• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.2
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• pp.135-142
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• 2024

The purpose of this study is to experimentally investigate the effect of water-binder ratio and fiber type on the compressive strength and tensile performance of fiber reinforced highly ductile composites. To achieve this, four different mixtures were prepared by varying the water-binder ratio and fiber type, and compression and tension tests were conducted. The test results showed that the influence of fiber type on compressive strength was minimal, however, the WB50 series mixture exhibited a 29 % lower strength compared to the WB40 series mixture, indicating a significant effect of the water-binder ratio. On the other hand, the effect of fiber type on tensile properties was found to be more significant than that of the water-binder ratio. Tensile strain capacity ranged from 2.9 % to 6.2 %, with PE series mixtures showing 1.63 to 2.14 times higher performance compared to PVA series mixtures. Additionally, the crack patterns of the PE series mixtures were superior than those of the PVA series mixtures.

• Land and Housing Review
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• v.12 no.4
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• pp.127-137
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• 2021

Grouting has been widely used to enhance the strength of the ground and prevent waterflow into the underground space in the geotechnical engineering field. Cement with bentonite can be considered a helpful grouting material because the bentonite has a swelling ability with water. Therefore, it is essential to evaluate the characteristics of grouting materials according to the mixing ratio for a successful grouting process. In this regard, the study investigated the viscosity and bleeding characteristics of grouting materials according to the mixing ratio (i.e., water/cement ratio and bentonite/cement ratio). In the experimental result, the viscosity increases with decreasing water/cement ratio and rising proportion of bentonite by weight of cement. However, the results of the bleeding ratio show the tendency is inversely proportional to the viscosity results. Bentonite was explored in terms of the viscosity and bleeding criterion. This result is expected to be meaningful to determine the optimized mixing ratio of bentonite-cement in the grouting field.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2001.11a
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• pp.175-178
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• 2001

탄소는 활성탄으로 제조되어 다른 재료와 접촉시에 수분을 많이 흡수하여 콘크리트와 배합시 과정이 활성적으로 진행되는 점을 이용하여 조직이 좀더 밀도 있게 콘크리트 자체의 일부 단점을 보완하여 강도개선 특히 인장강도 개선을 밝히고자 하는데 본 연구의 목적이 있다. 시행착오 방법을 사용하여 콘크리트에 배합을 해나가는 과정으로 배합비를 처음 소량에서부터 점점 증가시켜나가는 방법을 택하였다. 배합에서 비 숙련에 의한 오차를 줄이기 위해서 K 건설레미콘에서 20년 경력자에 의해서 배합관리 되었고 $17^{\circ}$ $\pm$$3^{\circ}C$ 자동온도 조절기에 의해서 양생되었다.(중략)

• 베이커리
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• no.10 s.375
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• pp.110-111
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• 1999

잡지나 서적을 참고하여 제품만들기를 시도했던 사람이라면 누구나 한 번쯤 배합표에 적혀있는 재료나 구입처를 잘 몰라서 포기했던 경우가 종종 있다. 본지는 '재료색인' 지면을 마련하여 그 달에 소개되었단 재료 중 생소하거나 특이한 재료들에 대한 간단한 설명과 구입처 안내를 통해 독자들의 편의를 돕고있다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.405-406
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• 2010

This paper is a study about application of recently proposed Performance Based Mixture Design (PBMD) for design of high strength concrete (HSC) to obtain HSC mix proportion that satisfies required performances. Based on extensive experimental results obtained for various material and performance parameters of HSC, the application feasibility of the developed PBMD procedure for HSC has been verified. Also, the proposed PBMD procedure has been used to perform application examples to obtain desired target performances of HSC with optimum concrete mixture proportions using locally available materials, local environmental conditions, and available concrete production technologies.

• 레미콘
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• no.3 s.7
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• pp.33-44
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• 1986

본고는 일본「Concrete공학 」(Vol.20,No.10. Oct 1982)에 발표된 아부도산, 후등화이, 최도홍의 "전산기에 의한 레미콘의 품질관리를 위한 배합계산법"를 토대로 하여, 건설재료연구회의 "레미콘의 제조와 품질관리"를 참고로 한 것이다.

• Elastomers and Composites
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• v.38 no.1
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• pp.72-80
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• 2003

Phosphoric ester compound was employed as thermal resistant and flame retardant for chlorinated polyethylene(CPE) rubber material which is used to prepare automotive oil cooler hose. Cure characteristics, physical properties, thermal resistance, and flame retardation of CPE rubber compounds were investigated. CPE rubber which has excellent properties such as cold resistance and chemical corrosion resistance, and is inexpensive in price than existing ethyleneacrylate rubber(EAR) was used to prepare a rubber compound useful for hose. A non-halogen flame retarding agent N,N'-bis- (diphenylphosphoro) diaminohexane(BDPDH), which is condensed phosphoric ester, was synthesized and it was mixed to CPE rubber material with the range of $0{\sim}30 phr$. From the test results, rheological properties, heat resistance, and flame retardance of CPE rubber compounds were found out to be much increased. The optimum content of BDPDH to rubber which gives maximum effect on thermal resistance and flame retardation, within the range of tolerable specification for rubber materials, was determined to be 20 phr.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.465-472
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• 2012

This research aims to find an effective mixing method for controlled low strength material (CLSM) using diverse recycled industrial byproducts. This study is a fundamental research to develop and commercialize a resource-recycling CLMS that can greatly contribute to cost reduction and environmental stress relief. In the past, few studies have been performed on CLSM in Korea. This research is expected to provide fundamental data not only for development and commercialization of the resource-recycling CLSM satisfying required material performances but also serve as a ground breaking study on utilization of recycled material in construction industry and ultimately leading to advanced resource-recycling practices at national level. From the comprehensive analysis of minimum unit quantity for maximum strength and material segregation prevention, it was found that the optimal mixing condition for mixing FSD, RSID and SD material to filler-aggregate ratio (f/a) was approximately 50.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.561-572
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• 2010

This paper is a study about application of recently proposed Performance Based Mixture Design (PBMD) for design of high strength concrete (HSC) to obtain HSC mix proportion that satisfies required performances. The PBMD method which uses Satisfaction curve based on a Bayesian method is a performance oriented concrete mix proportion design procedure easily applicable to any condition and environment for a possible replacement to the current prescriptive design standards. Based on extensive experimental results obtained for various materials and performance parameters of HSC, the application feasibility of the developed PBMD procedure for HSC has been verified. Also, the proposed PBMD procedure has been used to perform application examples to obtain desired target performances of HSC with optimum concrete mixture proportions using locally available materials, local environmental conditions, and available concrete production technologies. The validity and precision of HSC mix proportion design obtained using the PBMD method is verified with the experimental and ACI presented results to check the feasibility for actual design usage.

• Composites Research
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• v.27 no.4
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• pp.168-173
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• 2014

The optimum condition of glass fiber/epoxy composites was investigated according to mixing ratio of two epoxy matrices. Novolac type epoxy and isocyanate modified epoxy were used as composites matrix. Based on chemical composition of mixing matrix, optimum mixing ratio of epoxy resins was obtained through various experiments. In order to investigate thermal stability and interface of epoxy resin, glass transition temperature was observed by DSC instrument, and static contact angle was measured by reflecting microscope. Change of IR peak and $T_g$ was conformed according to different epoxy mixing ratio. After fabrication of glass fiber/epoxy composites, tensile, compression, and flexural properties were tested by UTM by room and high temperature. The composites exhibited best mechanical properties when epoxy mixing ratio was 1:1.