• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.130-131
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• 2014

In this study, Analyse about flowability for fiber-reinforud mortar has been focused. Organic and inorganic fibers with different length have been combinatiorly used. The results showed using combination length of the fibers decrease the flowability, comparing with plain, fracture styess has been increased, Results also showed when several kinds of fibers used together showed the highest fracture stress.

• 콘크리트학회논문집
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• 제19권2호
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• pp.233-239
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• 2007

본 연구의 주요 목적은 시멘트 복합 재료의 소성 수축 균열 제어에 폐 PET병으로부터 만들어진 재생 PET 섬유의 효과를 평가하는 것이다. PET은 플라스틱 재료라 알려진 재료로 음료수 병 등에 다양하게 적용되어 왔다. 그렇지만 폐 PET 병은 사용 후에 환경적 측면에서 큰 문제점으로 부각되고 있다. 따라서 폐 PET 병을 재활용하는 방법에 대한 연구는 환경 및 경제적 측면에서 중요하게 되었다. 폐 PET 병을 재활용하는 방법 중 시멘트 복합 재료의 보강 섬유로 사용하는 방법은 효과적인 방법 중에 하나이다. 본 연구에서는 시멘트 복합 재료의 소성 수축 균열에 재생 PET 섬유의 형상 및 길이의 효과를 얇은 슬래브 실험을 통해서 조사하였다. 실험 계획은 섬유의 형상, 길이 및 혼입률의 영향을 이해하기 위하여 수행하였다. 재생 PET섬유의 형상은 straight, crimped및 embossed type의 3가지 형상을 포함하며, 각 3가지 섬유형상 마다 3가지 수준의 섬유 혼입률 및 2가지 종류의 섬유 길이에 대해서 조사하였다. 실험 결과 재생 PET섬유는 시멘트 복합 재료의 소성 수축 균열에 효과적이었다. 섬유의 길이의 관점에서 길이가 긴 섬유는 섬유의 형상이 동일할 때 섬유체적비가 적을 때 효과적이며, 섬유체적비가 증가하면 길이가 짧은 섬유가 더욱더 효과적이었다. 또한 embossed type의 섬유는 적은 섬유 혼입률에서 다른 형상의 섬유보다 소성 수축 균열 제어 효과가 우수하였으며, 높은 섬유 혼입률에서는 straight type의 섬유가 다른 형상의 섬유보다 시멘트 복합 재료의 소성 수축 균열 제어에 가장 효과적이었다.

• 대한기계학회논문집
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• 제16권2호
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• pp.200-206
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• 1992

The effect of fiber diameter and gauge length on pull-out test for the interfacial properties in fiber reinforced resin composites have been investigated and these results have been arranged as statistical analysis. The fiber and matrix resins used for this study were stainless steel fiber (SUS316) and carbon fiber (high strength type), epoxy and high density polyethylene resin. From this study, it has been found that shear strength are constant regardless of gauge length of pull-out test and coefficient of variation depend on fiber diameter. In addition, it has been found that the interfacial shear strength decreased with the increasing fiber diameter, and in all case, Weibull parameter (m) has approximately 1.2/C.O.V.

• Geomechanics and Engineering
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• 제18권5호
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• pp.503-513
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• 2019

In the present, the liquefaction potential of fiber-reinforced sandy soils was investigated through the energy-based approach by conducting a series of strain-controlled cyclic simple shear tests. In the tests, the effects of the fiber properties, such as the fiber content, fiber length, relative density and effective stress, and the test parameters on sandy soil improvement were investigated. The results indicated that the fiber inclusion yields to higher cumulative liquefaction energy values compared to the unreinforced (plain) ground by increasing the number of cycles and shear strength needed for the liquefaction of the soil. This result reveals that the fiber inclusion increases the resistance of the soil to liquefaction. However, the increase in the fiber content was determined to be more effective on the test results compared to the fiber length. Furthermore, the increase in the relative density of the soil increases the efficiency of the fibers on soil strengthening.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.155-160
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• 2002

A new fabrication method of FBG sensor with gage length shorter than 10 mm is introduced using the reflection prism with special coating on the surface. It is verified that the bandwidth of FBG sensor increases exponentially as the gage length of it decreases. The transverse stress and strain gradient induced by local stress concentration which occurs during curing has an influence on the FBG sensor with gage length of 2 mm less than that of 10 mm.

