• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.161-166
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• 1998

The main object of this study is to examine the basic properties of fresh concrete as well as hardened concrete using several types of cement such as ordinary portland cement, sulphate resisting portland cement, blast furnace slag cement, ternary blended cement. In addition, effects of each cement on the durability including drying shrinkage, freeze-thawing resistance, resistance of chloride ion penetration, carbonation of concrete were investigated. As the results of this study, it was proved that most of the properties of concrete using each cement were similar, but there were some differences in bleeding, setting time, resistance of chloride ion penetration and carbonation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.133-134
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• 2014

As a previous research, improved durability of concrete by filling capillary pores with waste cooking oil was suggested as a method of controlling carbonation of the concrete replaced high volume of SCMs. on the other hand, the emulsified refined waste cooking oil for better mixing performance had a drawback of reducing air content related with decreasing freeze-thawing resistance. As a solution of this problem, surface applying method was suggested instead of adding in mixing process, and in this research, the performance regarding concrete durability are evaluated comparing emulsified refined cooking oil with water-repelling agent.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.116-117
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• 2019

In this research, Proctor insertion resistance test values and Durometer A type hardness values were compared and analyzed between the setting times of the concrete using CGS for Fine Aggregate, and the results are summarized as follows. 1) The Proctor penetration resistance test value and the hardness value of Durometer A type showed a high correlation in the form of a curve. 2) About surface finish The resolution exceeding the hardness value of the Durometer A type uses about 25 HD, and in the case of termination, about 35 HD, and is considered to be effective for determining the surface finishing work time. The possibility to do is expected.

• 한국산학기술학회논문지
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• 제16권7호
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• pp.4960-4968
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• 2015

본 논문에서는 숏크리트 구조물의 염해 내구성을 개선하고자 광물성 혼화재의 종류 및 혼입량에 따라 유럽의 시험규준인 NT BUILD 492에 준하여 염해 저항성을 평가하였다. 또한 정적강도 및 염소이온 침투저항성 등의 역학적 특성을 함께 평가하였다. 부순 골재를 사용하여 굵은 골재 최대치수 10mm의 숏크리트용 혼합쇄석 골재를 제작하였다. 재령 28일 압축강도를 기준으로 실리카퓸 15% 혼입 변수가 67.55MPa로 가장 높은 강도를 나타냈으며, 플라이애시와 고로슬래그는 혼입률이 증가할수록 강도가 감소하는 것으로 나타났다. 염소이온 침투저항성 시험에서는 기본 배합에서 "높음" 등급으로 나타났으며, 혼화재료의 경우 플라이애시를 제외하고 모든 변수에서 침투저항성이 매우 증가하는 경향을 보였다. 촉진 염화물 확산 침투시험으로 KCL, ACI, FIB 기준에 대한 내구수명을 평가하였다. 시험결과 실리카퓸 15%를 혼입한 변수에서 가장 낮은 확산계수를 얻었다, KCI 기준으로 약 65년의 내구수명을 갖는 것으로 나타났으며, FIB 기준으로 131년의 내구수명을 갖는 것으로 나타났다. KCI, ACI, FIB 기준 중 모든 변수에서 KCI 기준의 내구수명이 가장 낮은 것으로 평가되었다.

• 한국구조물진단유지관리공학회 논문집
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• 제24권2호
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• pp.50-59
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• 2020

고 흡수성 폴리머(SAP)는 콘크리트 내부에서 물을 흡수하여 팽창하며 물을 방출하면서 수축한다. 이 과정을 통해 콘크리트는 내부 양생 효과를 얻을 수 있지만 팽창한 SAP가 차지하고 있던 공간은 공극으로 존재하게 된다. 따라서 본 연구에서는 SAP를 혼입한 콘크리트의 기초 물성 및 염화물 침투 저항성을 평가하여 SAP의 내부 양생과 공극에 의한 영향을 평가하였다. 또한 SAP에 의한 내부 양생 효과를 평가하기 위해 양생 조건을 수중 양생과 봉함 양생으로 구분하여 실시하였다. 실험 결과, 수중 양생의 압축강도는 혼입율에 따라 큰 차이가 없었으며, 봉함 양생의 경우에는 SAP의 혼입율이 증가함에 따라 압축 강도가 증가하는 경향을 나타냈다. 봉함 양생의 경우 내부 양생 효과가 압축 강도 증가에 영향을 준 것으로 판단된다. 염화물 확산계수 측정 결과, SAP의 혼입율 증가에 따라 확산계수가 감소하는 경향을 나타냈으며, 특히 봉함 양생은 내부 양생 효과로 인해 수화 반응이 촉진되어 염화물 침투 저항성이 더욱 개선된 것으로 판단된다. 양생 조건이 다른 경우 표면 전기저항을 이용해 염화물 침투 저항성을 평가하는 것은 부적절한 것으로 판단된다.

