• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.117-122
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• 1999

The antiwashout concrete which is a type of specific concrete is manufactured by using a plenty of superplasticizer with the non-dispersible underwater concrete admixture, and the application of it on construction site is being increased. But when we measure choride ion content by using the potentiographic tester, because it is over total chloride ion content(0.3kg/㎥ under) of Korean Concrete Specification, the claim of construction site is being presented on the quality of antiwashout concrete. Accordingly, hte aim of this study is to verify actual chloride ion content of antiwashout concrete by chloride ion analysis due to chemical admixtures by performance of antiwashout concrete. In conclusion the actual chloride ion content of antiwashout concrete is overestimated by anion($OH^-, SO4^{-2}, S^{-2}, etc) of chemical admixtures, and is proved to be as low as that of ordinary concrete.

• 콘크리트학회논문집
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• 제16권6호
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• pp.777-783
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• 2004

본 연구에서는 고로슬래그미분말과 플라이애쉬의 치환율 변화에 따른 굳지 않은 수중불분리성 콘크리트와 경화한 수중불분리성 콘크리트의 특성에 관하여 연구하고자 하였다. 실험변수는 W/C비는 50%로, S/a는 40%로 고정하고, 고로슬래그는 0, 10, n, 30, 40, 50, 60%로 치환하였으며, 플라이애쉬는 0, 10, 15, 20, 25, 30, 35%로 치환하여 고로슬래그미분말과 플라이애쉬의 치환율 변화에 따른 수중불분리성 콘크리트의 특성에 관하여 연구하였다. 굳지 않은 수중불분리성 콘크리트의 pH 현탁물질량 그리고 슬럼프플로우를 측정하였으며, 경화한 수중불분리성 콘크리트의 재령 7일, 28일, 56일의 압축강도를 측정하였다. 굳지 않은 수중불분리성 콘크리트의 pH 현탁물질량, 그리고 슬럼프플로우를 측정한 결과, 모두 대한토목학회에서 제시한 기준값과 배합설계기준값을 모두 만족하는 것으로 나타났다. 재령에 따른 경화한 수중불분리성 콘크리트의 압축강도는 전체적으로 해수에서 제작?양생한 것이 해수에 포함된 염류 중에 황산마그네슘($MgSO_4$)이 콘크리트의 수화시 발생되는 수산화칼슘($Ca(OH)_2$)과 반응하여 생성된 에트링자이트(ettringite)로 인하여 콘크리트의 부피를 팽창시켜 열화를 일으켜 담수에서 제작 양생한 콘크리트의 압축강도보다 낮게 발현되는 것으로 나타났다. 종합적으로 검토해 본 결과, 수중공사의 특성상 수질오염, 다짐의 어려움이 큰 시공상의 특성 및 압축강도특성 등을 고려할때 고로슬래그미분말 및 플라이애쉬의 최적 치환율은 30%인 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.199-202
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• 1999

Recently, the antiwahout underwater concrete with an natiwashout admixture has been increasingly used for underwater structures. However, the credibility of antiwahout underwater concrete was brought up as problems because it was seldom applied to fields. In this study, experiments were made on the basic properties of antiwashout underwater concrete replaced with GGBF Slag from 40% to 60% to improve its properties. Resultant to the test, we got the results as follows; the difference of U-type heght was decreased, and the slump flow was increased. Whereas the amount of suspended solids became high as to increasing the replacement ratio of GGBF Slag, pH value became low. Beacause the ratio of compressive strengths (in water compared to in air) at 28days was obtained over 90%, its value is satisfied with 70% of a criterion.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.457-460
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• 2003

This paper discusses laboratory evaluations to assess the physical properties of antiwashout underwater concrete (AWC) containing pozzolanic materials such as fly ash (FA), blast furnace slag (SG) and metakaolin(MK). For the experiments, pH value, suspended solids, slump flow, efflux time and compressive strength were tested. According to the results from compressive strength test, MK10 showed the very high compressive strength characteristic during the entire curing days, but the rate of strength development was decreased as time goes by.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.301-307
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• 1997

This paper is evaluated for properties of aggregate and antiwashout admixture not only to minimize segregation and water contamination of underwater concrete but also to meet concrete quality required. Two antiwashout admixtures used in this study were available domestically and slump flow, pH, setting time, and filing property of fresh concrete and the compressive strength, flexural strength under water and in the air under 2 different curing conditions ($10^{\cire}C$ and $20^{\cire}C$ ) were measured. Compressive strength ratio of specimens cured in and water temperature $10^{\cire}C$ /$20^{\cire}C$ added HPEC and HPMC was 64% and 89%, respectively. Relative compressive strength of 2 kinds observed higher concrete added HPEC, 3% at $10^{\cire}C$ curing temperature, 34% at $20^{\cire}C$ . The flexural strength of specimens made under water was 1/4~1/6 of compressive strength similar to the existing data in the literature.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.195-198
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• 2000

Recently, the anriwashout underwater concrete has been increasingly used for underwater structures such as vary high diaphrame walls of high strength massive concrete structures. In this study, experiments were made on the fundamental properties of antiwashout underwater concrete replaced with Fly Ash from 10% to 30% to improve its properties. Resultant to the test, we got the results as follows; the value of slump flow wasi ncreased, the setting, time was very delayed, and the heat evolution amount decreased, whereas the amount of suspended solids became high, and pH value became low as to increasing the replacement ratio of Fly Ash. Also the ratios of compressive strength (in water compared to in air) at 28day were obtained over 90%, and these values were satisfied with 70% of a criterion.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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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.

• 한국해양공학회지
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• 제19권6호통권67호
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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.

• 콘크리트학회지
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• 제13권2호
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• pp.23-29
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• 2001

• 한국농공학회논문집
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• 제49권3호
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• pp.43-50
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• 2007

The purpose of this study was to determine the optimum mix proportion of latex modified mortar for agricultural underwater concrete structures repair. The experimental variables included a latex and antiwashout admixture amount, binder-sand ratio, water-binder ratio. This study were evaluated a repair performance and environment effect of latex modified repair mortar for agricultural underwater concrete structures. The pH test was conducted to evaluated the environmental effect and the flow test was peformed to evaluated the workability. Also, compressive, flexural and bond tests were conducted. Test results show that the optimum mix proportion of latex modified repair mortar for agricultural underwater concrete structures, was achieved by 1:1.5 binder-sand ratio, 5% latex ratio (weight of binder), 1.3% antiwashout admixture ratio (weight of binder), 0.33 water-binder ratio and 10% silica lune replacement ratio (weight of cement). The environmental effect and repair performance of optimum mix proportion satisfied all target performance.