• 자연과학논문집
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• 제19권1호
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• pp.27-35
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• 2008

The importance of microbial activity in the alteration and deterioration of stone and concrete walls has been frequently neglected. Organisms present on stone monuments can include photolithoautotrophs, such as algae, cyanobacteria, mosses, and higher plants. Because of their ability to survive repeated drying and rehydration cycles and high UV levels, the cyanobacteria are particularly important on exposed surfaces. The cyanobactria distributed on the surface of the stone cultural heritages in Gwanschoksa, Nonsan city were investigated. Chlorococcus sp. Aanabaena sp. Gloeocapsa sp Lyngbya sp. Stigomena sp. Synechocystis sp were identified. Haplaosiphon fontinalis and Stigonema turfaceum, which were not recoded is Korea, were also identified. Cells often have thick pigmented sheath in dry, sun-exposed environment and shorter filament, which can be different than that in aquatic systems. Special attention should be paid to production of an adequate DNA database in order to accelerate the rate at which information on the species present in biofilms become available.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.191-192
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• 2018

This study presents the standard methods of diagnosis and repair to prevent and maintain the durability degradation caused by leakage cracks in underground structures in Korea. The third part after the announcement of the existing maintenance plan, The environmental characteristics and leakage condition of underground structures, the causes of deterioration of underground concrete structures, and countermeasures and leakage equipment were described.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.836-841
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• 2005

As gravel roadbed is gradually turn down by repetitive loading of train, lasting work for maintenance and management of track is necessary to reduce the settlement of roadbed and the deterioration of track. Despite of above weak point, gravel roadbed has become a basic structure of roadbed at the present time. But request for new structure of roadbed is recently presented to settle an increased transportation capacity of track, and to solve a shortage of the labor to handle maintenance work of track. Therefore, we begin to research about maintenance-free roadbed like paved track from two years ago. In this study, a series of tests were performed to clarify the characteristics of strength and permeability of concrete specimen, which is the upper part of paved track injected by cement mortar, by type of geotextile and finally to give a basic data for application of geotextile to the lower part of paved track.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2010년도 정기 학술대회
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• pp.766-769
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• 2010

본 논문은 콘크리트 구조물 중 원전구조물에서 열화요인에 따른 미세구조적 변화에 대해서 평가하였다. 이는 원전구조물의 경우 열화현상이 발생하게 되면 일반 구조물에 비해 심각한 영향을 초래하기 때문에 기존의 열화 평가 방법에 의존하기 보다는 미세구조적 관점에서 콘크리트의 열화를 재평가해야 한다. 그에 일환으로 열화 요인 중 동결 융해와 황산염에 대한 미세구조 평가를 실시하였다. 동결융해의 경우, 미세구조적 관점에서의 미세공극의 양이 증가하는 것을 확인하였으나 그 증가 폭이 크지 않음을 알 수 있었으며, 물리적 실험에서도 그 변화가 매우 작음을 확인할 수 있다. 그리고 황산염에서는 초지 침지 구간에서는 플라이 애쉬를 사용한 원전 콘크리트 배합이 콘크리트에 더 유리하게 작용함을 알 수 있다.

• Steel and Composite Structures
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• 제10권4호
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• pp.331-348
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• 2010

Ample research effort has been oriented into developing damage indices with the aim of estimating in a reasonable manner the consequences, in terms of structural damage and deterioration, of severe plastic cycling. Although several studies have been devoted to calibrate damage indices for steel and reinforced concrete members; currently, there is a challenge to study and calibrate the use of such indices for the practical evaluation of complex structures. The aim of this paper is to introduce an energy-based damage index for multi-degree-of-freedom steel buildings that accounts explicitly for the effects of cumulative plastic deformation demands. The model has been developed by complementing the results obtained from experimental testing of steel members with those derived from analytical studies regarding the distribution of plastic demands on several steel frames designed according to the Mexico City Building Code. It is concluded that the approach discussed herein is a promising tool for practical structural evaluation of framed structures subjected to large energy demands.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.493-495
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• 2003

The establishment of the investigation and the maintenance technique is required for preservation of old structures in Japan. This study attempts to diagnose the deterioration status of the historic structures using the thermal infrared camera. In some structures, the difference of the spatio-temporal change was observed in the surface temperature. For example, the cold joint of concrete was examined using this method effectively. As a result of this study, we have found useful guidelines in developing methodology to conduct diagnosis of historic buildings by using thermal infrared camera.

• 한국관개배수논문집
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• 제14권1호
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• pp.67-79
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• 2007

Concrete repair and reinforcement is a complex process, presenting unique challenges very different from those experience in the field of construction. The purpose of this study is to analyze the pattern and mechanism of deteriorations in irrigation and drainage structure. Damage and deteriorated structures are classified with several types. This provides a survey of crack repair methods, including a summary of the procedures that are being used. It is systematically evaluated with the disintegration on irrigation & drainage structure; drainage sluice gate, pumping station, drainage pumping station. Following the evaluation of the irrigation & drainage structure, a suitable repair and reinforcing procedure can be selected based on this report

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.235-236
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• 2019

Waterproofing materials and construction methods have been developed and applied to various construction sites since the past. However, there many cases where the waterproofing performance is not satisfactory, leading to continuous water leakage. It has been observed that a key reason for this is because waterproofing method and material selection is not optimized in terms of the appropriate application area and environmental degradation factors. This paper proposes that future selection of waterproofing methods should consider the following evaluation criteria; 1) waterproof performance evaluation according to site conditions, 2) evaluation of construction method, 3) manufacturing and maintenance of waterproofing systems.

• Structural Engineering and Mechanics
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• 제69권2호
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• pp.163-175
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• 2019

Structural deterioration arises due to aging, environmental effects, deficiencies during design and construction phase, and overloading. Experimental and numerical investigations are carried out in this study to evaluate the performance of control and flexural deficient reinforced concrete (RC) beams under monotonic loading. Three levels of flexural deficiency are considered in this study. After confirming load carrying capacities of control and flexural deficient beams, the flexural deficient RC beams are strengthened with carbon fibre reinforced polymer (CFRP) fabric. CFRP strengthened RC beams are tested under monotonic loading and compared with the performance of control specimen. Further, non-linear finite element analyses are also carried out to evaluate the flexural performance of control, deficient and CFRP strengthened flexural deficient RC beams. There is good correlation between results of experimental and numerical investigations. Numerical approach presented in this study can be adopted for assessing the adequacy of CFRP retrofit measure.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.25-26
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• 2019

The Reinforced concrete structure is deteriorated in durability due to various deterioration factors such as acid, salt, etc., and thus requires repair and reinforcement. In this study, compressive strength and weight change were measured by substituting blast furnace slag with excellent chemical resistance. As a result, the decrease in compressive strength decreased in proportion to the blast furnace slag substitution rate, and in the case of BFS40, the strength increased after sulfuric acid immersion. The weight change also decreased in proportion to the replacement amount.