• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.285-291
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• 1998

During recent years, the durability of concrete structures has been considered in concret practice and material research. To preserve the brittleness of concrete as well as energy absorption and impact resistance, amount of fiber usage has greatly increased in the field of public works. Ultra fine powder, silica fume, mixed into concrete, it reduce void of concrete structure. Especially, there's a great effect for strength improvement of concrete by initial pozzolanic reactions. For these reasons, if silica fume mixed into concrete, it decrease the total void by microfilter effect . Pozzolan reaction, between cement particle and silica powder, can elaborate the micro structure of matrix. And so, in this paper, we deal SFRC for the purpose of efficiently using of industrial by-products(silica fume). Also we performed the test for durability such as freeze-thaw resistance and accelerated carbonation of SFRC using silica fume.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1361-1366
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• 2009

This study is to see the internal flow for the plasma cutting fume collector. Plasma cutters are widely used in the canning industry and Fume cause the device because it will affect the performance of the design of dust collector. Therefore, to determine the distribution of the internal flow using CFD and Solver was used for calculated with commercial CFD code STAR-CCM+. The results show that design of chamber was incorrect after passed the filter for exhaust to the fan. And the location of the duct to the influx of dust collector and the design was incorrect. In addition, an array of filter was also inappropriate. As a result, present fume collector need to improvement.

• 한국농공학회지
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• 제39권1호
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• pp.83-92
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• 1997

An experimental study of the application of Silica fume for the high strength concrete was conducted. Nine specimens with three different contents of silica fume, 0%, 10%, 20% and with three water-cement ratio 30%, 40%, 50% were tested. Results shows that 10% of silica fume and 30% of water-cement ratio has a maximum strength with 700kg/$cm^2$ of compressive strength and 64kg/$cm^2$ of splitting tensile strength and 100kg/$cm^2$ of flexural strength. Slump value of the tested samples decreases with increasing water-cement ratio and elapsed time of silica fume. Splitting tensile strength$({\sigma}_f)$ and flexural strength $({\sigma}_f)$ and static modulus of elasticity(E) can be correlated with compressive strength $({\sigma}_c)$ from a regression analysis.

• Journal of Welding and Joining
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• 제1권2호
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• pp.1-6
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• 1983

용접중 발생되는 흄(Fume) 및 가스는 용접작업 환경을 오염시킬 뿐만 아니라 인체에 매우 유해하다. 용접 흄(Fume)은 금속 산화물로 구성된 아주 작은 입자이며 가스는 일반적으로 CO, CO$_{2}$, NO$_{x}$, SO$_{x}$, XF 등으로 구성되어 있다. 일반 피복 아아크 용접봉에서 발생되는 용접 흄은 인체에 매우 해로운 영향을 미친다. 즉 다량 흡입하게 되면 두통, 발열 등 급성 증상이 발생한다. 또한 소량을 장시간 흡입해도 진폐 등 만성증상을 일으킨다. 그러므로 현 국내 용접장에서는 흄에 의한 장해 방지를 위하여 충분한 환기시설과 완벽한 보호구 착용, 그리고, 용접 재료 자체의 흄 발생량을 감소시킨 저흄 용접봉(low fume type electrode)의 사용 방법 등이 검토 실시되고 있다. 본 보고서에서는 흄에 대한 올바른 인식을 꾀하는 한편, 용접자의 건강 보호를 목적으로 개발된 조선 및 철구조물의 주요 용접 재료인 철분 산화철계 저흄 용접봉에 관하여 소개하고자 한다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.185-186
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• 2023

In the production of high-strength concrete of 80 MPa or more, silica fume is widely used as a binder to ensure the strength safety and pumpability of concrete. The bulk density of silica fume is an important physical property that can have a significant impact on the performance of concrete. Therefore, Understanding the effect of silica fume density on the physical properties of concrete and selecting the appropriate material with the correct density is crucial to ensuring optimal performance in construction projects.

