• Journal of Environmental Impact Assessment
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• v.19 no.1
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• pp.15-28
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• 2010

Because deterioration of air quality and urban heat island directly harm health of citizens, Health Impact Assessment (HIA) and Environmental Impact Assessment (EIA) for urban development projects needs to conduct analysis of their impacts objectively. This study aims to review appropriate methods for assessment of air quality used at each stage of urban development and to investigate prediction and assessment methods of urban heat island. In addition, by evaluating impacts of climate change following supposed urban construction performed in the central area of Korea on public health, it examines usefulness of HIA for urban construction. When urban heat island prediction and HIA method suggested in this study are applied to an imaginary city, they predict urban heat island properly and the impacts of climate changes on public health inside the city could be determined clearly by calculating life-climate index and bio-climate index related with thermal environment from the model.

• Journal of the Korea Concrete Institute
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• v.19 no.1
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• pp.47-56
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• 2007

Recently, tunnels are increasingly constructed in this country with the increased construction of highways, high-speed railways and subways. Shotcrete is one of the major processes in the tunnel construction. Many problems, however, exist in the current shotcrete practice. The purpose of the study is, therefore, to explore the trobles in the current shotcreting practice, and to develop high-quality silica fume shotcrete. For the purpose of security a long-term durability of shotcrete, this study conducted combined deterioration tests. In this study, a combined deterioration test in consideration of a variety of deterioration factors were proceeded. Especially, micro-silica fume that was used frequently in overseas because of a outstanding strength-promotion effect was applied to combined deterioration test, and a long-term durability of shotcrete was investigated according to additions mixing. As a result of test, the shotcrete mixed Micro-silica fume showed a good deterioration quality compared with the other mixes. And is shows that the Micro-silica fume has an outstanding strength-promotion effect and is effective to secure a long-term durability of shotcrete by means of decreasing a deterioration caused by steel fiber mixed.

• Journal of the Korean GEO-environmental Society
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• v.25 no.2
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• pp.5-14
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• 2024

Reinforced concrete bridge decks are the first to be damaged by vehicle loads and rain infiltration. Concrete deterioration primarily occurs owing to the corrosion of rebars and other metal components by chlorides used for snow and ice melting. The structural condition and concrete deterioration of the bridge decks within the pavement were evaluated using ground-penetrating radar (GPR) survey data. To evaluate concrete deterioration in bridges, it is necessary to develop GPR data analysis techniques to accurately identify deteriorated locations and rebar positions. GPR exploration involves the acquisition of reflection and diffraction wave signals due to differences in radar wave propagation velocity in geotechnical media. Therefore, a full-waveform inversion (FWI) method was developed to evaluate the deterioration of reinforced concrete bridge decks by estimating the radar wave propagation velocity in geotechnical media using GPR data. Numerical experiments using a GPR velocity model confirmed the deterioration phenomena of bridge decks, such as concrete delamination and rebar corrosion, verifying the applicability of the developed technology. Moreover, using the synthetic GPR data, FWI facilitates the determination of rebar positions and concrete deterioration locations using inverted velocity images.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.233-240
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• 2000

Nuclear power plant structures may be exposed to aggressive environmental effects than may cause their strength and stiffness to decrease over their service lives, Although the physics of these damage mechanisms are reasonably well understood and quantitative evaluation of their effects on time-dependent structural behavior is possible in some instances such evaluations are generally very difficult and remain novel. The assessment of existing RC containment in nuclear power plants for continued service must provide quantitative evidence that they are able to withstand future extreme loads during a service period with an acceptable level of reliability. Rational methodologies to perform the reliability assessment can be developed from mechanistic models of structural deterioration using time-dependent structural reliability analysis to take earthquake loading uncertainties into account. The final goal of this study is to develop the reliability analysis of RC containment structures. The cause of the degrading is first clarified and the reliability assessment has been conducted. By introducing stochastic analysis based on random vibration theory the reliability analysis which can determine the failure probabilities has been established.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.229-232
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• 1999

