• 한국세라믹학회지
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• 제45권6호
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• pp.350-357
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• 2008

The use of shotcrete-sprayed concrete for the support of underground excavations was pioneered by the civil engineering. Now, for the nuclear wastes disposal plant in our country, watertightness of shotcrete is one of the very important properties. This study evaluated the watertightness of shotcrete using cement mineral accelerator with watertightness materials for the long-term watertightness. In this study, for improvement of watertightness of shotcrete, it used two types of obtainable at a store. Watertightness tests of shotcrete were performed the water absorption coefficient, permeability, porosity and hydrates variation. In a shotcrete containing watertightness materials, watertightness of shotcrete was improved about $15%{\sim}65%$ rather than plain shotcrete.

• 한국방재학회 논문집
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• 제10권5호
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• pp.17-25
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• 2010

콘크리트의 내구성능 향상을 위한 방안으로서 시멘트 재료의 수밀성능 증진에 대한 연구를 수행하였다. 보통 포틀랜드 시멘트 및 보통 포틀랜드 시멘트와 플라이애쉬의 혼합계 재료에 다양한 성능의 수밀성능 개선제를 혼합하여 수밀성 실험을 진행한 결과, 시멘트 재료의 수밀성능 향상은 시멘트 수화생성물인 CSH의 생성과 유기지방산에 의한 수화물과의 접촉각의 크기와 밀접한 관계가 있으며 수화초기에 활발하게 생성되는 CSH는 수밀성과 장기적인 흡수율 저감에 영향을 주는 것으로 나타났다. 또한 시멘트 재료의 작업성 개선을 위하여 플라이애쉬를 사용하는 경우, 구형 플라이애쉬의 작업성 증진에 의해 시멘트 재료의 조직이 치밀화 되고 포졸란 재료의 특성에 의한 CSH의 생성으로도 수밀성이 향상 되는 것으로 나타났다. 다양한 종류의 수밀성 재료를 혼합하여 흡수율 및 수화 생성물의 변화에 대해 실험한 결과, 콘크리트의 내구성 향상을 위해서는 어떠한 형태이든 시멘트 재료에 수밀성 혼화제의 혼합 사용이 바람직 한 것으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2010년도 춘계 학술논문 발표대회 1부
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• pp.13-16
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• 2010

This study is an Investigation on the Watertightness Properties of Rain-Block System on the Sliding-Roof Joint of Large-Span Membrane Structures. In this experimental, we test the watertightness performance of joint part of sliding door in roof of large span membrane structure(for pilot project) under environment of rain and wind. A shape of rain water blocking systems of joint part in sliding door verifies the defects and effects of water leakage prevention in precipitation with the wind conditions. For obtaining watertightness of large span membrane structures, it is necessary quality of joints and performance, and quality of membrane material of a retractable roof as well as a closed roof. Also, for obtaining quality in joints, it is essential to make a watertightness guideline for design of large-span membrane.

• 한국세라믹학회지
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• 제46권4호
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• pp.365-371
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• 2009

It is well known that the properties of concrete such as the compressive strength, water permeability, water tightness and durability are affected by micro-structure in hardened cement paste. Especially, for durability of concrete, watertightness of cementitious materials is the most critical property among various properties. Recently, many types of materials as organic and/or inorganic materials are used for watertightness of concrete. In this study, The effect of Stearic Acid at $0.5\;wt%{\sim}3.0\;wt%$ adding ratios on the hydration and watertightness property of cement were investigated. And we also discussed the changing of microstructure in hardened cement paste by addition of Stearic Acid. Cement paste with Stearic Acid showed improvement of watertightness by reducing of cement total pore volume and decomposition of Stearic Acid.

