change using classified oyster shell as aggregate.

• 콘크리트학회논문집
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• 제28권4호
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• pp.445-454
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• 2016

노후 시설물의 증가에 따라 건설폐기물은 일정 수준까지 증가한 이후, 현재는 어느 정도 안정화 된 추세에 있지만, 전체폐기물 중에서 건설폐기물은 아직까지도 가장 큰 비중을 차지하고 있다. 또한, 천연 골재 채취 금지에 의한 골재 난 심화 및 골재 공급원 개발에 의한 국토훼손과 자연환경 파괴 등에 따라 환경복원에 막대한 국가예산 소요가 불가피한 상황이다. 이에 대한 대책 방안으로 국토교통부는 순환 골재 품질기준을 공포하여 순환 골재 품질에 따른 용도와 관리를 할 수 있도록 추진하고 있으나, 경제적 부가가치가 높은 용도로의 활용은 아직 저조한 실정이다. 따라서, 본 연구에서는 저자의 선행연구에서 제시한 탄산화 개질 조건인 $20^{\circ}C$, RH 60%, $CO_2$ 20%에서 순환 잔골재 4일, 순환 굵은 골재 14일간 탄산화를 실시한 순환 골재의 품질개선효과 및 이를 이용한 순환 골재 콘크리트의 성능 평가를 통하여 구조용 콘크리트로의 적용 가능성에 대한 실마리를 찾고자 한다. 그 결과, 탄산화 개질을 통하여 순환 잔골재의 흡수율이 0.91%, 순환 굵은 골재의 흡수율이 0.7% 저감되어 품질개선에 기여하였다. 또한, 탄산화 개질 골재를 이용한 순환 골재 콘크리트의 물리적 특성 및 내구성능이 일반 콘크리트와 유사한 결과를 나타내어 구조용 콘크리트로의 적용 가능성을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.91-92
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• 2013

The strength of ultra-high-strength concrete can be reduced even if the spalling is prevented at a high temperature. Therefore, in this study, we measured internal temperature history and residual compressive strength using a 300×300×450mm short column specimens which use the fiber(NY 0.15+PP 0.10+SF 0.30vol·%) and respectively silica sand, washed sand, the slag sand. As a result, the temperature history and residual compressive strength are almost similar regardless of the fine aggregate types.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.235-236
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• 2021

This study evaluated temperature distribution through adiabatic temperature rising test and hydration heat Analysis as a performance verification to utilize CGS as a hydration heat reduction material for mass concrete when replacing it with fine aggregate. According to the analysis, the temperature difference between the center and the surface was the highest at about 30℃, followed by the CGS 50% at 26℃ and the low heat combiner FA 30% at 23℃.