• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.48-56
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• 2013

Prestressed concrete (PSC) members are readly available in civil engineering applications due to the convenience of construction and easy of quality control in the manufacturing process of the member. Especially, half-depth precast concrete composite slab, which is one of the PSC flexural members is developed recently using the long-line method. The half-depth precast concrete composite slabs are composed of the precast concrete and the in-situ concrete placed at the site. In this paper, we present the results of experimental investigations pertaining to the pretensioning efficiency and the flexural behavior of half-depth precast concrete composite slab which is made of precast PSC manufactured by the long-line method. In the long-line method, the pretensioned precast member is manufactured simultaneously, by tensioning tendons at once. In addition, we suggest the equation that can estimate the flexural strength of half-depth precast concrete composite slab reasonably by considering the effects of rebar embedded in the precast PSC flexural member.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.21-29
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• 2010

Cathodic Protection has been introduced as a method of protecting metals under the ground or sea from corrosion. Since 1970, it has been applied to reinforced concrete structures as a corrosion protection method. After 1990, it became used around the world, and its usability has been well confirmed. But this method has some problems in terms of construction and economy. To solve these problems, a Cathodic Protection Method using a highly-durable metal spray was developed. First, the specimen was covered with anodic materials (Zn, Al) by using metal spray. The corrosion protection performance was confirmed by measuring the corrosion current of the specimen. Through the experiment, it is possible to confirm that the Cathodic Protection Method using a high metal spray provides effective protection against corrosion to reinforced concrete structures.

• Magazine of the Korea Concrete Institute
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• v.18 no.5 s.94
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• pp.16-22
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• 2006

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.17-18
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• 2010

This study was conducted to develop the design guide of PTCP (Post Tensioned Concrete Pavement). The behavior of PTCP was investigated by performing structural analyses and field experiments. Based on the results, the PTCP design guide was developed by determining the size of concrete slab, design environmental and vehicle loads, and amount and method of longitudinal and transverse tensioning.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.463-464
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• 2010

Pre-tension Girder using Precast Concrete bed System have advantage of simplifying construction process, reducing prestress-loss and cost compared with post-tension Girder. That is because it is possible to produce pre-tension Girder by prefabricated concrete bed in site not factory. This paper present pre-tension girder method using precast concrete bed system and field application.

• Explosives and Blasting
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• v.39 no.1
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• pp.22-35
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• 2021

The number of a industrial plant that must be demolished due to functional and structural deterioration has been increased. There is an increasing application of explosive demolition or explosive demolition combined with mechanical demolition to minimize temporal and spatial environmental hazardous factors created during the process of demolition. In this case study, to demolish the industrial plant foundation, which is a reinforced concrete structure, the explosive demolition technique was conducted. As a result of the explosive demolition, the overall crushing of plant foundation structure was satisfactory, and the explosive demolition was completed without causing any damage to surrounding facilities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.39-47
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• 2016

Repair methods of aging concrete pavement are generally used composite structure pavements, such a composite structure is subjected to a large impact on the mechanical behavior and ensure long-term commonality integrated under vehicle loads, environmental loads of the public in accordance with the bond strength between old and new concrete. A common of bonded concrete overlays that are currently available is Interface arrangements using a variety of equipment to ensure the excellent bond strength between old and new concrete than standard concrete, mixed with a material such as a polymer in order to improve the adhesion with the material itself. However, these method of constructions are being applied, depending on the developer site presents no special specifications apply when a specific application criteria objectively, this is due to the situation of each individual method, which is based on the difficulty in quality control of the site manager. In this study by performing a field test for polymer content via the variables that contribute most significantly to ensure bond strength and the field element core of the interface processing method and materials to ensure bond strength between the old and the new concrete, it was to derive the construction site construction method that can improve the performance of the bond strength through a review of the construction around the correlations and the bond strength according to the effective performance analysis of the conventional surface treatment process and variation of polymer volume fraction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.131-136
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• 2013

The purpose of this study is to establish the flexural strengthening method of the concrete members. To accomplish this objective, a total of seven concrete beams were tested. From this study, it is found that the initial flexural stiffness and strength of the beams reinforced with NSM CFRP strips were significantly improved compared to the beam without CFRP strip. Failure of the beam reinforced with NSM strips is initiated by failure of NSM strips, eventually sudden explosive compressive failure in the loaded region. This strengthening method combined with NSM CFRP strips and high performance mortar for concrete cover recovery is evaluated by a good strengthening method for the strength, durability and good appearance of concrete structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1117-1123
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• 2016

Roller-Compacted Concrete Pavement (RCCP) is a type of pavement that shares conventional concrete pavement material characteristics and asphalt pavement construction characteristics. Even though RCCP is compacted in the same way and have similar aggregate gradation to asphalt pavements, its materials and structural performance properties are similar to those of conventional concrete pavement. With cement hydration and aggregate interlock, Roller-Compacted Concrete or RCC can provide strength properties equal to those of conventional concrete with low cement content. Therefore, compaction ratio of RCC can highly influence on its strength. In general, 95% of compaction ratio is required for proper strength development. RCC strength can be highly influenced by compaction energy which depends on compaction equipment and compaction method. Therefore, it is necessary to analyze the relationship between compressive strength and compaction ratio of RCC. RCCP specimens were produced at different compaction ratio by using different compaction methods and energies. The compaction ratio was defined by the ratio of the specimen's dry density and its maximum dry density. The maximum dry density was obtained from Modified Proctor test. 28 days compressive strength corresponding to each compaction ratio case was tested. Finally, the relationship between compressive strength and compaction ratio can be analyzed. For application of roller-compacted concrete in domestic construction site, the relationship is important for field compaction management.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.302-305
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• 2007

현재 통신용 강관전주는 상, 하로 2 분할된 강관을 조립하여 대부분 사용하고 있다. 콘크리트전주에 비해 가볍고, 길이가 짧기 때문에 도심지 등 협소한 지역에서도 시공이 가능하며 특히 소규모 인력으로 시공이 가능하다. 하지만 전주의 단면이 작아 별도의 기초 보강을 하지 않고서는 지반의 지지력이 부족하여 전주가 기울어지거나 전도되는 현상이 빈번히 발생하고 있으며, 또한 운반을 용이하게 하기 위하여 2 분할한 강관의 조립 부분에서의 꺽임 현상이 발생하여 도시 미관을 해치고 있는 실정이다. 통신전주의 안정성을 확보하기 위해서는 전주 자체가 보유한 강도를 발휘할 수 있도록 충분한 지반지지력이 확보되어 있어야 한다. 강관전주의 휨강도 실험 및 현장 지반지지력 실험을 통해 충분한 지반지지력을 확보할 수 있는 공법을 도출해 내고, 현재 강관전주의 지반지지력 보강을 위해 사용하는 콘크리트블록 설치 방식이 아닌 시공 편리성 및 안정성을 개선한 기초콘크리트 방식을 제시하고자 한다.