• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
• /
• pp.433-436
• /
• 1999

Long-term durability of the reinforced concrete structures exposed to marine environment deteriorates seriously by the attack of the chloride ion from see water results in corrosion of steel reinforcement in concrete. Their coating effect is aluminum oxide-isocyanate-based coating material, resistance of chloride penetration, carbonation and freezing and thawing resistance were compared to acryl-based coating material and sealer type o waterproofing material. Aluminum oxide-isocyante-based and acryl-based coating material show higher resistance to chloride penetration and carbonation than the sealer type do waterproofing material and aluminum oxide-isocyanate-based coating resist about 99% of chloride penetration. Resultants to the accelerated test for freezing and thawing, coating concrete show higher resistance than non-coating concrete, respectively.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
• /
• pp.297-298
• /
• 2009

해양환경하에 건설되는 콘크리트 구조물의 염해방지를 위하여 보통포틀랜드시멘트, 고로슬래그시멘트 및 3성분계 혼합시멘트에 염해방지제를 타 입별로 치환 적용하여 모르타르 압축강도 및 염화물 확산계수를 검토한 결과, 염해방지제를 치환한 모든 배합에서 압축강도는 다소 증가하고 염화물 확산계수는 감소하는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
• /
• pp.74-77
• /
• 2003

This paper investigated the apparent chloride diffusivity of various concretes. Ten mixtures of concrete were initially prepared and tested to estimate diffusion property. The penetration depth and concentration of chloride ion were examined at the same water-binder ration. The binders were composed of normal portland cement, fly ash, ground granulated blast-furnace slag, and silica fume. From the results, it was concluded that using the mineral admixtures had a filling effect on the pore structure of cements matrix due to those pozzoanic reaction with the hydrates of cement, which increases the tortuosity of pore and makes large pore finer. And diffusivity of chloride is following: NPC100 > F10N90 > F30N70 > F20N80 > F20S05 > G30N70 > F10S05 > G30S05 > G30F15 > G50N50.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
• /
• pp.357-358
• /
• 2010

본 연구는 인공해수촉진열화시험에 의한 해양콘크리트의 내염특성 규명을 위한 연구의 일환으로서 시멘트 종류 및 도막처리에 따른 콘크리트의 특성을 분석하였으며, 시험 결과 강도 및 염소이온침투 특성 등을 고려할 경우 해양용 혼합시멘트가 콘크리트의 내염성능 개선에 효과적인 것으로 나타났다.

• Journal of Plant Biology
• /
• 제13권1호
• /
• pp.25-32
• /
• 1970

Ecological study on the reclaimed high saline soil was carried out throughout a year(1969) to elucidate the changes of the structure of halophytes communiteis and the possibilities of desalination from high saline soil by absorption of chloride ion. Results from this studies are summarized as followings; 1) The growth rates of halophytes showed a variation; maximum growth rate of Salicornia appeared on August, Chenopodium on July, Suaeda on July, Aster on August and Scirpus on June. 2) Changes of frequency of each halophyte were varied in accordance with species. Chenopodium and Salicornia have the highest frequency of all on May. However, frequency as well as density of halophytes decreased after on May due to competition for absorbing moisture in plant communities. 3) The terrestrial plants which were succeed into the reclaimed tidal land had herborized 25 species on the both side of irrigation route. 4) Each of the maximum chloride uptake by halophytes appeared on May(Salicornia and Aster), on June(Chenopodium and Scirpus), and on August(Suaeda), respectirecely 5) Among the halophytes, Salicornia was confirmed to absorb the highest amount of chloride. A possible amount of chloride uptake by all halophytes per 100 square cm reached about 24,629. ppm.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
• /
• pp.263-268
• /
• 1997

One of the principal causes of the deterioation of coastal concrete structures is the corrosion of reinforcing steel induced by the attack of chloride ions. An experimental study was performed to investigate the distribution of concentration of chloride ions in a coastal concrete structure and to measure the half-cell potential of embedded steel by using the copper-copper sulfate reference electrode. Quantitative analysis showed that the concentration of chloride ion in the aqueous phase near the surface of embedded steel exceeded a threshold value for corrosion, 0.05% by weight in concrete. The absolute value of half-cell potential at some members of embedded steel was measured to be higher than 350mV, indicating that the probability of corrosion is more than 90%. The prediction on corrosion based on the experimental measurements was confirmed by the observation of corrosion on the surface of steel bars in the concrete core taken out of the concrete structure.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
• /
• pp.149-154
• /
• 1997

In order to predict the onset of the corrosion of steel bars in the concrete, a mathematical model including the diffusion of chloride ion in aqueous phase of pores, the adsorption and desorption of chloride ions to and from the surface of solid phase of concrete, and the chemical reaction of chloride ions with solid phase was established. Finite element method was employed to carry out numerical analysis. The chlorides penetrating through the wall of concrete structure from the external environment and the chlorides contained in the concrete admixture were confirmed to be two important factors to determine the onset of corrosion of steel bars.

• Corrosion Science and Technology
• /
• 제18권2호
• /
• pp.49-54
• /
• 2019

The purpose of this paper is to present failure analysis, of the heat exchanger tube in a district heating system. SS304 stainless steel is used, as material for the heat exchanger tube. The heat exchanger operates in a soft water environment containing a small amount of chloride ions, and regularly repeats operation and standstill period. This causes concentration of chloride ions on the outer surface of the tube, as well as repeat of thermal expansion, and shrinkage of the tube. As a result of microscopic examination, cracks showed transgranular as well as branched propagation, and many pits were present, at the initiation point of each crack. Energy disperstive spectroscopy analysis showed Fe and O peak, as well as Cl peak, meaning that cracks were affected by Cl ion. Failure of the tube was caused by chloride-induced stress corrosion cracking by thermal stress, high temperature, and localized enrichment of chloride ions.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 봄 학술논문 발표대회
• /
• pp.112-113
• /
• 2021

Phosphate based inhibitor is playing a decisive role in inhibiting the corrosion of steel rebar in chloride condition. We have used different amount of ammonium phosphate monobasic (APMB) as corrosion inhibitor in mortar with different amount of chloride ions. The compressive strength, flexural strength, open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization resistance (PPR), scanning electron microscopy (SEM) and Raman spectroscopy were performed to access the effect of inhibitor on corrosion resistance. As the amount of inhibitor is increased, the compressive strength increased. The electrochemical results show that as the amount of inhibitor and chloride ions are increased, the total impedance and corrosion resistance of steel rebar increased attributed to the formation of the stable oxide films onto the steel rebar surface. It is suggested that APMB can work in high concentration of chloride ions present in concrete where phosphate ion helps in formation of stable and protective phosphate based oxide film.

• Bulletin of the Korean Chemical Society
• /
• 제32권spc8호
• /
• pp.2891-2892
• /
• 2011