• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.50-51
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• 2015

In marine and coastal environments, penetration of chloride ions is one of the main mechanisms causing concrete reinforcement corrosion. Currently, most of experimental investigations about submerged penetration of chloride ions are started after the four weeks standard curing of concrete. The further hydration of cement and reduction of chloride diffusivity during submerged penetration period are ignored. To overcome this weak point, this paper presents a numerical procedure to analyze simultaneously cement hydration reaction and chloride ion penetration process. First, using a cement hydration model, degree of hydration and phase volume fractions of hardening concrete are determined. Second, the dependences of chloride diffusivity and chloride binding capacity on age of concrete are clarified. Third, chloride profiles in hardening concrete are calculated. The proposed numerical procedure is verified by using chloride penetration test results of concrete with different mixing proportions.

• 한국컴퓨터산업학회논문지
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• 제9권3호
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• pp.137-142
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• 2008

염소이온 침투로 인해 철근 부식에 가장 큰 영향을 끼치는 인자는 염소이온 표면농도이다. 본 연구에서는 염소이온 표면농도에 따른 염해 진행 정도를 개발한 프로그램을 통하여 해석적으로 접근하였다. 또한 해석 프로그램을 통하여 염소이온 표면농도에 따른 내구수명을 산정하였다. 염소이온 표면농도가 600ppm인 경우도 염소이온 침투 깊이가 32.3mm 정도로 나타났다. 콘크리트의 피복두께를 40mm를 유지한다면 염소이온 표면농도가 600ppm일 때 콘크리트의 내구수명은 167년으로 검토되었다.

• Architectural research
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• 제20권1호
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• pp.27-34
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• 2018

To improve the chloride ingress resistance of concrete, slag is widely used as a mineral admixture in concrete industry. And currently, most of experimental investigations about non steady state diffusion tests of chloride penetration are started after four weeks standard curing of concrete. For slag blended concrete, during submerged chloride penetration tests periods, binder reaction proceeds continuously, and chloride diffusivity decreases. However, so far the dependence of chloride ingress on curing ages are not detailed considered. To address this disadvantage, this paper shows a numerical procedure to analyze simultaneously binder hydration reactions and chloride ion penetration process. First, using a slag blended cement hydration model, degree of reactions of binders, combined water, and capillary porosity of hardening blended concrete are determined. Second, the dependences of chloride diffusivity on capillary porosity of slag blended concrete are clarified. Third, by considering time dependent chloride diffusivity and surface chloride content, chloride penetration profiles in hardening concrete are calculated. The proposed prediction model is verified through chloride immersion penetration test results of concrete with different water to binder ratios and slag contents.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.802-805
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• 2004

This study was performed to investigate the effect of mineral admixture' type and replacement ratios on the chloride penetration resistance of concrete which was immersed in the artificial chloride solution. The chloride penetration resistance was evaluated by penetration depth and chloride diffusion coefficient. As a result, all of the mineral admixtures were effective on the chloride penetration resistance of concrete compared to ordinary portland cement only.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.401-404
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• 2008

균열은 콘크리트에 염소이온과 같은 유해한 물질의 침투경로가 되어 내구성에 심각한 열화를 야기한다. 따라서 고내구성 재료를 사용한 콘크리트 휨부재에서의 균열 발생에 따른 염소이온 침투특성을 검토하고자 하였다. 이를 위해, 고내구성 재료를 적용한 보에 하중을 가하여 휨균열을 도입시키고, 촉진 염화물 침투실험(RCPT)과 장기 염화물 침투실험을 실시하여 염화물 침투 특성을 파악하였다. 실험결과에 따르면, 고내구성 재료를 적용한 부재는 균열이 발생하여도 일반 콘크리트 부재에 비해 높은 염화물 침투 저항성을 보였다. 특히 고로슬래그 미분말을 적용한 경우, 균열 부재의 장기 염화물 침투 실험에서 탁월한 염화물 침투 저항성을 보였다.

