• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.4
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• pp.35-41
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• 2007

The most agricultural concrete structures for the irrigation and drainage are exposed to the underwater condition at the irrigation period and they take the influence on very severe cold in the winter. Therefore, it is impossible to use repair materials used to the general concrete structures. The research need the development of the repair material for a performance enhance of the agricultural underwater concrete structures. This research evaluated the mechanical and durability performance of the latex modified repair mortar for underwater concrete structures which peformed the repair in the underwater according to the characteristic of the agricultural concrete structure. The latex modified repair mortar is a material that minimize the effect of the ecosystem, environment and the segregation. In this research, the construction condition of the latex modified repair mortar for agricultural concrete structures was considered and the test specimens made in the underwater condition. Test results was then compared with target performance and commercial repair mortar. Experimental test results indicated that the mechanical and durability performance of latex modified repair mortar for agricultural underwater concrete structure satisfied all target performance. Also, the latex modified repair mortar resulted in better repair performance than the commercial repair mortar.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.343-346
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• 2003

Confirmation of a damage degree and repair about a damage part are very hard for an underwater structure. And quality control of a construction is very complicated even if repair work is carried out on a damaged structure because repair work is carried out in water. If repair work is carried out while a defect part of the structure which there is in water keeps dry state, a efficient of repair is maximized. However, as for the repair technology about an underwater structure, a systematic researcher is not enough because of the environmental trouble. And, as for the effect about repair method to be applied to a currently underwater structure, it is not certainly proved. In this study The repair work of an underwater structure damaged applied the method that used a fiber panel form work. And a efficient of structure repaired was evaluated.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.3
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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.

• Corrosion Science and Technology
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• v.8 no.2
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• pp.68-73
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• 2009

An evaluation of underwater - repair coating materials was based on the premise that defective areas of the existent epoxy coating such as blistering and cracking will be repaired on spot under submerged condition. Tests include the clarification as to whether they are compatible between as-built coating and new repair coating on each concrete specimen. Candidate coating materials for repair were tested in a laboratory to scrutinize their suitability to perform the needed function satisfactorily. The qualification tests performed are as a minimum as follows: Integrated radiation tolerance test, chemical resistance test (submerged condition in deionized water), hardness test and adhesion test of the repair materials. The proper repair coating materials were selected and approved from this test results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.1 s.53
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• pp.69-77
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• 2009

An underwater structure is made to put with serious damage state by special environmental factors. If this damage phenomena persist, as for the structure, it is generated a structural serious problem because of the corrosion of a reinforcing bar and the loss of the concrete cut end. Repair work of an underwater structure is very harder than repair work in land, and it is actual that certification about a maintenance effect is uncertain. And the existing repair method is applied to a structure damaged with you without verification of a repair effect by a foreign reward and experience. In this study, a repair method about an underwater structure was proposed and observed a behavior characteristic and interface failure of an specimens. and comparison analyzed an effect of a proposed maintenance method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.193-194
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• 2019

The purpose of this study is to design the basic mix proportions of antiwashout underwater polymer cement mortar as a repair material. The antiwashout underwater polymer cement mortars are prepared with various mix proportions using three type polymer dispersions without or with antifoamer. From the test results, the whole antiwashout underwater polymer cement mortars can be cast underwater without segregation like plain mortar. It is apparent that the flexural strength of antiwashout underwater SBR cement mortars with antifoamer at polymer- cement ratios of 5% and 10% is higher than that of plain mortar irregardless of a little low compressive strength.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.6
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• pp.77-81
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• 2009

This study was performed to evaluate applicability of patching materials for underwater dam concrete structure. Two kinds of patching materials was investigated. Laboratory experimentals were conducted by workability, compressive strength, bond strength, chloride ion penetration, abrasion resistance. Test results showed that the most performances are relatively good except chloride ion penetration.

• Journal of Ocean Engineering and Technology
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• v.6 no.2
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• pp.113-124
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• 1992

The offshore industry created a need for quality wet weld repairs. Wet welding is a fast method of repair providing sound, structural quality welds. It requires less support equipment than a similar underwater dry weld repair or the alternative mechanical connections. Compared to welds made in air, underwater wet welds are plagued by increased hardness due to rapid quenching by the surrounding water. In this paper is described the experimntal study of improving the cooling rates of wet welds of TMCP steel plate by shielding around weld arc surroundings. The principal results of this experimental investigation can be summarized as follows : By shielding around weld arc surrounding, the cooling rates resulting from wet welds on TMCP steel plate could be lower than that of nonshielded wet welds and the fesibility on high quality of mecanical properties of wet weld on TMCP steel plate was carried out with shielded weld arc surrounding.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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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.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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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.