• 도시과학
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• 제12권2호
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• pp.13-18
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• 2023

This study investigates the effect of polyvinyl alcohol (PVA) fiber and silica fume addition on the chloride penetration resistance of alkali-activated slag. Silica fume was added to replace slag at the dosage of 0, 5, 10, and 20% by weight of the binder, while PVA fiber was added at the dosage of 0, 1, and 2% by volume of the mixture. Samples were synthesized via alkali activator with 1.0 of silicate modulus and cured at room temperature for 28 days. Compressive strength test, permeable voids volume test, water absorprtion test, and rapid chloride penetration test were conducted for measuring the charaterisitics of alkali-activaed slag. The results showed that increasing silica fume content up to 10% in alkali-activated slag improved compressive strength and chloride penetration resistance. Addition of PVA fibers up to 1% by volume enhanced strength and chloride penetration resistance, but exceeding this led to reduced strength and durability due to increased void formation in the matrix.

• Molecular & Cellular Toxicology
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• 제3권4호
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• pp.306-313
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• 2007

The welding fume has been implicated as a causal agent in respiratory disease such as pneumoconiosis. The molecular mechanism by which welding fume induces toxicity in the lung is still unknown, but studies have focused on histological structure and indirect approach measuring the pulmonary damage markers. In the present study, gene expression profiles were analyzed in the lung of rats exposed by manual metal-arc stainless-steel (MMA-SS) welding fume for 30 days using Affymetrix GeneChip$^{(R)}$. Totally, 379 genes were identified as being either up- or down-regulated over 2-fold changes (P<0.01) in the lung of low- or high-dose group and were analyzed by using hierarchical clustering. We focused on genes involved in immune/inflammation responses were differentially regulated during lung injury induced by welding fume exposure. The information of these deregulated genes may contribute in elucidation of the inflammation mechanism during lung injury such as lung fibrosis.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.107-108
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• 2010

본 연구에서는 실리캬 흄 대체재로써 SFFB를 사용한 고강도 콘크리트 인장부재의 인장강성 특성에 대한 실험결과를 제시한다. 본 연구는 60 및 80MPa의 압축강도를 갖는 고강도 콘크리트에서 고가의 실리캬 흄을 SFFB로 대체 가능성을 평가하는데 목적이 있다. 실험결과, 60 및 80MPa의 고강도 콘크리트 배합에서 실리캬 흄을 대체한 SFFB를 사용한 인장부재의 균열 및 하중거동 특성은 실리캬 흄을 사용한 인장 부재와 대등한 성능을 보였다.

• Computers and Concrete
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• 제26권5호
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• pp.385-395
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• 2020

The influence of combination of nano silica and silica fume, as partial cement replacement materials, on the properties of concrete has been studied through the measurement of compressive strength. The compressive strength of concrete in terms of mean, standard deviation and with-in-test coefficient of variation related to the variation in the nominated parameters have also been developed. The compressive strength data developed experimentally has been analyzed using normal-probability distribution and partial safety factors of composite concretes have been evaluated by using first order second moment approach with Hasofer Lind's method. The use of Nano silica and silica fume in concrete decreases the partial safety factor of concrete i.e., increase the reliability of concrete. The experimental results show that the properties of concrete having nano silica and silica fume in combination were better than that of a plain concrete. The SEM test results showing the level of Ca(OH)₂ in plain concrete and consumption level Ca(OH)₂ of concrete containing nano silica & silica fume have also been presented.

• 콘크리트학회논문집
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• 제15권3호
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• pp.497-503
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• 2003

Supplementary cementitious materials (SCM) such as fly ash, ground granulated blast furnace slag and silica fume are now being extensively used in concrete to control expansion due to alkali-silica reactivity (ASR). However, the replacement level of a single SCM needed to deleterious ASR expansion and cracking may create other problem and concerns. For example, incorporating silica fume at levels greater than 10％ by mass of cement may lead to dispersion and workability concerns, while fly ash can lead to poor strength development at early age, The combination of silica fume and fly ash in ternary cementitious system may alleviate this and other concerns, and result in a number of synergistic effects. The aim of the study was to enable evaluation of more realistic suitability of a silica fume-fly ash combination system for ASR resistance based on an in-house modification of ASTM C 1260 test method. The modification can be more closely identified with actual field conditions. In this study three different strengths of NaOH test solution(1N, 0.5N, and 0.25N) were used to measure the expansion characteristics of mortar bar made with a reactive aggregate. The other variable included longer testing period of 28 days instead of a conventional 14 days.