• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.83-86
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• 1998

Recently, underwater concrete constructions are increasing. Therefore it is considered important to control the quality of underwater concrete. In this paper, we have an intention of evaluating fundamental properties of underwater concrete using the Ground Granulated Blast Furnace Slag (GGBF Slag). Thus, it has been investigated that the slump flow of the concrete, pH value and suspended solids in solution, compressive strength on both of specimens made above and below water. Also the percentage of GGBF Slag was found to alter the filling-up in underwater concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.451-454
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• 2000

Recently, the antiwashout underwater concrete has been increasingly used for underwater structure such as high strength massive concrete structures. However, Concrete has poor quality ad durability due to dilution with separating cementitious material. In this study, specimens were made with antiwashout underwater concrete replaced with mineral admixtures to improve their properties and were placed in air, water, and salt water. To estimation the chloride ion permeation in concrete, ASTM C 1202 Test was performed. The experimental results demonstrate that the increase of the admixtures improved the properties of antiwashout underwater concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.41-46
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• 2000

In recently, though the development of antiwashout admixture, if's possible to construct in underwater with the concrete which is improved segregation resistance of material, filling and self-leveling. It is generally to use this method with Europe and Japan as the central figure, and also the construction case is reported in korea. There's some advantages to add the fly ash in plain concrete. The objective of this study is to find the characteristics of fresh underwater antiwashout concrete which is followed by the blend rate of fly ash.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.57-61
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• 2000

This experimental study was carried out to estmate the effects of mixing dosage rate and blain on the compressive strength properties of antiwashout underwater concrete admixed with finely ground granulated blast furnace slag. The experimental parameters are slag contents(0, 20, 30, 40, 50, 60%). As a result the compressive strength have a high correlation with slag blended ratio. Thus, it is possible to calculate the modulus of modified age using compressive strength of antiwashout underwater concrete blended with slag.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.366-372
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• 1996

This paper persents the characteristics and properties of the five domestic and foreign-made anti-washout admixtures commercially available in Korea. These admixtures have been analysed by experiments to compare among others specifically on the following items : air content, slump-flow, hardening time, pH, filling condition, turbidity, content of chloride, compressive strength of underwater concrete and ratio of ambient / underwater concrete compressive strength. The mix design for comparison has been set according to the Japanese practicesince there is still no guideline concerning underwater concrete available domestically.

• Journal of Ocean Engineering and Technology
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• v.25 no.3
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• pp.40-46
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• 2011

This paper describes the effects of fly ash replacement on the sulfate resistance of antiwashout underwater concrete which was replaced cement by fly ash from 0% to 50%. and the experimental works were performed on sulfate acceleration test of 5%$Na_2SO_4$ solution to find out the variance of length and weight of specimens. The experimental result shows that the length of specimens of antiwashout underwater concrete age at 180day was highly increased compare with normal concrete by acceleration test. but the mixture which was replaced 50% of fly ash shows reduction of the expansion, weight various, compare with normal concrete specimen. accordingly by using fly ash as admixture in antiwashout underwater concrete in sea environment, it will makes more durable for the attacks of sulfate by sea water.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.40-45
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• 2008

This paper describes the effects of fly ash replacement on the water tightness of antiwashout underwater concrete, which replaced the cement with fly ash from 0% to 30%. The experimental work was performed to find out the depth of permeation of concrete specimens cast in air and cured in 23 $^{\circ}C$ tap water using an open center pressure type of water permeation tester. The results showed that the permeation depth values of antiwashout underwater concrete were deeper than normal concrete, but that an admixture using fly ash during antiwashout underwater concrete casting in air made it more watertight than normal concrete according to the water permeation testing. SEM observations of the specimens of fly ash antiwashout underwater concrete showed that it wasmore packed with structures because of the pozzolan reaction of the fly ash and cement.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.29-34
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• 2005

This paper describes the effect of fly ash replacement on seawater resistance of anti-washout underwater concrete, which was replaced cement by fly ash from $0\%$ to $50\%$. The experimental work was performed to find out the variations of length and weight of specimens, using a chloride acceleration test in $40\^{\circ}$C The results shaw that the admixture using fly ash on an anti-washcout underwater concrete in the sea environment makes it more durable for the attacks of chloride by seawater. Also, the length of specimens of anti-washout underwater concrete, at age 180 days, increased substantially, compared with normal concrete; however, the mixture in which cement was replaced $50\%$ of fly ash shows $93\%$ reduction of the expansion, compared with the normal anti "washout underwater concrete specimen.

• Journal of Ocean Engineering and Technology
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• v.14 no.4
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• pp.30-34
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• 2000

The concretes cast in the sea water would be likely to be rich mix and mass concrete. Therefore it is important to check out the hydration heat of concrete and to reduce it to prevent the concrete from processing the temperature crack. Recently the antiwashout agent is used on underwater concrete for preventing from the segregation of concrete in the water. The experimental studies were done for the combined cement replaced by fly ash 30%unit weight of binder to study on the characteristics of hydration heat of antiwashout underwater concrete, and its characteristic was discussed by comparing on cast in sea water with anther one in air. The present paper showed that the hydration heat concrete replaced by 30%of fly ash was more significantly reduced than the normal concrete. The hydration heat of antiwashout underwater concrete was highter than that of normal concrete, but it was reduced lower than the normal concrete by adding fly ash.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.324-329
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• 1998

Recently the use of the underwater concrete with the antiwashout admixture is increased considerably. When we intend to apply it to the field, we must consider the water temperature effect. In this study, we investigate the properties of setting time, early strength, hydration temperature history and core strength with the antiwashout underwater concrete in the water temperature 8$^{\circ}C$, 14$^{\circ}C$ and 22$^{\circ}C$ respectively. As a result of experiment, as the water temperature is decreasing, setting time is delayed twice of three times and early strength is lower from 10% to 50%. Therefore to compensate the decrease of the early strength, we used the accelerator and investigated the concrete properties.