• 한국정밀공학회지
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• 제17권5호
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• pp.63-69
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• 2000

The main target of this research is investigating the relations between mechanical properties and injection conditions, like injection pressure, packing pressure and packing time for various contents ratio of glass fiber and resin. In general idea, high injection pressure produces high strength of molded parts as a monotonic function. but it was revealed that high pressure does not make high strength directly through various experiments of injection molding. In this experiments, PA66 was selected as resin and Glass Fiber was selected as reinforcing fiber Fiber reinforcement was controlled, as 14%, 25%, 33%, 44% of total volume and packing pressure was divided 55%, 65%, 75%, 85% of reference pressure, i.e. 100% equal to 1400kgf/$\textrm{cm}^2$. Finally, tensile testing was executed for injected test specimen. Optimum results based on authors' experiments have been obtained under conditions of 25% and 33% of glass fiber contents. Tensile strength rather depends on the packing pressure and packing time than injection pressure. Especially almost equal value of tensile strength was obtained for various percentage of packing and injection pressure as 65%, 75% and 85% of reference pressure.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.173-178
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• 2001

This study investigates the effect of fiber content on the fracture behavior of thermoplastic composites (glass fiber/polypropylene). The fiber contents used were 20%, 30%, and 40% by weight. Fracture tests were performed using compact tension (CT) specimens made of composite sheets of three fiber contents (20%, 30%, 40%). The results showed that compliance, fracture load, and fracture toughness were affected by the fiber content. The compliance decreased with fiber content while the fracture load increased as the fiber content increased. The fracture toughness also increased as fiber content increased. Specifically, the fracture toughness increased 14% as the fiber content increased from 20% to 40%.

• 한국결정성장학회지
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• 제25권6호
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• pp.263-271
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• 2015

기존의 내알칼리 유리섬유는 복합재료의 보강섬유로 가장 널리 사용되고 있는 일반적인 E-glass fiber보다 우수한 내화학 특성을 갖고 있으나 용융유리의 점도가 너무 높아 섬유화가 어려운 문제점을 가지고 있다. 본 연구에서는 지르코니아 함량이 상용 제품에 비해 낮은 범위에서 지르코니아 함량별로 내알칼리유리섬유를 제조하고 이들의 특성을 E-glass 섬유와 비교하였다. 지르코니아의 함량을 0.5~16 wt%까지 변화시키면서 제조한 각각의 배치원료를 $1600^{\circ}C$에서 2시간 용융하여 투명하고 맑은 유리를 얻을 수 있었다. 이들 유리는 약 90 %의 높은 가시광 투과율을 나타내었고, 열적특성에서 $703{\sim}887^{\circ}C$의 연화점을 나타내었으며, 지르코니아의 함량이 증가함에 따라 연화점이 상승하는 경향을 나타내었다. 지르코니아 함량이 4 wt%인 조성을 E-glass 조성과 비교한 결과, 연화점에서는 $-94^{\circ}C$의 차이를, 고온점도에 있어서는 log3 온도가 $+68^{\circ}C$, log5 온도가 $-13^{\circ}C$의 차이를 나타내었다. 내알칼리 유리섬유를 알칼리용액에 48시간 및 72시간 침적 후 SEM을 통해 섬유의 내침식성이 양호함을 확인할 수 있었고, 인장강도도 일반 E-glass 섬유에 비해 48시간에서 1.7배와 72시간에서 2.2배의 높은 값을 나타냄을 알 수 있었다. 결론적으로 이러한 내알칼리 유리섬유는 쉬운 제조조건과 낮은 지르코니아 함량에도 불구하고 좋은 특성 때문에 일반적인 내알칼리 유리섬유로서 널리 사용될 수 있을 것으로 판단되었다.

