• 콘크리트학회논문집
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• 제17권4호
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• pp.663-670
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• 2005

The present study concerns the influence of binder type on the chloride-induced corrosion being accompanied by the chloride threshold level (CTL), chloride transport and as their results the corrosion-free lift. Two levels of cement content, $30\%$ PFA and $65\%$ GGBS concrete were employed. It was found that the most dominant factor to the CTL is the entrapped air void content at the steel-concrete interface, irrespective of the chloride binding capacity, binder type and acid neutralisation capacity of cement matrix. The CTL for lower interfacial air void contents was significantly increased up to $1.52\%$ by weight of cement, whereas a same mix produced $0.35\%$ for a higher level of voids. Because of a remarkable reduction in the diffusion fur GGBS concrete, its time to corrosion ranges from 255 to 1,250 days, while the corrosion-free life for control varies from 20 to 199 days sand for $30\%$ PFA concrete from 200 to 331 days.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.598-602
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• 2003

The general red-mud minerals consist of hematite, sodalite, anatase, quartz, gibbsite and miner impurities. This gives serious environmental damage for the ocean disposal. It mixed with chloride compound and the content of chlorine is about 2,000-3,000ppm. This paper can be suggested the chloride reduction technology that is applied basically mineral processing by physical separation. Then it can be possible to produce the totally 24wt. $\%$ useful red-mud which chloride content is less then 400ppm.

• 한국식품위생안전성학회지
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• 제4권1호
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• pp.37-44
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• 1989

멸치를 물로 씻은 후 식염 10%, 15%, 20% 및 식염과 염화칼리 1:1 홈합염 10%를 각기 첨가하여 1~12주간 숙성할 때 불휘발성 아민의 함량과 미생물의 변화와 시중에 유통중인 멸치젓의 불휘발성아민 함량을 조사하였다. 불휘발성아민은 식염농도가 높을수록 생성량이 적었고 숙성기간별 생성량은 histamine의 경우 숙성 초기부터 증가하여 6주째에 식염 10%, 멸치젓이 657.8ppm으로 최고치를 나타낸 후 감소하기 시작하여 숙성 12주째는 식염 20%, 멸치젓이 210.8ppm으로 가장 적었고 혼합염 10% 멸치젓이 310.8ppm으로 가장 많이 생성되었다. Cadaverine과 putrescine은 숙성 8주째까지 생성량이 증가한 후 점차적으로 줄어들었고 tyramine은 숙성 10주째까지 RPthrwmd가한 뒤 숙성 12주째 현저히 감소하였다. 시중 유통품과 식염 함량이 비슷한 20% 멸치젓의 12주째 실험결과를 비교하면 시중 유통품의 불휘발성 아민 함량이 전반적으로 높게 나타났다. 미생물의 변화는 숙성 초기에는 Achromobacter 속, Aeromonas 속 및 Pseudomonas속이, 숙성 중기에는 Pediococcus속 , Microc....us 속 및 Lactobacillus 속이 많았으며 숙성 후기에는 Sacchromyces 속이 증가하였고 전 숙성기간 동안 미생물은 109주가 분리되었다.

• 한국자원식물학회지
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• 제12권2호
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• pp.166-169
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• 1999

본 실험은 볍씨에 염화망간의 농도를 2500, 3500 및 4,500ppm을 처리하여 벼의 초기생육에 대한 생육반응, 엽록소 함량, 유리 proline 및 SOD활성변화를 자포니카형인 일품벼를 실험재료로하여 실험한 결과를 요약하면 다음과 같다. 1. 근장은 무처리보다 망간농도 4,500ppm에서는 0.3cm로 망간농도가 증가할수록 뿌리 생장이 억제되었다. 2. 발아율은 망간농도 3,500ppm에서 68%였으나 망간농도 4,500ppm에서 는 43%로 가장 낮았다. 3, 엽록소 함량은 무처리보다 고농도인 4,500ppm 에서 1.16mg으로 가장 낮았다. 4. 유리 proline 함량은 무처리에서는 발아 후 3일과 8일에서 큰 차이를 보이지 않았고 발아 후 3일째 망간농도2,500ppm과 4,500ppm에서 각각 3,286$\mu$mole과 5,872$\mu$mole로 망간농도가 높아질수록 유리 proline 함량이 증가하였다. 5. SOD 활성은 발아 후 2일째 무처리가 762EU인 것에 비해 망간농도 4,500ppm에서는 1,693EU로 가장 높았다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.665-670
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• 2001

