• Journal of the Korea Concrete Institute
• /
• v.17 no.4 s.88
• /
• pp.663-670
• /
• 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
• /
• 2003.11a
• /
• pp.598-602
• /
• 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.

• Journal of Food Hygiene and Safety
• /
• v.4 no.1
• /
• pp.37-44
• /
• 1989

The present work was to study the changes of nonvolatile amines and microorganism in fermentation of anchovy during 12 weeks with addition of various concentration of sodium chloride. Changes of histamine occured significantly during fermentation of anchovy with 10, IS, 20% salt and 10% mixed salts (5.0% NaCl+5.0% KCl). A maximum histamine content was observed in anchovy fermented for 6 weeks while the change of histamine content was not with addition of 20% sodium chloride. Tyramine was found at highest contents in the fermented anchovy of 10% mixed salts and increased markedly in all anchovy fermented for 8 weeks. Cadaverine content was higher in fermented for all fermentation periods than in raw. During fermentation cadaverine contents increased significantly in fermented with 10% mixed salts. In contrast with that, fermented anchovy with 20% sodium chloride had very low those content and high sodium chloride concentration had influenced on amine formation. Although the highest content of putrescine was observed in fermented for 8 weeks, those content was not changed significantly during fermantation. The growth of Microflora, Achromobacter, Aeromonas and Pseudomonas were found in the in itial fermantation and Micrococus, Pediococcus, Lactobacillus and Saccharomyces were found during all fermentation periods.

• Korean Journal of Plant Resources
• /
• v.12 no.2
• /
• pp.166-169
• /
• 1999

The experiment was conducted to find the changes of early growth and chemical components such as chlorophyll content, superoxide dismutase(SOD) activity, free proline content on the different manganese chloride concentration(2,500, 3,500 and 4,500ppm) in rice seedling. Root growth was decreased in highest concentration, 4,500 ppm of Mn compared with the control and germination rate was also decreased 43% at 4,500 ppm of Mn. Chlorophyll content was decreased at Mn 4,500ppm with 1.16mg. Free proline content at 3 day after germination in Mn 4,500ppm was highest relative to the other manganese chloride concentrations. SOD activity was gradually increased as manganese chloride concentration was increased. As a result, it was suggested that an increment of free proline and SOD activity results from the higher manganese chloride concentration.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.665-670
• /
• 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
• /
• v.20 no.1
• /
• pp.27-34
• /
• 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.

• Journal of the Korean Society of Safety
• /
• v.19 no.3 s.67
• /
• pp.89-94
• /
• 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.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.05a
• /
• pp.699-704
• /
• 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
• /
• v.13 no.1
• /
• pp.71-82
• /
• 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
• /
• v.10 no.1
• /
• pp.61-73
• /
• 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.