• 한국세라믹학회지
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• 제32권9호
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• pp.989-994
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• 1995

Rigid porous carbon fiber composites with the uniform pore size distribution were prepared by vacuum forming from water slurries containing carbonized PAN fibers, a phenolic resin and ceramic binders. The composites were designed to use for highly efficient carbon fiber filters for particulate filtration and gas adsorption. As the as-received carbon fibers of 1mm in length were milled to an approximate average length of 300${\mu}{\textrm}{m}$, modulus of rupture (MOR) of the composite filter was increased from 1MPa to the value larger than 5 MPa. Modulus of rupture (MOR) for the composite filter fabricated using the milled carbon fiber was increased from 5 MPa to 10 MPa as the carbonization temperature of the PAN fiber was raised from 90$0^{\circ}C$ to 140$0^{\circ}C$. The air permeability and an average pore size of the composite filter were increased from 40 to 270cc/min.$\textrm{cm}^2$ and from 35 to 80${\mu}{\textrm}{m}$, respectively, as the apparent porosity increased from 80 to 95%. It was shown that the MOR of the carbon fiber composite filter was dependent primarily on the average length of carbon fiber, carbonization temperature and the type of bonding materials.

• Structural Engineering and Mechanics
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• 제87권4호
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• pp.375-389
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• 2023

In many fiber concrete beams with Carbon Fiber Reinforced Polymer (CFRP), debonding occurs between the carbon sheets and the concrete due to the low strength of the bonding resin. A total of 42 fiber concrete beams with a cross-section of 10×10 cm with a span length of 50 cm are fabricated and retrofitted with CFRP and subjected to a 4-point bending test. Graphene Oxide (GO) at 1, 2, and 3 wt% of the resin is used to improve the mechanical properties of the bonding resins, and the effect of length, width, and the number of layers of CFRP and resin material are investigated. The crack pattern, failure mode, and stress-strain curve are analyzed and compared in each case. The results showed that adding GO to polyamine resin could improve the bonding between the resin and the fiber concrete beam. Furthermore, the optimum amount of nanomaterials is equal to 2% by the weight of the resin. Using 2% nanomaterials showed that by increasing the length, width, and number of layers, the bearing and stiffness of fiber concrete beams increased significantly.

• 접착 및 계면
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• 제19권2호
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• pp.60-67
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• 2018

본 연구에서는 친환경 천연섬유인 케나프의 표면을 Chemlok 402를 함유하고 있는 접착용액으로 전처리하였을 경우, 케나프/천연고무 복합재료의 경화거동, 경도, 인장특성 그리고 마모특성에 미치는 섬유 표면처리 유 무, 섬유함량 및 섬유길이의 영향을 조사하였다. 복합재료를 구성하는 케나프섬유 함량은 평균 케나프섬유의 길이가 약 2 mm로 일정한 상태에서 각각 0, 5, 10, 15, 20 phr로 달리하였다. 또한 섬유함량이 5 phr로 고정된 상태에서 평균 섬유길이는 각각 2 mm, 35 mm, 70 mm로 달리하여 각 특성을 비교하였다. 천연고무 복합재료의 경화거동을 나타내는 Tmax 값과 tc90 값, Shore A 경도, 인장탄성률 그리고 마모저항성은 케나프섬유 함량과 길이에 크게 의존하였다. 이러한 특성들은 케나프섬유의 표면을 접착용액으로 전처리한 경우가 처리하지 않은 경우보다 더 우수한 특성을 나타냈다. 이러한 현상은 전처리된 케나프섬유와 고무매트릭스 사이의 계면접착 상태가 개선되었기 때문이다. 본 연구결과는 천연섬유강화 복합재료의 물성을 향상시키기 위해 접착용액의 적절한 사용이 가능하다는 것을 제시하여 준다.

• 펄프종이기술
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• 제35권5호
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• pp.72-79
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• 2003

Nalita wood (Trema orientalis), one of the fastest growing woods in the world, is characterized anatomical, morphological and chemical properties at annual growth ring level in order to investigate as papermaking raw material. The proportion of fibers and vessel was increased with an increase of growth ring (from pith to bark). The fiber length of Nalita was increased with increasing growth ring, and an average fiber length was about 817 um. The average basic density of Nalita was about 0.38 g/cc. The total lignin & holocellulose in Nalita were increased and ash & alcohol-benzene extract decreased from pith to bark. These values were about 23.5 - 24.4 ％, 78.1 - 80.1 ％, 1.04 - 0.92 ％ and 2.1 - 1.8 ％, respectively. The xylan was the predominant sugar in the hemicellulose of Nalita.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.128-129
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• 2014

In this study, flowability of the mortar added with length change and combination of steel and inorganic fiber has been tested to evaluate the performance of fiber-reinforced mortar. The following results could be made as the conclusion. Early age flow of the mortar has been decreased when fibers added. Slump also decreased with the adding of fibers. For the air content, comparing with Plain, all the specimens with fibers showed higher air content than Plain., Addition of every kinds fibers showed the similar EIS test results.