The studies on chloride diffusion of concrete have been done so far by many researchers. However, there are few studies that present the effects of other attacks on chloride diffusion properties. Therefore, in this study the experiments are carried out to show the effects of combined attacks, such as carbonation, sulfate attacks, on chloride diffusivity in concrete. The specimens are made by varying cement type and replacement ratio of fly ash. The results show that cement type and replacement of fly ash do not affect greatly chloride diffusion properties. And concrete treated by combined attacks show a little higher chloride content than those treated by chloride solution only. Therefore, the effects of these factors should be taken into account in predicting the penetration of chloride ion in concrete.

• 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.

• 한국안전학회지
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• 제19권3호
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• pp.89-94
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• 2004

Most reinforcements in concrete are constructed by steel. Corrosion of reinforcement is the main cause of damage and early failure of reinforced concrete structures. The corrosion is mainly professed by the chloride ingress. In general, chloride in concrete can be discriminated by two components, total chloride and fire chloride. This paper provides a testing method on the coefficient of chloride diffusion in concrete and the relationship between total chloride and free chloride in concrete for the composition of predicting model on diffusion rate of chloride. In order to complete this predicting model, this study will use chloride penetration characteristic, diffusion coefficient and experiment of color change on silver nitrate solution. This predicting model is going to help that grasp special quality on salt content inclusion of concrete structure that is exposed in chloride environment. Accurate predicting model can be effectively used not only in selecting of repair time but also in preventing from various deteriorations.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.699-704
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• 2003

Corrosion of reforcement is the main cause of damage and early failure of reinforced concrete structures. The corrosion is mainly progressed by the chloride ingress. In this paper, an experimental study is executed to investigate the effect of concrete properties and testing method on the coefficient of chloride diffusion. Also, it is compared that the relationship between total chloride and free chloride in concrete. According to this experiment results, w/c ratio and testing method effect on chloride diffusion coefficient of concrete. As w/c ratio is increased, diffusion coefficient in concrete is also increased. Diffusion coefficient obtained by each testing method show the different value, respectively. Also, the content of free chloride in 7days curing concrete is increased as w/c ratio is increased.

• Computers and Concrete
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• 제13권1호
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• pp.71-82
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• 2014

Chloride ion ingress is one of the major problems that affect the durability of concrete structures such as bridge decks, concrete pavements, and other structures exposed to harsh saline environments. Therefore, durability based design of concrete structures in severe condition has gained great significance in recent decades and various mathematical models for estimating the service life of rein-forced concrete have been proposed. In spite of comprehensive researches on the corrosion of rein-forced concrete, there are still various controversial concepts in quantitation of durability parameters such as chloride diffusion coefficient and surface chloride content. Effect of environment conditions on the durability of concrete structures is one of the most important issues. Hence, regional investigations are necessary for durability based design and evaluation of the models. Persian Gulf is one of the most aggressive regions of the world because of elevated temperature and humidity as well as high content of chloride ions in seawater. The aim of this study is evaluation of some parameters of durability of RC structures in marine environment from viewpoint of corrosion initiation. For this purpose, some experiments were carried out on the real RC structures and in laboratory. The result showed that various uncertainties in parameters of durability were existed.

• International Journal of Concrete Structures and Materials
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• 제10권1호
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• pp.61-73
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• 2016

In predicating the probability distribution of chloride diffusion coefficient of recycled aggregate concrete ($D_{RAC}$), the morphological characteristics of three phases, i.e., the old attached mortar, the natural aggregate and the new mortar, should all be taken into account. The present paper attempts to develop a probability density evolution method (PDEM) to achieve this. After verifying the derived PDEM results with experimental results, the effects of old attached mortar to the $D_{RAC}$ are examined in a quantitative manner. It is found that (1) the variation of the attached mortar content is much sensitive to $D_{RAC}$; (2) given the probability distribution of the content and chloride diffusion coefficient of old mortar, the probability distribution of DRAC can be analysed based on the PDEM; and (3) the critical chloride diffusion coefficient at a certain assurance rate can be obtained by the PDEM. The analysis results of this investigation will be valuable to the durability design for RAC.