• 공학논문집
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• 제8권1호
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• pp.31-50
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• 2006

수축은 콘크리트에 균열을 발생시키는 경우도 있다. 일반적 조건하에서는 콘크리트의 건조를 피할 수 없으며 건조가 일어나면 수축이 생기므로 대부분의 콘크리트 적용분야에서는 실제로 이와 같이 균열발생을 고려하여야 한다. 균열이 발생한 콘크리트는 균열이 없는 콘크리트에 비하여 강도가 약하고 투과성이 크며 화학적 침식의 영향을 받기 쉽다. 또 재령의 경과에 따라 경량기포콘크리트의 강도발현은 기포제의 종류, 물과 시멘트와의 비, 양생조건 및 기간 등과 같은 인자에 의존하고 있다. 경량기포콘크리트의 강도가 높으면 높을수록 수축에 의하여 균열이 발생할 가능성이 감소한다. 그러므로 온돌구조용으로의 경량기포콘크리트의 강도는 소포율과 시멘트의 건조수축과의 균열저감효과에 크게 의존된다.

• 한국지반공학회논문집
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• 제22권7호
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• pp.73-83
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• 2006

조립토 다짐말뚝의 거동특성은 주로 말뚝의 횡방향 팽창을 억제하는 연약한 원지반의 횡방향 구속응력에 의해 지배된다. 따라서 조립토 다짐말뚝의 지반 보강 능력은 원지반의 비배수 전단강도가 $15{\sim}50kPa$ 정도인 경우에 가장 효과적인 것으로 알려지고 있으며, 보다 연약한 지반에서는 구속압력이 충분하게 발휘되지 않으므로 적용성이 크게 저하된다. 본 연구에서는 연약지반에 대한 조립토 다짐말뚝의 적용성 확대를 위해 등입도 투수성 콘크리트 보강 조립토 다짐말뚝 공법을 제안하였으며, 등입도 투수성 콘크리트와 쇄석 및 연약 점성토로 구성된 복합 공시체의 대형삼축압축시험을 통해 제안된 공법의 효율성을 입증하였다. 또한 본 연구에서는 제안된 공법의 실무 적용성 확보를 위해 침하량 산정기법을 제안하였으며, 제안된 침하량 산정기법의 검증을 위한 목적으로 3차원 유한요소해석을 실시하여 해석결과로 분석된 말뚝의 침하량과 제안식에 의해 산출된 침하량을 상호 비교 분석하였다. 추가적으로 본 연구에서는 다양한 변수분석을 수행하여 설계변수의 영향정도를 평가하였다.

• 한국건축시공학회지
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• 제9권1호
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• pp.49-55
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• 2009

In this study, reduction methods of surface air void were examined for high performance concrete having high viscosity. The effects of assumed influencing factors such as form types, form-coating materials, tamping equipments and methods were examined based on the tests on mock-up specimens made of high performance concrete. The test results can be summarized as follows: As for form types, the most favorable results were obtained when coated plywood form was used with panel-shape tamping equipments at the contact region with concrete, the second and the third being the water/air-permeable sheets and steel with coated plywood, respectively. As for tamping equipments, a vibrator with 6.5cm diameter was most effective. Finally, the shorter the tamping intervals, the better the reduction effect of surface air void. As a conclusion, an improved method was proposed to reduce surface air void and it was verified with the test result that only four air voids as large as $5{\sim}10mm$ are found in the are of $1m^2$.

• 기술사
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• 제42권3호
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• pp.47-53
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• 2009

Riverbed filtration(RBF) system is used to develop ground water and infiltrated water supplies from permeable sand and gravel deposits. RBF plants are constructed with a reinforced concrete caisson that serves as a wet well pumping station. The lateral well screens are projected horizontally into waterbearing deposits from inside the caisson. Riverbed filtration(RBF) is a low-cost and efficient alternative water treatment for drinking-water applications.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2001년도 춘계학술대회 발표논문집
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• pp.236-240
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• 2001

본 연구는 제철소에서 부산물로 생성되는 고로슬래그 및 제강슬래그를 골재의 일부로 대체 사용하고 고성능AE감수제를 적정량 사용하여 고품질의 투수성 콘크리트를 제조하는 것에 관한 것이다. 실험결과 고성능AE감수제와 슬래그를 사용하는 경우 투수계수 0.1cm/sec 이상을 유지하는 상태에서 재령 28일의 압축강도 240kgf/㎠ 정도까지의 비교적 높은 강도의 투수성 콘크리트를 경제적으로 제조할 수 있음이 확인되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.227-233
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• 2008

Porous concrete has large continuous voids of 20-30 % by volume, and this concrete is attractive as environmental material in Japan i.e. permeable road pavement, river bank protection with vegetation and green roof system which influence thermal environment. It is necessary to confirm the frost resistance when constructing porous concrete structure in cold region. However applicable test method and evaluation criterion of porous concrete has not defined yet. Therefore, the object of this study is to investigate the frost resistance of porous concrete and this investigation attempts to address this concern by comparing 4 kinds of specified freezing and thawing tests methods (JIS A1148 procedure A/B and RILEM CIF/CDF test) in consideration of actual environment. RILEM freeze-thaw tests are different from JIS A1148 freeze-thaw tests, which are widely adopted for evaluating the frost resistance of conventional concrete in Japan, in water absorption, cooling rate, length of freezing and thawing period, and number of freezing and thawing cycles. RILEM CIF test measures internal damage and is primarily applicable for pure frost attack. CDF test is appropriate for freeze-thaw and de-icing salt attack. JIS A1148 procedure A/B showed extremely low frost resistance of porous concrete if the large continuous voids were filled with water and the ice expansion in the large continuous voids set in during cooling. Frost resistance of porous concrete was improved by mixing coarse aggregate (G7) which particle size is smaller and fine aggregate in JIS freezing and thawing tests. RILEM CIF/CDF test showed that freeze-thaw and de-icing resistance of porous concrete was seems to be superior in that of conventional concrete.

