수밀성 재료에 의한 숏크리트의 수밀성에 관한 연구

강현주,송명신,이상국,Kang, Hyun-Ju,Song, Myong-Shin,Lee, Sang-Kook 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.6

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.

내구성 향상을 위하여 단열성능이 부여된 단면복구 MORTAR의 물성

강현주,나승현,송명신,정의담,서병돌,Kang, Hyun-Ju,Na, Seung-Hyun,Song, Myong-Shin,Jeong, Eui-Dam,Seo, Byung-Dol 한국세라믹학회 2010 한국세라믹학회지 Vol.47 No.5

In this study, we studied on the durability of restorative cement mortar for deteriorated concrete at complex deteriorated conditions as variation of temperature and of humidities. We made a comparison between restorative materials with insulation function and restorative materials without insulation function in items of compressive and bending strength and permeability of water, durability for carbonation, salt damage, diffusion coefficient of salt at complex deterioration conditions like change of temperature, change of humidity, For insulation, we used close-pore type Alumino-Silicate lightweight aggregate and substituted 12 wt% and 15 wt% out of original restorative cement mortar without insulation function. As a result, it was found that original restorative cement mortar without insulation function fail to meet Korean Standard on polymer modified cement mortar for maintenance in concrete structure, but restorative cement mortar with insulation function is in contentment Korean Standard to meet excellent than restorative materials without insulation function for durability at complex deteriorated conditions.

pH 변화에 따른 고로수쇄 BFS의 초기 수화 특성

강현주,이웅걸,송명신,강승민,김경남,Kang, Hyun Ju,Lee, Woong Geol,Song, Myong Shin,Kang, Seung Min,Kim, Kyeng Nam 한국세라믹학회 2012 한국세라믹학회지 Vol.49 No.5

This study investigated on the early hydration and physical characteristics of BFS by pH variation. NaOH solution was used as a pH activator. In the range from pH 12 to pH 14, Experiment was compared the hydration propertied of OPC(Ordinary Portland Cement) and BFS(Blast Furnace BFS) and BFS containing 2 wt% of gypsum. It was found that CAH(Calcium Aluminate Hydrates) phases and CSH(Calcium Silicate Hydrates) phases were formed during the early hydration of BFS, and that CAH phases, CSH phases and ettringites were formed during the early hydration of BFS containing 2 wt% of gypsum. Furthermore, early hydration of BFS and BFS containing 2 wt% of gypsum were faster then OPC at pH 14, and the 1 day compressive strength of BFS increased by approximately 30% compared to OPC, and BFS containing 2 wt% of gypsum also increased by approximately 40% compared to OPC.

해수 콘크리트에 대한 수중불분리 혼화제와 방청제의 효과에 관한 연구

강현주,이경희,조인성,한형섭,Kang, Hyun-Ju,Lee, Kyung-Hee,Cho, In-Sung,Han, Sub-Hyung 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.10

본 논문에서는 수중불분리혼화제와 수중불분리혼화제+방청제를 병용(1 type)한 혼화제를 사용하여 콘크리트의 slump flow, 탁도, pH, 방청효과, 블리딩, 압축강도의 특성을 분석하였다. 그 결과 slump flow, 탁도, pH, 압축강도등 콘크리트의 물리적인 특성에서는 차이가 없었으나 부식촉진서험결과 수중불분리혼화제만을 사용한 콘크리트와 방청제를 병용(1 type)하여 사용한 것의 방청율이 큰 차이를 나타내었으며, 수중불분리혼화제만을 사용하였을 경우 5.4, 방청제와 병용하여 사용하였을 경우 0.07%로 방청제를 병용(1 type)하여 사용한 큰크리트의 내부식성이 높게 나타났다. In this paper, the slump flow of the concrete, suspension, pH, corrosion effect, bleeding and the characteristics of coompressive strength were analyzed using antiwashout underwater admixture and antiwashout underwater agent+corrosion inhibitor mixed admixtures(1type). The results showed that there were no rare difference in physical properties but in the results of rapid corrosion tests there were lots of corrosion inhibitor ratio differences between concrete using only antiwashout underwater admixture and the corrosion inhibitor mixed(1type). In the case of only antiwashout underwater admixture 5.4%, the case corrosion inhibitor mixed(1type) 0.07%, the Antiseawater of the concrete which uses the Corrosion Inibitor Mixed(1type) appeared highly.