• 콘크리트학회논문집
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• 제12권3호
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• pp.39-46
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• 2000

This study is to investigate the watertightness properties of waterproofing admixture mixed redispersible polymer and siliceous powder. Series I deals with change in micro-structure of mortar by waterproofing admixture according to the water/cement ratios of 0.5, 0.6, 0.7 and 0.8 Crystal growth in micro-structure was observed through SEM to estimate on the watertightness effect of it. SeriesII deals with watertightness properties of waterproofing admixture on water permeability coefficient, crack restoration capacity and carbonation depth. SeriesII deals with watertightness properties of waterproofing admixture on water permeability coefficient, crack restoration capacity and carbonation depth. The result of this study can be summarized as follows. 1) Fluidity of mortar and concrete was increased by adding waterproofing admixture. 2) From observation through SEM. Crystals grew larger and denser in micro-structure as fiberic crystalization. 3) Waterproofing admixture is good watertightness properties in a level of high water/cement ratios and long limit of time. 4) Crack restoration capacity was appeared and durability was progressed by waterproofing admixture.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술대회지
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• pp.33-38
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• 2004

This study was performed to know watertightness and reduction effect and crack occurred by hydration heat, restraint of multiplication of hydration heat, through mechanical test, strength test and crack control test using fluosilicate salt based inorganic compound made from by-product during phosphoric acid manufacturing process. Mix proportions for experiment were modulated at 0.45 of water to cement ratio and $0.5-2.0\%$ of adding ratio of fluosilicate salt based inorganic compound. Evaluation for watertightness of concrete was carried out permeability, absorption test and porosity analysis. Effect of crack reduction was evaluated by length, drying shrinkage as well as stress change of hardened concrete at unrestraint/restraint state and also elucidated crack pattern on the concrete surface. It is ascertained that characteristics of crack resistance and watertightness for concrete was improved by an adequate addition of fluosilicate salt based inorganic compound.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.36-39
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• 2004

In this study, effects of fluosilicate salt based chemical admixture(MZ) on the watertightness and hardening properties of concrete were investigated. Mix proportions for experiment were modulated at 0.55 of water to cement ratio and addition amount of MZ to $2.0\%$ at intervals $0.5\%$. Compressive strength, porosity and microstructure of hardened concrete cured at several days were executed to evaluate watertightness and hardening properties. It is ascertained that watertightness and hardening properties of concrete could be improved by an adequate addition of fluosilicate salt based chemical admixture.

• 공업화학
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• 제20권5호
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• pp.505-510
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• 2009

콘크리트의 내구성에 대한 대표적인 물리적 특성인 압축강도, 투수성능, 수밀성 등은 시멘트 재료의 미세구조에 의해 영향을 받는다. 특히 콘크리트의 내구성 향상을 위해서는 수밀성이 가장 중요하다 할 수 있다. 콘크리트의 수밀성 향상을 위한 재료는 유기 재료 및 무기질 재료가 다양하게 이용이 되고 있다. 본 연구에서는 불소계 에멀젼이 시멘트 수밀성능에 미치는 영향을 검토하였다. 불소계 에멀젼이 혼입된 시멘트 재료는 시멘트 계면 활성에 의한 수밀성능 개선 및 시멘트 pore 내에서 $CaF_2$ 미세 결정의 생성에 의해 시멘트 재료의 수밀성능을 개선시킬 수 있는 것으로 나타났다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술논문발표회
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• pp.81-84
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• 2002

Recently Bentonite mat is applied various structure : External waterproofing for underground structure, A reclaimed land, Artificial lake, Large-scaled civil structure, etc. With these various structure environment, water quality for application of Bentonite Mat affects watertightness. Specially spot with a large quantity of Chloride ion like salt water, degree of watertightness revelation is evaluated and applied. In this study, it is a main goal to investigate watertightness of Bentonite Mat with distilled water and salt water dissolved chloride ion Contents 0.88%. The result of this paper is as follows. 1) Water permeability coefficient of Bentonite Mat : distilled water(1.21$\times$10$^{-9}$cm/sec), salt water(3.12$\times$10$^{-7}$cm/sec). 2) Variation of thickness : distilled water(187%), salt water(108%). 3) Swelling ratio : distilled water(1500%), salt water(350%).

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.617-620
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• 2006

This study is related to comprehending performance for watertightness and crack control of concrete added with crack reducing agent concerning to high strength concrete mixs. It was confirmed that watertightness of concrete added with agent could be improved by evaluation absorption ratio, permeability ratio and pore size distribution of hardened concrete. As well resistance to crack resulted from shrinkage was transferred to better state by the addition of agent.