• 콘크리트학회논문집
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• 제17권3호
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• pp.467-472
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• 2005

Asphalt emulsion is manufactured by the emulsification of asphalt, and is considered as an energy-saving, ecologically safe material because it does not need any heating processes with gas emission and fire hazard in its use. This study is concerned with evaluating the feasibility of the use of an asphalt emulsion as a poly-meric admixture. Asphalt-modified mortars using an experimentally manufactured asphalt emulsion were prepared with various polymer-cement ratios, and tested far the mechanical properties such as strengths and adhesion and the properties related to durability such as water absorption, permeation, carbonation and chloride ion penetration. As a result, the waterproofness, carbonation resistance and chloride ion penetration resistance of the asphalt-modified mortars were markedly improved with an increase in the polymer-cement ratio, but their compressive strength and adhesion to mortar substrates were reduced with increasing polymer-cement ratio. Therefore, it is recommended to control their polymer-cement ratio to be $10\%$ or lower in their practical applications. Further study to improve their compressive strength and adhesion is needed.

• 산업기술연구
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• 제37권1호
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• pp.32-36
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• 2017

In this study, as part of a research on the development of economical high-performance concrete with high strength and high quality, the physical properties of high-performance concrete were analyzed by substituting a certain amount of low-cost domestic silica fume exempted from the re-importation type distribution structure of the domestic production and the existing high-priced silica fume distribution structure. Performing tests to identify the physical properties of the fresh and hardened concrete and durability analogy of the concrete which use low-cost domestic silica fume and imported silica fume, the chloride ion penetration resistance test result showed that the strength difference between the low-cost silica fume and the imported silica fume is not big but the strength of the low-cost silica fume was measured higher than the imported silica fume. The chloride ion penetration resistance of all variables was measured as "very low". Since the low-cost domestic silica fume can be used as a high-performance admixture of concrete, the results suggest that it is possible to produce a more economical high-performance concrete.

• 대한건축학회논문집:구조계
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• 제35권5호
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• pp.153-160
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• 2019

The purpose of this study was to investigate the mechanical and durability characteristics of latex-modified concrete using ultra rapid hardening cement : four types of mechanical tests including compressive strength, modulus of elasticity, flexural strength and bond strength were performed; and seven types of durability tests including resistance of concrete to chloride ion penetration, freeze-thaw resistance, scaling resistance, coefficient of thermal expansion, cracking tendency, abrasion resistance and drying shrinkage were performed. Required material performance of each test was determined in accordance with the Korea specification for repair of concrete and pavement repairing materials. The test results satisfied the required material performances, and presented a good mechanical and durability characteristics. In particularly, the materials showed early development of compressive strength, flexural strength and bond strength at 3 and 4 hours after curing. SEM photos were also taken to investigate the micro structures of the materials after chloride ion penetration test.

• 한국산학기술학회논문지
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• 제15권2호
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• pp.1188-1194
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• 2014

본 연구의 목적은 플라이 애시, 고로슬래그 미분말, 실리카흄을 사용하여 4성분계 콘크리트의 염해 저항성능을 평가하기 위한 것이다. 본 연구에서는 압축강도, 탄성계수, 염수침지 시험, 염화물 확산계수 및 침투계수를 실시하였다. 4성분계 콘크리트의 염화물 확산계수와 침투계수는 재령 17주에 $0.032{\times}10^{-12}m^2/sec$와 650 coulomb으로 측정되었다. 또한 침지시험 결과 염화물 이온 침투깊이와 염화물량은 3.7 mm and $10.211kg/m^3$로 측정 되었다. 이러한 결과로부터 플라이 애시, 고로슬래그 미분말, 실리카흄을 사용하여 제조한 4성분계 콘크리트는 염해 저항성능과 역학적 특성이 매우 높을 것을 알 수 있었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.52-53
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• 2018

As a result of exposing the concrete at 1 and 6 atm in order to evaluate the salt resistance of the pressurized marine concrete, the pressure resulted in promoting the chloride ion penetration of the concrete. Particularly, the amount of water soluble chloride in the surface area tends to increase rapidly, and this cause is considered to be highly correlated with the size of the capillary pores of the concrete. On the other hand, the blending of blast furnace slag was effective to increse chloride attack resistibility even under the pressure.