수중불분리콘크리트에 사용되는 멜라민유동화제 개발

강현주,이경희,조인성,박의순,Kang, Hyun-Ju,Lee, Kyung-Hee,Cho, In-Sung,Park, Soon-Eui 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.10

본 연구에서는 수중불분리혼화제로서 메칠셀룰로스계를 사용하였고 자체 개발한 멜라민유동화제의 수중불분리콘크리트에 대한 사용량을 5, 7, 9, 11 kg/$m^3$으로 첨가량을 달리하여 slump folw, flow loss, 응결사간, 탁도 및 pH, 압축강도, 수중/기중 압축강도비를 실험한 결과 수중불분리콘크리트의 물성이나 경제성등을 고려할 때 수중불분리콘크리트에서의 멜라민유동화제의 사용량은 약 9 kg/$m^3$인 것으로 나타났다. In this studies, methly celluloes was used as antiwashout admixture and when considering the physical properties and economical efficiencies of Underwater Concrete as the results of making an experiencing slump flow, flow loss, setting time, suspension and pH also compressive strength and underwater/an air compressive strength ratio according to the adding amount changes 5, 7, 9, 11 kg/$m^3$ to Underwater Concrete of melamine superplasticizer, the using amount of melamine superplasticizer in Underwater Concrete approximately represents 9 kg/$m^3$.

시멘트의 수화특성에 대한 유·무기 복합 나노실리카의 영향

강현주,송명신,박종헌,송수재,Kang, Hyun-Ju,Song, Myong-Shin,Park, Jong-Hun,Song, Su-Jae 한국세라믹학회 2011 한국세라믹학회지 Vol.48 No.6

In this study, as a material used to replace silica fumes for high strength concrete, nano-silica compound with organic functional group for dispersion and with inorganic silica group that can cause a pozzolan reaction is synthesized, These nano silica compound is divided into IC, which is nano size $SiO_2$ with irregularly combined hydroxyl group and carboxyl group, and RC, which is nano size $SiO_2$ with regularly combined hydroxyl group and carboxyl group. The effects of these nano silica compound on the hydration of cement are reviewed. As a result, all of synthesized nano-silica compounds have excellent dispersion on the cement flow, we think that dispersion property is the effect of air entraining by synthesized nano-silica compounds. The result of the microstructure observation showed that the particle size of the synthesized nano-silica is smaller than silica fume and spread evenly among the cement particles. In initial The phenomenon of strength decreasing occurred due to delayed hydration reaction by the synthesized nano-silica with carboxyl(-COOH) and hydroxyl(-OH) functional group.

고성능 감수제 종류에 따른 실리카흄이 혼입된 시멘트 수화 특성

강현주,송명신,박종헌,송수재,Kang, Hyun-Ju,Song, Myong-Shin,Park, Jong-Hun,Song, Su-Jae 한국세라믹학회 2011 한국세라믹학회지 Vol.48 No.6

In this study, the effect of superplasticizers on the dispersibility and hydration properties of cement with silica fume were investigated. Superplasticizers are used Naphthalene type, Ligno-sulfate type and polycarboxylate type. Compared with plastic viscosity of cement paste without superplasticizers(Plain), plastic viscosity of cement paste with superplasticizers are reduced and yield stress of cement pastes with each superplasticizer is increased rather than Plain. And then, plastic viscosity of cement paste with Naphthalene type superplasticizer was the least of all types. Compared with other two types, setting and hydration of cement paste with Polycarboxylate type(PC) superplasticizer is very fast. At compressive strength after 3-day, PC is higher than other two types, But, compressive strength of after 7-day and 28-day, PC is smaller than other two types.