• 한국농공학회논문집
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• 제58권3호
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• pp.21-27
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• 2016

This study was performed to evaluate engineering properties of carbon and glass fiber reinforced recycled polymer concrete. Fiber reinforced recycled polymer concrete were used recycled aggregate as coarse aggregate, natural aggregate as fine aggregate, $CaCO_3$ as filler, unsaturated polyester resin as binder, and carbon and glass fiber as fibers. The compressive and flexural strength of carbon fiber reinforced recycled polymer concrete were in the range of 68~81.5 MPa and 19.1~21.5 MPa at the curing 7days. Also, the compressive and flexural strength of glass fiber reinforced recycled polymer concrete were in the range of 69.4~85.1 MPa and 19~20.1 MPa at the curing 7days. Abrasion ratio of carbon and glass fiber reinforced recycled polymer concrete were decreased 21.6 % and 11.6 % by fiber content 0.9 %, respectively. After impact resistance test, drop numbers of initial and final fracture were increased with increase of fiber contents. Accordingly, carbon fiber and glass fiber reinforced recycled polymer concrete will greatly improve the hydraulic structures, underground utilities and agricultural structures.

• 한국도로학회논문집
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• 제20권4호
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• pp.27-34
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• 2018

PURPOSES : The objective of this study is to evaluate the physical properties of recycled asphalt mixtures reinforced with glass fiber. METHODS : Firstly, mixing design was conducted on recycled asphalt mixture for use of 50% recycled aggregate. Various laboratory tests were performed on four types of recycled asphalt mixtures with different glass fiber content to evaluate the physical properties. The laboratory tests include indirect tensile strength test, dynamic modulus test, Hamburg wheel tracking test and tensile-strength ratio to evaluate cracks, rutting and moisture resistance of mixtures. RESULTS : The indirect tensile strength of fiber reinforced glass increased about 139.4%. As a result of comparing the master curves obtained by the dynamic modulus test, the elasticity was low in the low temperature region and high in the high temperature region when the glass fiber was reinforced. The glass fiber contents of PEGS 0.3%, Micro PPGF 0.1% and Macro PPGF 0.3% showed the highest moisture resistance and rutting resistance. CONCLUSIONS : The test results show that use of glass fiber reinforcement can increase the resistance to cracking, rutting, and moisture damage of asphalt mixtures. It is also necessary to validate the long-term performance of recycled asphalt mixtures with glass fiber using full scale pavement testing and field trial construction.

• 콘크리트학회논문집
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• 제13권3호
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• pp.213-220
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• 2001

콘크리트에 폐유리의 사용은 알칼리 실리카 반응(ASR)의 팽창으로 균열과 강도저하를 일으킬 수 있다. 본 연구에서는 폐유리의 혼입률과 색상(갈색, 녹색) 및 폐유리로 인해 발생되는 ASR팽창을 저감시키기 위해 섬유의 종류(강섬유, 폴리프로필렌섬유)와 섬유혼입률에 따른 ASR팽창과 강도특성을 분석하였다. 연구결과 녹색의 폐유리가 팽창량이 비교적 작기 때문에 갈색의 폐유리보다 더욱 유용하며, ASTNM C 1260의 시험에 있어서 폐유리의 혼입으로 인한 퍼시멈(pessimum)량은 발견되지 않았다. 또한, 폐유리와 함께 섬유의 혼입은 폐유리의 실리카와 시멘트 페이스트의 알칼리 사이의 ASR로 인한 팽창과 강도 저하를 저감시키는데 효과적인 것으로 나타났다. 특히 폐유리 혼입률 20%에 대해서 강섬유를 1.5vol.% 혼입하였을 경우 팽창은 40%까지 감소하였으며 휨강도는 폐유리만을 혼입한 것(8$0^{\circ}C$ $H_2O$ 양생)에 비해 110%의 강도발현을 나타내었다.

