• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.49-52
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• 2006

Epoxy resin has less reaction shrinkage, has better water proofing and thermal resistance than other repairing materials, to it has been applied broadly to repair and finish buildings and infrastructures. Although the ambient temperature constructed is varied with the seasons and epoxy resin has to mix with appropriate hardener due to the non self-hardening, as the real construction of it, the ambient temperature is ignored and the blending ration of epoxy resin and hardener is fixed. Also, because of the hardening time is aimed to temperature condition and the tolerance of blending ratio, we investigated the variation of viscosity according to ambient temperatures and hardener ratios. As a results of study, we can select the economical blending ratio of the epoxy resin and hardener according to site situation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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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.

• 공업화학
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• 제16권2호
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• pp.267-274
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• 2005

기존 콘크리트 압축강도의 80% 이상의 압축강도를 갖는 수중 콘크리트의 제작 및 시공을 위하여 셀룰로즈계 수중 재료분리 방지제의 제조 조건을 조사하고 이 재료 분리 방지제의 첨가에 따른 수중콘크리트의 경화 특성을 조사하였다. 제안된 수중재료분리 방지제는 시멘트량을 기준으로 methyl cellulose 0.4 wt%, silcon계 소포제 20 wt%, 응결제로서 sodium aluminate 0.1 wt%로 구성되었다. 수중 재료분리 방지제의 첨가량에 따라 현탁물질량은 감소하고, 공기량은 증가하나 시간 경과에 따른 유동성 손질은 크게 변하지 않아 작업성이 좋은 것으로 나타났다. 최적의 수중 재료분리 방지제 첨가량은 시멘트량의 0.8 wt%가 적절한 것으로 나타났으며, 이 조건에서 수중 제작한 공시체의 압축강도는 $325kg/cm^3$으로 공기중 제작한 공시체에 대한 수중공시체의 압축강도 비는 0.94로 얻어졌다.

• 콘크리트학회논문집
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• 제11권4호
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• pp.21-29
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• 1999

In this study, an experiment was performed to analyze the influence of water-cement ratio on the fundamental characteristics of antiwashout underwater concrete using blended sand (sea sand:river sand = 1:1). The water-cement ratio (45%, 50%, 55%, 60%), andtiwashout underwater agent contents (0.82%, 1.00%, 1.14% of water contents per unit volume of concrete), and superplasticizer contents (1.5%, 2.0%, 2.5% of cement contents per unit volume of concrete) were chosen as the experimental parameters. The experimental results show that the underwater segregation resistance, unit weight of hardening concrete and compressive strength were increased as the water-cement ratio decreased and as the antiwashout underwater agent contents increased. On the other hand, the flowability(slump flow) was increased to the 55% of the increase of water-cement ratio, however, it was decreased at the ratio of 60%. From this study, the antiwashout underwater concrete can potentially be used as a materials underwater work of ocean if the water-cement ratio and chemical admixture contents for the suitable balance between cost and performance are properly selected.

• 한국해양공학회지
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• 제25권2호
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• pp.85-91
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• 2011

Many protection methods such as surface coating, electric protection, or other methods have been applied to the numerous steel structures widely used in continental and marine areas to control their corrosion, which is done from an economic point of view. Most of these steel structures are primarily protected by coating methods. However, some steel piles under seawater are protected by the electric protection method, that is, either using an impressed current or a sacrificial anode method. Furthermore, environmental contamination may cause a severely corrosive environment, which, in turn, causes the accelerated corrosion of steel structures. Subsequently, coated steel structures could deteriorate more rapidly than the designed lifetime because of the acid rain caused by air pollution, etc. Therefore, a coating of marine paint exposed to seawater, that is, underwater hardening painting, is increasingly required to be fast drying as well as highly corrosion resistant. In this study, five types of underwater hardening paints were prepared with different resin series and additives. Their corrosion and water resistances were investigated using electrochemical methods such as corrosion potential, polarization curves, impedance and cyclic voltammogram measurements, etc. Even though it is generally accepted that the corrosion resistance of bare steel tends to increase with a shift of the corrosion potential in the noble direction, the corrosion resistance of a sample with a coating exhibited a relatively better tendency when it had a lower corrosion potential in this study. The corrosion current density was also decreased with a decrease in the diffusion limiting current density, which may mean that there is some relationship between corrosion and water resistance. The S sample of the ceramic resin series showed the relatively best corrosion and water resistance among those of samples, while the worst corrosion and water resistance were observed for the R sample of the epoxy resin series. The corrosion and water resistance of those samples tended to deteriorate with an increase in the immersion days, and their corrosion and water resistances were considered to be apparently improved by the types of resin and additives.

• Ocean Systems Engineering
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• 제1권2호
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• pp.111-119
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• 2011

Mines, torpedoes and improvised explosive devices (IED) pose a serious threat to the survivability of naval combatants. Inasmuch, a major goal in the design of modern combatant ships has been to eliminate or at least reduce the devastating damage caused by underwater explosion events. Even though there has been extensive research performed on the various underwater explosion phenomena and their associated effects, effective shock testing and shock proofing strategies for naval ship systems have proven to be illusive. Through the use of modeling and simulation (M&S), live fire test and evaluation (LFT&E) and laboratory testing, general guidelines for the shock hardening of shipboard equipment and systems have been developed. In this paper, current aspect of ship survivability has been addressed and future direction is discussed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.401-404
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• 2005

Because the underwater structures are subjected to the deterioration according to use environment, it is necessary to repair and reinforce when the durable performance are considered in structures. Epoxy mortar in the underwater used to the repair and reinforcement for durability. Epoxy mortar in the underwater-harding maked epoxy and filler. Filler is divided aggregate and powder system. Because aggregate take a matter too seriously to supply that alternation material is used to rapidly chilled steel slag. As result of study, it is possible that rapidly chilled steel slag can be applied for replacement materials about aggregate in epoxy mortar because the strength is not different.

• 한국산업융합학회 논문집
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• 제16권1호
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• pp.14-20
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• 2013

In this study, characteristic of new materials for repairing/reinforcement of sea and underwater structures using urethane were studied experimentally. As a results, following their good result was obtained. Materials and construction methods due to a chemical reaction, so no seams, shape or form, regardless of the variety of civil engineering in the field can be applied. Fast workability, hardening existing concrete compared with 80% in shortening. Than the existing large concrete pouring construction cost could be reduced by more than 30%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.405-408
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• 2005

The repair and reinforcement materials of the concrete structure in underwater is use to epoxy mortar for underwater-harding. Because it ensures the separation of material and a fluidity in construction, it is important to epoxy mortar This study dealt with the influence of the using of rapidly-chilled steel slag on flow, nozzle passing time, viscosity, and strength of mortar by experimental design. As results of study, this paper proved that the more the using rate of rapidly chilled steel slag increased, the more this affected the enhancement of flow, the decrease of O-lot, and the development of compressive strength, flexural strength. Also, considering the fluidity, nozzle passing time and strength of mortar, it is desirable to use RCSS300 of rapidly chilled slag.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.409-412
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• 2005

Because the underwater structures are subjected to the deterioration according to use environment, it is necessary to repair and reinforce when the durable performances are considered in structures. In generally, epoxy mortar is used to repair materials of underwater concrete. It is divided epoxy and filler which is organized cement and sand. Cement can be replaced by stone powder sludge in waste because the grading of stone powder sludge in drying state has similar to that of cement. As result of study, it is possible that stone powder sludge can be applied for replacement materials of cement in epoxy mortar, because the strength is not different when filler in epoxy mortar is alternated stone powder sludge.