• Advances in concrete construction
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• 제10권2호
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• pp.127-140
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• 2020

This study explores the feasibility of granite waste aggregate (GWA) as a partial replacement of natural fine aggregate (NFA) in binary blend self-compacting concrete (SCC) prepared with fly ash. Total of nine SCC mixtures were prepared wherein one was Ordinary Portland cement (OPC) based control SCC mixture and remaining were fly ash based binary blend SCC mixtures which included the various percentages of GWA. Fresh properties tests such as slump flow, T₅₀₀, V-funnel, J-ring, L-box, U-box, segregation resistance, bleeding, fresh density, and loss of slump flow (with time) were conducted. Compressive strength and percentage of permeable voids were evaluated in the hardened state. All the SCC mixtures exhibited sufficient flowability, passing ability, and resistance to segregation. Besides, all the binary blend SCC mixtures exhibited lower fresh density and bleeding, and better residual slump (up to 50% of GWA) compared to the OPC based control SCC mixture. Binary blend SCC mixture incorporating up to 40% GWA provided higher compressive strength than binary blend control SCC mixture. The findings of this study encourage the utilization of GWA in the development of binary blend SCC mixtures with satisfactory workability characteristics as a replacement of NFA.

• 한국농공학회논문집
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• 제49권4호
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• pp.51-59
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• 2007

Recently, concrete has been made porous and used for sound absorption, water permeation, vegetation and water purification according to void characteristics. Many studies are carried out on the utilization of sewage sludge, fly ash and waste concrete to reduce the environmental load. This study was performed to evaluate the void, strength, relationship between void and strength, permeability and chemical resistance properties of porous polymer concrete for pavement with different fillers. An unsaturated polyester resin was used as a binder, crushed stone and natural sand were used as an aggregate and bottom ash, fly ash and blast furnace slag were used as fillers. The mix proportions were determined to satisfy the requirement for the permeability coefficient, $1{\times}10^{-2}$ cm/s for general permeable cement concrete pavement in Korea. The void ratios of porous polymer concrete with fillers were in the range of $18{\sim}23%$. The compressive strength and flexural load of porous polymer concrete with fillers were in the range of $19{\sim}22$ MPa and $18{\sim}24$ KN, respectively. The permeability coefficients of porous polymer concrete with fillers were in the range of $5.5{\times}10^{-1}{\sim}9.7{\times}10^{-2}$ cm/s. At the sulfuric acid resistance, the weight reduction ratios of porous polymer concrete immersed during 8-week in 5% $H_{2}SO_{4}$ were in the range of $1.08{\sim}3.56%$.

• 한국건축시공학회지
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• 제9권5호
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• pp.71-77
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• 2009

시멘트 혼화용 폴리머 디스퍼션은 시멘트 모르타르 및 콘크리트 내부에서 폴리머 필림을 형성하여 각종 역학적성 질 및 내구성을 향상시킨다. 본 연구는 3종류의 폴리머 디스퍼션을 폴리머 시멘트비 0, 5, 10, 20%로 변환한 폴리머 시멘트 모르타르를 제작, 투수시험을 실시하여 투수성능을 실험하였으며, 더욱이 폴리머 시멘트 슬러리를 폴리머 시멘트 모르타르 표면에 도포하여 방수성능의 개선효과를 평가하였다. 또한 보통시멘트 콘크리트 표면에 폴리머 시멘트 슬러리를 도포하여 시멘트 콘크리트와 폴리머 시멘트 슬러리의 건조수축을 측정하였다. 그리고 기본적인 역학적 성상인 휨강도와 압축강도를 측정하여 보통 시멘트 모르타르와 비교 검토하였다. 연구결과, 폴리머 시멘트 모르타르는 보통 시멘트 모르타르에 비해 방수성능과 강도가 크게 개선되었으며, 폴리머 시멘트 슬러리의 건조수축은 시멘트 콘크리트에 비해 4-5배 크게 나타났다. 또한 향후 건조수축에 따른 접착성능의 영향성에 대한 연구가 진행되어야 할 것이다.

• 한국물환경학회지
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• 제34권3호
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• pp.293-300
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• 2018

Ihe purpose of this study is to evaluate the effects the storage type of permeable concrete block paving (ST-PCBP) have on runoff reduction and infiltration increasement at Andong Maskdance Festival Square. This was accomplished using the NRCS-curve number method over the last 10 years. Two different scenarios were developed in this study for low impact development (LID) design. For the $1^{st}$ scenario, the walking path and parking lot were install using the ST-PCBP and runoff from the inline skating rink ($3,808m^2$) and lawn ($11,191m^2$) were routed to the ST-PCBP, but the rooftop runoff flowed into the storm water drainage system. For the $2^{nd}$ scenario, one of the non-structural BMPs, disconnected impervious surface (DIS), was applied so additional runoff from rooftop would enter the ST-PCBP. It was determined that ST-PCBP could significantly reduce surface runoff from the study area and increase infiltration with 71% and 88% of surface runoff reduction and 151% and 215% of infiltration increasement for scenarios 1 and 2, respectively. The effect of LID in the $2^{nd}$ scenario was better than the $1^{st}$ scenario, therefore DIS in conjunction with ST-PCBP could be a more cost-effective LID application.