• 한국세라믹학회지
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• 제50권6호
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• pp.528-532
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• 2013

Well-dispersed slurries of submicron-sized alumina powders were pressure-infiltrated in 3D preforms of mullite fibers and the effects of the particle size and infiltration pressure on the particle packing characteristics were investigated. Infiltration without pressure showed that the packing density increased as the particle size decreased due to the reduction of the friction between the particles and the fibers. The infiltrated preforms contained large pores in the large voids between the fiber tows and small pores in the narrow voids between the individual fibers. Pressure infiltration resulted in a packing density of 77% regardless of the particle size or the infiltration pressure(210 ~ 620 kPa). Pressure infiltration shortened the infiltration time and eliminated the large pores in preforms infiltrated with the slurries of smaller particles. The slurry pressure-infiltration process is thus an efficient method for the packing of matrix materials in various preforms.

• 한국건축시공학회지
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• 제17권2호
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• pp.167-174
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• 2017

고비율의 고로슬래그를 사용한 슬러리 충전 고성능 섬유보강 시멘트 복합체(SI-HPFRCC)의 역학적 성능을 평가하였다. SI-HPFRCC 실험체 제작을 위해 hooked-end 형의 강섬유를 6.4% 사용하였다. 재령에 따른 압축강도 및 압축인성과 휨강도 및 휨인성 실험을 통해 SI-HPFRCC의 역학적 성능을 평가하였다. 또한 섬유보강 효과를 평가하기 위해 SI-HPFRCC 실험체 제작에 사용된 슬러리 매트릭스의 압축강도 및 휨강도를 측정하였다. 실험결과 SI-HPFRCC의 휨거동이 재령에 따라 취성이 증가함을 확인하였다. 압축거동의 경우에도 재령에 따른 취성 증가를 볼 수 있었으나 그 정도는 미미하였다. 강도측면에서 볼 때 SI-HPFRCC는 슬러리 매트릭스에 비해 약 140~190%의 압축강도 증가와 440~500%의 휨강도 증가를 보였다.

• 한국구조물진단유지관리공학회 논문집
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• 제4권3호
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• pp.129-136
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• 2000

In the side of military purpose, the explosion proof concrete, which contributes to protect the military facilities from damages due to the explosion of bomb and to maintain their shapes, is required to develop, Therefore. in this paper, mechanical and explosion-proof properties of concrete are tested under various steel fiber contents and member size. According to the experimental results, compressive, tensile and flexural strength gain higher levels with an increase in fiber contents. It shows that energy bearing capacities are higher with an increase in fiber contents. Especially. it is confirmed that slurry infiltrated fiber concrete(SIFCON) gains high strength and has high energy bearing capacities. SIFCON is expected to be applied in the construction of explosion proof structures.

• 콘크리트학회논문집
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• 제18권5호
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• pp.703-708
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• 2006

역학적 특성이 개선되고 고성능 건설 재료로 가장 주목받고 있는 슬러리 충전 섬유 콘크리트(SIFCON)의 역학적 특성을 분석하기 위해서 양단 훅크형의 강섬유를 $4{\sim}10%$의 체적비로 혼입하여 시험체를 제작한 후, 압축강도시험과 직접인장시험을 실시하였다. 물-시멘트 비는 0.4, 슬러리의 워커빌리티를 향상시키기 위해 실리카 흄과 유동화제를 각각 시멘트 중량의 10%, 0.5%를 혼입하였다. SIFCON의 강섬유 혼입률별 시험에서 나타난 압축강도는 강섬유가 혼입되지 않은 시멘트 페이스트와 비교 하였을 때 약 $1.59{\sim}2.68$배 증가하였으며, 인장강도는 약 $2.51{\sim}8.77$ 증가하였다. 또한 강섬유의 혼입률이 증가함에 따라 인성과 연성도 크게 향상되는 것을 확인할 수 있었다.

• Computers and Concrete
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• 제26권3호
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• pp.275-283
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• 2020

Reinforced concrete (RC) does not provide sufficient resistance against impacts and blast loads, and the brittle structure of RC fails to protect against fractures due to the lack of shock absorption. Investigations on improving its resistance against explosion and impact have been actively conducted on high-performance fiber-reinforced cementitious composites (HPFRCCs), such as fiber-reinforced concrete and ultra-high-performance concrete. For these HPFRCCs, however, tensile strength and toughness are still significantly lower compared to compressive strength due to their limited fiber volume fraction. Therefore, in this study, the tensile behavior of slurry-infiltrated fiber-reinforced cementitious composites (SIFRCCs), which can accommodate a large number of steel fibers, was analyzed under static and dynamic loading to improve the shortcomings of RC and to enhance its explosion and impact resistance. The fiber volume fractions of SIFRCCs were set to 4%, 5%, and 6%, and three strain rate levels (maximum strain rate: 250 s^-1) were applied. As a result, the tensile strength exceeded 15 MPa under static load, and the dynamic tensile strength reached a maximum of 40 MPa. In addition, tensile characteristics, such as tensile strength, deformation capacity, and energy absorption capacity, were improved as the fiber volume fraction and strain rate increased.