네트워크 가상화 기술 동향

강현주,박혜숙,안병준,이순석,Kang, H.J.,Park, H.S.,Ahn, B.J.,Lee, S.S. 한국전자통신연구원 2010 전자통신동향분석 Vol.25 No.6

네트워크 가상화가 과거 공중망을 사설망으로 사용할 수 있도록 가상화시켜 보안성과 함께 망을 분리하는 개념으로 쓰이다가 최근 클라우드 컴퓨팅과 미래 인터넷 기술의 등장으로 모든 자원을 가상화하여 사용자들에게는 편의를, 비즈니스 측면에서는 인프라와 서비스 제공자의 분리를 통한 새로운 마켓 창출을 위한 주요한 기술로 요구되고 있다. 이에 띠라, 본 고에서는 현재까지 기상 네트워크망에서 각 서비스 기술이 요구하는 가상화와 네트워크 가상화에 대해 알아보고 통신 장비를 개발하는 입장에서 네트워크 가상화를 위해 진행되는 일과 앞으로 진행될 방향을 다룬다.

청소년의 건강행태와 구강 증상과의 융합적 관련성

강현주,Kang, Hyun-Joo 한국융합학회 2020 한국융합학회논문지 Vol.11 No.9

The purpose of this study was to provide data on the development of educational programs to maintain oral health in adolescence by identifying the relevance of health behavior and symptom to adolescents. The subjects of this study were 27,919 high school students' using the 15th (2019) Youth Health Behavior Online Survey. The logistic regression analysis was used to identify the factors influencing oral symptoms. The results showed that the recognition of gingiva pain was significantly lower in the subjects with male sex, lower education level, higher income level, and higher subjective perception of oral health. Higher the stress, higher the pain recognition, revealing a statistical significance. The awareness on bad breath-related symptoms was significantly higher in the adolescents with male sex, higher degree of stress, and lower frequency of daily toothbrushing. The lower awareness on halitosis was associated with higher income and higher subjective perception of oral health, showing a statistical significance. This study found that the health behavior of adolescents had an effect on their oral symptoms and the finding is expected to help develop programs for preventing those oral symptoms. 본 연구는 청소년의 건강행태와 증상의 관련성을 파악하여 청소년기의 구강건강을 유지하기 위한 교육 프로그램 개발에 관한 자료를 제공하는데 목적이 있다. 제15차(2019년) 청소년건강행태온라인 조사자료를 이용하여 고등학생 27,919명을 대상으로 하였다. 구강 증상에 미치는 영향요인을 로지스틱 회귀분석한 결과 잇몸 통증 증상을 낮게 인지한 경우는 남자, 저학년, 소득수준이 높은 경우, 주관적 구강건강 인지가 매우 좋은 경우 유의하게 낮았다. 스트레스가 높은 경우는 통증 인지가 높아 통계적으로 유의했다. 구취 증상을 높게 인지한 경우로는 남자, 스트레스가 높은 경우, 1일 잇솔질 실천 횟수가 적은 경우 유의하게 높았다. 소득이 높은 경우, 주관적 구강건강 인지가 매우 좋은 경우에는 구취 인지가 낮아 통계적으로 유의했다. 본 연구는 청소년의 건강행태가 구강 증상에 영향 미치는 것을 알 수 있었고, 이러한 구강 증상을 예방할 수 있는 교육 프로그램 개발에 도움을 주고자 한다.

구체방수제가 혼입된 시멘트 경화체의 방수 메카니즘

강현주,송명신,박종헌,전세훈,이성현,Kang, Hyun Ju,Song, Myong Shin,Park, Jong Hun,Jeon, Se Hoon,Lee, Sung Hyun 한국세라믹학회 2013 한국세라믹학회지 Vol.50 No.1

The pore volume of hardened cement with waterproofing materials is lower compared to that of hardened cement without waterproofing materials. Thus, fewer gaps will appear by means of chemical reactions between $Ca^{2+}$ ions in hardened cement and water, solutes, and other ions. Due to the selective permeability, the osmotic pressure of hardened cement can change due to physical effects such as the reduction of the pore volume and the reduction in the number of pores, as well as by the electrochemical reaction between water, solutes, other ions and $Ca^{2+}$ ions in hardened cement. Of course, these factors do not have independent effects but instead a combined complex effect. Accordingly, we studied changes in the osmotic pressure due to the difference in the pore structure of hardened cement. A pore size smaller than 1 nm in hardened cement had only a slight effect on the osmotic pressure, whereas a pore size larger than 1 nm had a direct effect on the osmotic pressure.