• Advances in concrete construction
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• 제4권4호
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• pp.305-317
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• 2016

Porous materials such as concrete could be subjected to aggressive ions transport. Durability of cement paste is extremely depended on water and ions penetration into its interior sections. These ions transport could lead different damages depending on reactivity of ions, their concentrations and diffusion coefficients. In this paper, chloride diffusion process in cement hydrates is simulated at atomistic scale using molecular dynamics. Most important phase of cement hydrates is calcium silicate hydrate (C-S-H). Tobermorite, one of the most famous crystal analogues of C-S-H, is used as substrate in the simulation model. To conduct simulation, a nanopore is considered in the middle of simulation cell to place water molecules and aggressive ions. Different chloride salts are considered in models to find out which one is better for calculation of the transport properties. Diffusion coefficients of water molecules and chloride ions are calculated and validated with existing analytical and experimental works. There are relatively good agreements among simulation outputs and experimental results.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.196-200
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• 1996

In the case of construction under the marine environment the durability of concrete structures is everely deteriorated by the penetration of salts which results in the corrosion of reinforcing steel. To verify the effect of corrosion protection of reinforcing steel by isolating the penetration of chlorideion this study investigated the bond strength between painting material and concrete, the degree of the penetration-diffusion of chloride ion and the accelerated corrosion test using different potential. Results show that the painted concrete has little the penetration-diffusion of cholride and the reinforcing steel in painted concrete is little corroding.

• 한국농공학회논문집
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• 제55권6호
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• pp.11-17
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• 2013

This study was performed to evaluate the chlorine ion penetration resistance, chemical resistance and freezing and thawing resistance used ordinary portland cement, crushed coarse aggregate, crushed sand, river sand, fly ash, limestone powder, blast furance slag powder and superplasticizer to find optimum mix design of low carbon green concrete for structures. The performance of low carbon green concrete used fly ash, limestone powder and blast furnace slag powder were remarkably improved. This fact is expected to have economical effects in the manufacture of low carbon green concrete for offshore structures. Accordingly, the fly ash, limestone powder and blast furnace slag powder can be used for offshore structure materials.

• 콘크리트학회논문집
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• 제14권6호
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• pp.883-891
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• 2002

염해 환경에 노출된 철근 콘크리트 구조물의 내구수명 산정은 일반적으로 철근의 위치까지 염소이온이 확산하여 임계농도에 도달하는데 걸리는 시간으로 추정해 오고 있다. 염소이온의 확산해석 방법은 많은 연구들이 콘크리트만을 고려한 염소이온 확산해석을 수행하여 염소이온의 분포를 예측하곤 철근 깊이에서의 염소이온 농도가 임계농도에 도달하는 시간을 내구수명 예측에 사용하는 방법을 제시하고 있다. 콘크리트에서의 염소이온의 확산 해석에서 콘크리트 내의 철근을 고려하지 않은 염소이온 확산해석은 실제 철근의 염소이온 확산 계수가 거의 '0'인 점을 고려하면 실제 염소이온의 확산 거동을 제대로 반영하지 못한 것이다. 따라서, 본 연구는 철근의 영향을 고려한 염소이온 확산 해석을 통하여 철근이 염소이온 확산 거동에 미치는 영향을 규명하고 합리적인 철근 부식 시작 시간을 예측하고자 하였다. 이를 위하여 본 연구에서는, 또한 시멘트 성분과 배합 특성에 영향을 받는 염소이온의 구속효과를 고려하여 확산해석을 수행하였으며, 염소이온 확산 해석의 주요 변수는 실제 구조물에서 염소이온의 확산해석에 영향을 미칠 것으로 예상되는 철근의 직경, 철근 덮개 크기, 시멘트 종류 그리고 배합 등의 다양한 변수를 고려하였으며 철근을 고려하지 않은 경우와 비교 분석하였다.

• 콘크리트학회논문집
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• 제26권4호
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• pp.517-524
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• 2014

이 연구는 해양환경이나, 방사선 폐기물 및 가스 저장 시설과 같은 고내구성을 요하는 철근콘크리트 구조물의 내구성 향상 기법 및 장수명화 기술의 개발을 목적으로, 우수한 성능을 갖는 비스페놀 A형 및 F형 에폭시수지와 염화물 이온 흡착제인 아질산형 하이드로칼루마이트를 병용한 폴리머 시멘트 모르타르의 염화물이온 침투 저항성, 탄산화 저항성, 건조수축 및 철근부식 촉진시험을 통하여 내구성과 방청성을 비교 검토하는 것이다. 그 결과, 폴리머 결합재비에 관계없이 칼루마이트 치환에 의해 폴리머 시멘트 모르타르의 내구성이 일부 저하하는 경향을 보였으나, 이는 폴리머 결합재비의 증가와 함께 크게 개선되었다. 방청성의 경우 비스페놀 A형 및 F형 에폭시수지 사용으로 시멘트 매트릭스 내 생성된 폴리머 필름에 의한 이온 및 가스투과 저항성이 증대하였으며, 칼루마이트의 염화물이온 흡착과 아질산이온 방출에 의해 우수한 방청효과를 보였다. 이상의 연구 결과로부터 철근콘크리트의 고성능 다기능 폴리머 혼입 시멘트 모르타르 제품의 개발이 가능할 것으로 판단된다.