• 한국세라믹학회지
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• 제45권4호
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• pp.204-207
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• 2008

This paper presents a new process for producing SiC fiber-SiC matrix(SiC/SiC) composites by reaction sintering. The processing strategy for the fabrication of the SiC/SiC composites involves the following: (1) infiltration of the SiC fiber fabric using a slurry consisting of Si and C precursors, (2) stacking the slurry-infiltrated SiC fiber fabric at room temperature, (3) cross-linking the stacked composites, (4) pyrolysis of the stacked composites, and (5) hot-pressing of the pyrolyzed composites. It was possible to obtain dense SiC/SiC composites with relative densities of >96% and a typical flexural strength of ${\sim}400$ MPa.

• 한국정밀공학회지
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• 제15권8호
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• pp.39-45
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• 1998

In the previous study. the powder casting was attempted as the rapid tooling. The powder casting was the process to cast dry powder into the casting mold transferred from R/P model and infiltrate the liquid binder to solidify the powder. And then, the melted copper was infiltrated to control the shrinkage rate of the final mold Conseqently, the shrinkage rate was under 0.1% through that process. The mechanical characteristic was also excellent. Generally, in the slurry casting, the alumina powder and the water soluble phenol were mainly used. However, the mechanical property of the phenol was not good enough to apply to molds directly. In this study, aluminium powder filled with epoxy is applicated to the slurry casting to solve these problems. The mechanical and thermal properties are better than phenol because the epoxy is the thermosetting resin. We achieved a successful result that the shrinkage rate is shortened about 0.047%. Futhermore, the manufacturing time and cost savings are significant. Finally, we assume that the developing possibility of this process is very optimistic.

• 한국구조물진단유지관리공학회 논문집
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• 제19권4호
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• pp.109-115
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• 2015

본 연구는 SIFCON 형태의 고성능 강섬유보강 시멘트 복합체의 섬유혼입률에 따른 휨실험을 수행하였고, 실험결과를 바탕으로 휨성능을 평가하였다. 슬러리를 충전하는 형태로 일반 섬유보강시멘트와 달리 높은 섬유혼입률을 확보할 수 있는 장점을 가지고 있다. 주요 실험 변수는 섬유혼입률 8.0%, 7.5%, 7.0%, 6.5% 및 6.0% 이며, 각 변수에 대한 휨강도 및 휨인성 특성을 분석하였다. 그 결과, 높은 섬유혼입률로 인하여 초기균열 발생 이후에도 계속적으로 하중이 증가하였으며, 최대강도 이후 충분한 잔류강도를 확보하였다. 또한 최대 50MPa 수준의 높은 휨강도를 발현하였으며, 섬유혼입률에 따른 휨강도 및 휨인성은 비례하여 증가하는 경향으로 나타났다.

• Advances in concrete construction
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• 제13권 2호
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• pp.123-132
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• 2022

This paper aims to adapt Multilinear regression (MLR) to predict the strength and toughness of SIFCON containing various pozzolanic materials. Slurry Infiltrated Fibrous Concrete (SIFCON) is one of the most common terms used in concrete manufacturing, known for its benefits such as high ductility, toughness and high ultimate strength. Assessment of compressive strength (CS.), flexural strength (F.S.), splitting tensile strength (STS), dynamic elasticity modulus (DME) and impact energy (I.E.) using the experimental approach is too costly. It is time-consuming, and a slight error can lead to a repeat of the test and, to solve this, alternative methods are used to predict the strength and toughness properties of SIFCON. In the present study, the experimentally investigated SIFCON data about various mix proportions are used to predict the strength and toughness properties using regression analysis-multilinear regression (MLR) models. The input parameters used in regression models are cement, fibre, fly ash, Metakaolin, fine aggregate, blast furnace slag, bottom ash, water-cement ratio, and the strength and toughness properties of SIFCON at 28 days is the output parameter. The models are developed and validated using data obtained from the experimental investigation. The investigations were done on 36 SIFCON mixes, and specimens were cast and tested after 28 days of curing. The MLR model yields correlation between predicted and actual values of the compressive strength (C.S.), flexural strength, splitting tensile strength, dynamic modulus of elasticity and impact energy. R-squared values for the relationship between observed and predicted compressive strength are 0.9548, flexural strength 0.9058, split tensile strength 0.9047, dynamic modulus of elasticity 0.8611 for impact energy 0.8366. This examination shows that the MLR model can predict the strength and toughness properties of SIFCON.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.303-306
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• 1999

For the purpose of Military means, explosion proof concrete, which protect the structures from the damage due to the explosion of bomb and maintain its shape, is required to develop. Therefore, in this paper, mechanical and explosionproof properties of concrete are tested under various steel fiber contents and member size. According to the experimental results, compressive, tensile and flexural strength go up with the increase of fiber contents. Energy bearing capacities is higher with the increase of fiber contents. Especially, it is confirmed that slurry infiltrated fiber concrete (SIFCON) gains in high strength and has high energy bearing capacities. SIFCON is expected to apply in the construction of explosion proof structures.