• 한국환경보건학회지
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• 제22권2호
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• pp.43-57
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• 1996

To characterize worker's exposure to glass fibers, to find the correlation between airborne total dust concentrations and fiber concentrations and to recommend an appropriate evaluation method for worker's exposure to fibrous dusts in glass wool industry, we carried out this study. Average respirable fiber levels at five factories were 0.013-0.056 f/cc, and fairly below the OSHA PEL, 1 f/cc. A factory showed the lowest airborne fiber level, 0.013 f/cc, which was different significantly from those of other factories of which average fiber concentration was 0.046 f/cc. The cutting and grinding operations of insulation products resulted in higher airborne fiber cocentrations than any other processes(p<0.05). To characterize airborne fiber dimension, fiber length and diamter were determined using phase contrast microscope. The geometric means of airborne fiber lengths were $42-105 \mu m$. One factory had airborne fibers whose length distribution(GM = $105 \mu m$) was different from those of other factories(GM = $42-50 \mu m$). The percentages of respirable fibers less thinner than 3 gm were 38.9-90.9% at four factories, and two factories of them had the higher percentages than others. The findings explain for variation of airborne fiber diameters between factories. On the other hand, between the processes were the difference of fiber-length distributions observed. The cutting and grinding operations showed shorter fiber-length distributions than the fiber forming one. However, fiber-diameter distributions or respirable fiber contents were similar in all processes. The airborne fiber concentrations and the dust concentrations had relatively weak correlation(r=0.25), thus number of fibers couldn't be expected reliably from dust amount. Fiber count is appropriate for assessing accurate exposures and health effects caused by fibrous dusts including glass fibers. Ministry of Labor have established occupational exposure limit to glass fibers as nuisiance dust, but should establish it on the basis of respirable fiber concentration to provide adequate protection for worker's health

• Korean Chemical Engineering Research
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• 제50권1호
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• pp.30-34
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• 2012

선박용 부품에 적용할 수 있는 고분자 소재를 개발하기 위한 연구의 일환으로, 폴리에스테르 수지의 인장강도에 미치는 실리카와 절단 유리섬유의 영향을 조사하였다. 실리카와 절단 유리섬유의 첨가량 및 표면 개질에 사용된 커플링제의 농도를 변화시키면서 실험을 수행하였다. 표면 개질을 수행하지 않은 경우, 유리섬유의 첨가량이 증가하면 인장강도가 증가하였으나, 실리카는 첨가량이 증가할수록 인장강도가 감소하였다. 커플링제를 사용하여 첨가제의 표면을 개질하면 인장강도에 긍정적인 효과를 나타내었으며, 개질된 실리카와 절단 유리섬유를 혼합 첨가하면 인장강도의 증가에 상승효과를 나타내는 것을 알 수 있었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.147-151
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• 2001

This study was performed to evaluate the internal and external factors affecting external strength of the 3-layer polymer composite pipes made of polymer mortar and fiber-glass reinforced plastic. Twenty four sandwich type 3-layer polymer composite pipes were made of polymer mortar and fiber-glass reinforced plastic by centrifugal method. The objective of this study was to evaluate the effects the of polymer mortar thickness for and core fiber-glass contents per unit area on external strength of 3-layer polymer composite pipes. For the more economical and practical design of 3-layer polymer composite pipe, further study should be done for the various polymer mortar, fiber-glass and different ratio of the inside/outside FRP thickness.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.822-827
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• 2003

This study was performed to evaluate the internal and external factors affecting external strength of the 3-layer polymer composite pipes made of polymer mortar and fiber-glass reinforced plastic. Twenty four sandwich type 3-layer polymer composite pipes were made of polymer mortar and fiber-glass reinforced plastic by centrifugal method. The objective of this study was to evaluate the effects the of polymer mortar thickness for and core fiber-glass contents per unit area on external strength of 3-layer polymer composite pipes. For the more economical and practical design of 3-layer polymer composite pipe, further study should be done for the various polymer mortar, fiber-glass and different ratio of the inside/outside FRP thickness.