• Computers and Concrete
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• 제6권5호
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• pp.391-401
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• 2009

This paper presents a study of the strength and chloride penetration of blended Portland cement mortar containing ground palm oil fuel ash (POA) and ground river sand (GS). Ordinary Portland cement (OPC) was partially replaced with POA and GS. Compressive strength, rapid chloride penetration test (RCPT) and chloride penetration depth of mortars were determined. The GS only asserted the packing effect and its incorporation reduced the strength and the resistance to chloride penetration of mortar. The POA asserted both packing and pozzolanic effects. The use of the blend of equal portion of POA and GS also produced high strength mortars, save cost and excellent resistance to chloride penetration owing to the synergic effect of the blend of POA and GS. For chloride depth, the mathematical model correlates well with the experimental results. The computer graphics of chloride depth of the ternary blended mortars are also constructed and can be used to aid the understanding and the proportioning of the blended system.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.225-228
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• 2004

In order to estimate the chloride ion penetration, the model, which considers diffusion and sorption, is proposed on the basis of Finite Element Method (FEM). The FEM program provides the estimation of chloride concentration according to cyclic humidity and sorption. After the humidity diffusion analysis is carried out, the chloride ion diffusion and sorption analysis are conducted on the basis of the preestimated humidity data in each element. Each element has different analysis variables at different ages and locations. At early ages and constant outer humidity, the difference between inner and outer relative humidity causes the chloride ion penetration by sorption. As the humidity diffusion reduces the difference with age, the effect of sorption on the chloride ion penetration decreases. By the way, the cyclic humidity increases the effect of sorption on the chloride ion penetration at early ages, and the quantity of chloride ion around steel at later ages. Therefore, the in-situ analysis of chloride ion penetration for marine concrete structures must be performed considering the cyclic humidity condition and the long term sorption.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.259-260
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• 2012

As RC structures in the marine environment rapidly increase, the interest and the importance of Chloride Penetration durable design have been growing. However, there is hardly any domestic Chloride Penetration durability of RC structures designed analysis programs. Currently, Chloride Penetration durable design method is studied and launched actively as a program in the United States, Europe, Japan and etc., but it is limited to Chloride Penetration durability of RC structures excluded from maintenance construction. Also, the level of dependence on the foreign technology is high; the foreign program is imported and used when needed. The main objective is to compare and to evaluate with the durability assessment program and several conditions when considering the design of Chloride Penetration durability through the programs developed abroad.

• Computers and Concrete
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• 제17권2호
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• pp.189-199
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• 2016

Chloride penetration is considered as a most crucial factor for the determination of the service life of concrete. A lot of experimental tools for the chloride penetration into concrete have been developed, however, the mechanism was based on only diffusion, although permeability is also main driving forces for the chloride penetration. Permeation reacts on submerged concrete impacting for short to long term durability while capillary suction occurs on only dried concrete for very early time. Furthermore, hydrostatic pressure increases in proportional to measured depth from the surface of water because of the increasing weight of water exerting downward force from above. It is thought, therefore, that the water pressure has a great influence on the chloride penetration and thereby on the service life of marine concrete. In this study, new experiment is designed to examine the effect of water pressure on chloride penetration in concrete quantitatively. As an experiment result, pressure leaded a quick chlorides penetration by a certain depth, while diffusion induced chlorides to penetrate inward slowly. Therefore, it was concluded that chloride should penetrates significantly by water pressure and the phenomena should be accelerated for concrete exposed to deep sea. The research is expected as a framework to define the service life of submerged concrete with water pressure and compute water permeability coefficient of cementitious materials.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.25-26
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• 2018

In this study, the device was developed for evaluating the effect of pressure on chloride ion penetration of concrete. And chloride-ion penetration depth and water soluble chloride contents was evaluated concrete using ordinary portland cement and blast-furnace slag cement using developed device. As a result, chloride ion penetration of concrete was promoted according to the action of pressure and the exposure period. and the incorporation of blast-furnace slag was effective for chloride attack resistibility under pressure.