• The Plant Pathology Journal
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• 제23권3호
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• pp.203-209
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• 2007

Infection structures were observed using a fluorescence microscope at the penetration sites on the leaves of potato plants pre-inoculated with the bacterial strains Pseudomonas putida TRL2-3, Micrococcus luteus TRK2-2, and Flexibacteraceae bacterium MRL412, which mediated an induced systemic resistance on potato plants against late blight disease caused by Phytophthora infestans. In order to compare the infection structures on the leaves expressing systemic acquired resistance, the leaves of potato plants pre-treated with DL-3-amino butyric acid (BABA) were also observed after challenge inoculation with the same pathogen. The infection structures were investigated. The total number of germination and appressorium formation of P. infestans were counted. Furthermore, the frequencies of fluorescent epidermal cells at the penetration sites, which indicate a defense response of plant cell, were estimated. There were no differences on the germination rates of the fungal cysts among the untreated control, BABA pre-treated, and bacterial strains pre-inoculated plants. However, appressorium formation was slightly decreased on the leaves of BABA pre-treated plants compared to those of untreated as well as bacterial strains pre-inoculated plants. Furthermore, the frequencies of fluorescent cells of BABA pre-treated and bacterial strains pre-inoculated were higher than that of untreated plants, indicating an active defense reaction of the host cells against the fungal attack. On the other hand, the pre-treatment with BABA caused a stronger fluorescent of epidermal cells at the penetration sites compared to the pre-inoculation with the bacterial strains. Interestingly, the frequency of fluorescent cells by BABA, however, was lower than that by the bacterial strains. Based on the results it is suggested that the infection structures showing resistance reaction on the leaves of potato plants were different between by pre-inoculation with bacterial strains and by pre-treatment with BABA against the late blight pathogen.

• Corrosion Science and Technology
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• 제19권2호
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• pp.100-107
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• 2020

The demand for powder-coated steel used in the marine industry is increasing owing to their superior corrosion resistance. However, the powder coatings used in commercial products can deteriorate easily by the penetration of brine. In an attempt to suppress brine penetration into the powder coating and significantly increase the corrosion resistance, three types of oxide particles were added to the coating. Electrochemical impedance spectroscopy tests in 3.5% NaCl solution were performed to evaluate the corrosion behaviors of the powder coating with oxide particles. The results showed that the addition of SiO₂ particles to a powder coating severely decreased the corrosion resistance due to the easy detachment of agglomerated SiO₂ particles with a coarse size from the coating layer. In contrast, the TiO₂ and SnO₂-added coatings showed better corrosion resistance, and the TiO₂-added coating performed best in the test conducted at room temperature. However, conflicting results were obtained from tests conducted at a higher temperature, which may be attributed to the effective suppression of brine penetration by the fine SnO₂ particles uniformly distributed in the coating.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.241-244
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• 2004

The evaluation of Single or multi-degregation of concrete coated by high performance surface penetration agency was examined through various tests, i.e., carbonation, absorption, carbonation + chloride ion and carbonation + chemical solution according to various high performance surface penetration agencies and various compressive strengths of base concrete. The 2 types of high performance surface penetration agencies were used i.e., inorganic and alcohol soluble. And 2 types of compressive strength of base concrete were used such as 21 30. MPa. The characteristics of concrete coated high performance surface penetration agency was more improved than that of non-coated concrete, and especially, water soluble inorganic agency was most effective. And if compressive strength of base concrete was low, the improved effects would be larger.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.257-260
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• 2004

The durability and water - resisting capability of nuclear concrete structures can be greatly improved as the density of concrete surface increases. Applying the surface penetration sealer to the concrete surface can increase the surface density. Therefore, the objective of this study is to identify the most suitable surface penetration sealer based on lab test. The considered parameters rate and water resistance and absorbance rate of the concrete specimen after the penetration sealer are applied. The experimental study resulted in the identification of the two most suitable surface penetration sealer based on their performance.

• Computers and Concrete
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• 제7권2호
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• pp.87-102
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• 2010

This paper discusses new capabilities developed for the Virtual Penetration Laboratory (VPL) software package to address the challenges of determining Penetration Resistance (PR) equations for concrete materials. Specifically, the paper introduces a three-invariant concrete constitutive model recently developed by the authors. The Advanced Fundamental Concrete (AFC) model was developed to provide a fast-running predictive model to simulate the behavior of concrete and other high-strength geologic materials. The Continuous Evolutionary Algorithms (CEA) automatic fitting algorithms used to fit the new model are discussed, and then examples are presented to demonstrate the effectiveness of the new AFC model. Finally, the AFC model in conjunction with the VPL software package is used to develop a PR equation for a concrete material.