• Corrosion Science and Technology
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• v.4 no.5
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• pp.171-177
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• 2005

A comprehensive framework for numerical simulation of time-dependent performance change of reinforced concrete (RC) structures subjected to chloride attack is presented in this paper. The system is composed of simplified computational models for transport of moisture and chloride ions in concrete pore structure and crack, corrosion of reinforcement in concrete and mechanical behavior of RC member with reinforcement corrosion. Service-life of RC structures under various conditions is calculated.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.418-421
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• 1996

Carbon Fiber Sheet is very attractive for the upgrading damaged reinforced concrete due to its good tensile strength, handabilbity and resistance to corrosion. This paper discusses the applicability of continous carbon fiber sheet for a reinforcement of existeing reinforced concrete structure located in Pusan. Examples of site data and actual concrete rehabilitation project at slab structure related to construction method used carbon fiber sheet will be given.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.453-458
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• 1996

In reinforced concrete structure, it is very important to secure ductile performance of column because the columns become brittle failure and cause the collapse of an entire structure and the damage of human life. This study is intending to seek the quantity of transverse steels in square reinforced concrete columns which is derived from moment-curvature analysis of cross section about various arrangements of transverse steel and the ratio of axial force and to propose the design method to secure the sufficient ductile behavior subjected to complex loading.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.141-144
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• 1990

In recently, the interest of high strength and flowing concrete, to improve quality and workability of concrete, is gradually increased. In order to make high strength and flowing concrete, many processes may be considered, the water reducing technique using superplasticizer seems to be the most practical, but domestic superplsticizers are not widely used because of economical efficiency, low quality and lack of understanding in construction field. The purpose of this report is to analyze the consumption structure and behavior of domastic acmixtures containing superplasticizer, and to examine about, dessemination of superplasticizer.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.829-834
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• 2002

Recently, research and development for a number of repairing material like an epoxy-based material and polymer-cementitious material as well as anti-washout underwater concrete have been carried out. But, the study on tile materials for the concrete structure exposed to a wetted condition is at a standstill and there are not any suitable reference data at a repairing work for the concrete structure at a splash as well as a structure under severe moisture condition. In this study, the material, called as “ceramic metal”, with an excellent mobility and plasticity as well as with a high bond strength and durability of freezing-thawing resistant properties under any environmental conditions was developed. And, the experimental evaluations for the utility wert widely performed.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.11-14
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• 2003

The purpose of this paper is to offer a base data of specification, so that the strength information of concrete in the structure for irrigation can be rationally determined the coefficient of variation of an existing irrigation structure and the best fit the ready-mixed concrete strength to specified strength $f_ck$. From analysis of concrete cylinders from about 30 numbers in southern Korea, it was concluded that the coefficient of variation of cylinder strength were approximately 5.9%. On the basis of the core strength test data, it was appeared that the average coefficient of variation for the existing irrigation structure can be taken as 17.8% for strength level 21MPa.

• Computers and Concrete
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• v.22 no.1
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• pp.117-122
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• 2018

The use of nanotechnology materials and applications in the construction industry should be considered for enhancing material properties. However, in this paper, the technical and economical assessment of applying silica nanoparticles for construction of concrete structure is studied. In order to obtain the equivalent material properties of the structure, the Mori-Tanaka model is used considering agglomeration of nanoparticles. The effect of using these nanoparticles on mechanical properties of concrete, such as the modulus of elasticity, compressive strength, as well as its indirect effect on armature percentage is investigated. Finally, the price of silica nanoparticles and its effect on the price increase of concrete structure is investigated. The results show that increasing the volume percent of silica nanoparticles up to 10% improves elastic modulus 111% and reduces amateur percentage up to 72%.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.328-333
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• 1996

Concrete can be defective for several reasons, including an inadequate design, material selection of workmanship, failure to appreciate the hazards associated with prevailing enviromental conditions. Concrete can also deteriorate or be damaged in use. Thus, it is necessary to evaluate the safety of existing concrete strucutres. On the basis of these reasons, they must be performed for repair or rehabilitation. Presently, strengthening methods of R/C structure used in Korea, are an enlargement of concrete member, strengthening with steel plate or CFRP on the R/C structure. It has been widely estabilished that strengthening effect of CFRP is superior to steel plate in terms of it's lighter unit weight and higher tensile strength. But there are no construction results of CFRP on the civil R/C structure in Korea. The strengthening design technique with CFRP, it's const겨ction, and it's strengthening effect for deteriorated R/C rahmen bridge is introduced in this paper.

• Journal of the Korean Ceramic Society
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• v.26 no.6
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• pp.729-736
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• 1989

This study aims to reinforce concrete structure by impregnation of molten sulfur. The improved properties of sulfur impregnated concerete were confirmed by compressive strength test and water proof effect. Following variables were adopted to evaluate impregnation parameters ; 1) the effect of water content in concrete structure (0-8%) 2) impregnation time of molten sulfur(0-22hr) 3) impregnation temprature of molten sulfur(13$0^{\circ}C$, 14$0^{\circ}C$). In partial ponding experiments, the concrete specimen of sulfur impregnated by 2wt% yields 1.5 times higher value of compressive strength than that of control one(non-impregnated concerte). In complete ponding experiments, the mortar specimen of slufur impregnated by 12-14wt% yields 2-3 times higher value of compressive strength than that of control one (non-impregnated mortar). From the examination of X-ray diffractions, $\alpha$-sulfur was found in concrete pores. Homogeneous impregation of molten sulfur into concrete pores was also identified with poresize analysis and micrographs of SEM.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.633-636
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• 2006

High-rise and large size buildings require high strength concrete and steel structure as a necessity. However, high strength concrete and steel structure are strong material but have a weakness to high temperature. Therefore, fire protection is a matter that must be considered very importantly in design for structure of high strength concrete and steel. Fire proof board that is existing method for fire proof has relatively low performance in fire protection emphasizes the need of new fire protection material due to the using of in numerable inflammables like plastics. The objective of this study is to understand the fire-resisting performance of newly developed fire protection material for building. This paper describes the results of fire tests using ISO curve that is fire protection regulation for buildings of the newly developed cementitious fire protection coating material applied concrete tunnel lining specimens.