Nuclear power plant structures may be exposed to aggressive environmental effects that may cause their damage mechanisms are reasonably well understood and quantitative evaluation of their effects on time-dependent structural behavior is possible in some instances, such evaluations are generally very difficult and remain novel. The assessment of existing steel containment in nuclear power plants for continued service must provide quantitative evidence that they are able to withstand future extreme loads during a service period with an acceptable level of reliability. Rational methodologies to perform the reliability assessment can be developed from mechanistic models of structural deterioration, using time-dependent structural reliability analysis to take loading and strength uncertainties into account. The final goal of this study is to develop the analysis method for the analysis for the reliability of containment structures. The cause and mechanism of corrosion is first clarified and the reliability assessment method has been established. By introducing the equivalent normal distribution, the procedure of reliability analysis which can determine the failure probabilities has been established.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.195-201
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• 2008

When reinforced concrete is subjected to high temperature as in fire, there is deterioration in its properties of particular importance are loss in compressive strength, cracking and spalling of concrete, destruction of the bond between the cement paste and the aggregates and the gradual deterioration of the hardend cement paste. Assessment of fire-damaged concrete usually starts with visual observation of color change, cracking and spalling of the surface. In this paper, it was reported the trends of research and practical use on the Explosive Spalling Properties of the High-Strength Concrete.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1376-1381
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• 2010

In this study, we dealt with an analysis and development of measurement systems for tunnel and slope structures under a high velocity. Deterioration of tunnel and slope structures becomes a critical issue in regard to both safety and economic concerns. Deterioration itself is inevitable, but condition assessment technology and nondestructive evaluation techniques could provide solutions to ensure public safety by means of detecting damage before serious and expensive degradation consequences occur. We reviewed the existing monitoring and maintenance systems of slopes and tunnels and more advanced directions, especially for highways under high-speed vehicles.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.371-374
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• 2003

The degree of changes in mechanical properties of fire-damaged reinforced concrete column depends mostly on sectional geometry, duration exposed to fire, and moisture containment. In order to reasonably assess the deterioration of structural capacity of fire-damaged reinforced concrete column, it is necessary to develop a theoretical model predicting column behavior based on nonlinear heat transfer equation in addition to the traditional mechanics. This research focuses on the development of theoretical model to predict moment-curvature relations of fire-damaged reinforced column. The model is used for the assessment of structural capacity of fire-damaged column in terms of moment-curvature relations and PM interaction curves.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.4
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• pp.101-107
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• 2000

In this study, the Ground Penetrating Radar(GPR) was tested to evaluate the condition of concrete decks. Test results obtained by CPR were compared with values measured from drilled cores and damage mapping by the visual survey. It is shown that GPR can provide highly accurate measurements of layer properties of concrete decks and can map areas of deterioration in bridge decks by dielectric constants. The deck condition can be grouped into categories of "good" or "distressed". The ground penetrating radar data shows promise for producing rapid and accurate condition assessment for bridge decks. And these data can be used to evaluate highway bridge condition and make cost-effective bridge deck rehabilitation by accurately estimating the quantity of deteriorated concrete.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.653-658
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• 1998

In order to provide orange sac for off-season processing of sac-suspended orange juice, orange was treatee into intermediate production of orange sac and segment, stored at 2$0^{\circ}C$ during 3 months for assessment of sac-quality providing various processing conditions. Lowering the pH of syrup and sterilization temperature reduced the deterioration of sac quality in terms of intensity and destruction of sac. Sugar content of syrup had little relation with intensity of orange sac at pH 6.5, whereas in the range of pH 3.0~3.8, the increase of sugar content increased intensity of sac. The storage of segment form maintained better quality than that of sac form. The absorbance of syrup was linearly inverse to sac intensity. The deterioration of sac quality may be related to effulence of some materails in sac. Sac product sterilized at below $65^{\circ}C$ had possibility to be contaminated by microbes.