• 콘크리트학회지
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• 제13권2호
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• pp.23-29
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• 2001

• 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 2001년도 가을 학술발표회 논문집
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• pp.427-432
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• 2001

In this study, crushed sand is blended with river sand and sea sand, to investigate the quality change of antiwashout underwater concrete with variation of blend ratio of crushed sand(0%, 20%, 40%, 60%, 80%, 100%). To see experiment conclusion, the more blend ratio of crushed sand increases, the more unit weight increases. Because the for that specific gravity of crushed sand is higher comparatively than that of river sand and sea sand. Higher compressive strength is measured following the order of river sand, crushed sand, sea sand regardless of age and casting-curing condition. Except for case of using river sand, blend ratio of 40% is appeared on most compressive strength. So the optimum blend ratio of crushed sand is 40% from the view point of compressive strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.271-275
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• 1998

Recently, in the trend of using aggregate, it is common that coarse aggregate is replaced with crushed stone and fine aggregate is replaced with sea sand as a replacing aggregate. In this study, to judge the adaptability of using antiwashout underwater concrete, we used mixed sand (river sand : sea sand= 5 : 5) and changed W/C. After carrying out the research on the strength development of the compressive strength of specimen, tensile strength, fluxural strength which is produced and cured in the air and salt water, we founded that when W/C was low and the amount of AWA and SP were increased, the state of strength development was excellent.

• 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 2003년도 봄 학술발표회 논문집
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• pp.1077-1080
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• 2003

High reactivity metakaolin (HRM) is a manufactured pozzolan produced by thermal processing of purified kaolinitic clay. Field performance and laboratory research of concrete containing HRM have demonstrated its value for bridge decks, bridge deck overlays, high-strength concrete and masonry products. This paper discusses laboratory evaluations to assess the physical properties of antiwashout underwater concrete (AWC) containing HRM, such as pH value, suspended solids, slump flow, and compressive strength. There were not much variations of pH value with the changing HRM contents, but suspended solid test showed that the amount of suspended solids of AWC with 10 and 20% of HRM were reduced in comparison with plain. Due to the fast hydration and reaction property of HRM, slump flow was decreased with increasing HRM contents. According to the results of compressive strength test, AWC with 10 and 20% of HRM showed higher strength characteristic than plain at all curing ages.

• 콘크리트학회논문집
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• 제13권4호
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• pp.336-345
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• 2001

수중콘크리트는 재료분리에 의한 품질의 저하, 현장 주변의 오염 등 문제점이 있을 뿐만 아니라 고강도 및 초대형 수중콘크리트 구조물을 축조해야 할 필요성이 요구되면서 새로운 재료 및 공법의 개발이 요망된다. 그래서 수중불분리성 콘크리트의 재료분리와 수화열의 저감 및 장기강도 증진을 목표로 제조한 수중불분리성 콘크리트의 현장적용성에 대한 연구를 착안하게 되었다. 모형 실험체(I)에 의한 실험결과, 슬럼프 플로우 58cm인 수중불분리성 콘크리트를 24㎥/hr 정도의 속도로 타설할 경우, 5m의 단부까지 약 1분 정도 소요되었으며, 타설면은 거의 수평을 유지하는 시공성을 나타내었으며, 각 부위별 코어 공시체의 압축강도는 240 kgf/$\textrm{cm}^2$을 상회하는 값임을 알 수 있었다. 한편, 모형 실험체(II)에 사용된 고강도용 수중불분리성 콘크리트의 pH값과 현탁물질량은 각각 경과시간 30분에서 10.0~11.0 및 51 mg/$\ell$, 초결 및 종결시간은 각각 30 및 37시간 정도 그리고 슬럼프플로우 값은 53$\pm$2cm범위였다. 이 콘크리트로서 27㎥/hr 정도의 속도로 타설한 결과, 철근 배근의 유무에 관계없이 유동속도는 큰 차이가 없었으며 유동 구배는 거의 수평면을 유지하였다. 코어 공시체의 압축강도 및 탄성계수는 유동거리가 멀어질수록 약간 감소하였으나 중앙부위에서 가장 큰 값을 나타내었다.

• 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.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.338-350
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• 2010

As existing materials for ground reinforcement, chemical grout material using cementitous materials and waterglass was used. But many problems in terms of ground reinforcement effects were implicated. In this study, for development and applicability verification of new materials, viscosity, fluidity, permeability, Self-Leveling, keeping of drilled hole, antiwashout underwater, resistance of water (groundwater dilution and minimize material eluting) and the early strength and long-term strength characteristics of developed materials was confirmed, and material standards, and establishing construction standards for the various model tests were conducted. As a result, high viscosity, flowability, permeability and keeping of drilled hole characteristics are excellent, in addition to the early strength properties, dilution does nat occur to groundwater, including groundwater is available for dealing with environmental issues. Application of basic and reinforcement method by Filler function in addition to structure can also or development of a new concept can be expected. In addition, middle and large-diameter drilled shaft, micropile, ground anchors, soil-nailing, steel pipes multi-grouting reinforcement for cement injection process could be used enough to even be considered.

• 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.