• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.814-817
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• 2004

Deterioration due to de-icer salt occurs in practice in concrete pavement, dike, barrier and similar structure. This paper reports the results of effect of de-icer salt on. durability of concrete structure in winter. To protect concrete structure from damage by de-icer salt in winter, the exposure test was performed using three countermeasures such as increase in design strength upto $350kg/cm^2$, application of ggbf slag powder, and concrete sealer. Of these, the method of increase in design strength upto $350kg/cm^2$ showed better durability for deterioration by de-icer salt.

• Journal of Power Electronics
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• v.18 no.2
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• pp.456-466
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• 2018

This paper introduces the development of a de-icer based on a full-bridge modular multilevel converter (FMMC). The FMMC can generate a wide range of DC voltages owing to its modularity, scalability, and redundancy, which makes it suitable for ice-melting applications. First, operating principles and voltage ranges are analyzed when FMMC is applied as a mobile de-icer. Second, two new startup strategies, constant modulation index and constant power startup strategies, are proposed. Third, the main control strategies of the de-icer are proposed. Fourth, a novel rated-current zero-power test scheme is proposed to simplify test conditions. Finally, a 10 kV 1.5 kA mobile MMC de-icer is designed and built, and experiments are carried out to validate the proposed startup, control strategies, and rated-current zero-power test scheme.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.523-526
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• 2005

In order to traffic safety during winter season, snowfall and cold area has been spread the deicing chemicals, and the spraying amount is increasing every year. Use of deicing chemicals has been and will continue to be a major part of highway snow and ice control methods. Chloride-containing chemicals such as calcium chloride or rock salt are main deicers for the road. Extensive use of chloride deicers is, however, the source of substantial cost penalties due to their corrosive action and acceleration to deterioration concrete structures. Deterioration due to de-icer salt occurs in practice in concrete pavement, dike, barrier and similar structure. This paper reports the results of effect of de-icer salt on durability of concrete structure in winter. To protect concrete structure from damage by de-icer salt in winter, the exposure test was performed using three methods such as increase in design strength upto 32MPa application of granulated blast furnace slag powder, and concrete sealer. Of these, the method of increase in design strength upto 32MPa showed better durability for deterioration by de-icer salt.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.221-224
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• 2005

In order to traffic safety during winter season, snowfall and cold area has been spread the deicing chemicals, and the spraying amount is increasing every year. Use of deicing chemicals has been and will continue to be a major part of highway snow and ice control methods. Chloride-containing chemicals such as calcium chloride or rock salt are main deicers for the road. Extensive use of chloride deicers is, however, the source of substantial cost penalties due to their corrosive action and acceleration to deterioration concrete structures. Deterioration due to de-icer salt occurs in practice in concrete pavement, dike, barrier and similar structure. This paper reports the results of effect of de-icer salt on durability of concrete structure in winter. To protect concrete structure from damage by de-icer salt in winter, the exposure test was performed using three methods such as increase in design strength upto 35MPa application of granulated blast furnace slag powder, and concrete sealer. Of these, the method of increase in design strength upto 35MPa showed better durability for deterioration by de-icer salt.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.548-555
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• 2015

This paper aims to estimate the service life of the target bridge structures subjected to chloride ingress from de-icer, which is used for safety of vehicles in winter, by investigating the chloride ingress into concrete. In this study, the 10-year-old bridge structures were investigated by measuring the chloride along the depth from the exposed surface to derive the surface chloride concentration and the diffusion coefficient for the prediction of service life. The service life of each measured point on the structures were estimated with the surface chloride concentration and the diffusion coefficient by using Life-365 software. As a result, it was estimated for all measured points to have over 100-year service life. Furthermore, the diffusion coefficient and the service life from the measured data were compared to another method calculated with the concrete mix, considering the time dependency of diffusion coefficient.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.6
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• pp.29-36
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• 2008

This study examined the de-icing agents' stresses on Pinus strobus and Pinus thunbergii by chlorophyll fluorescence analysis. The assumption of this study was that photosynthetic efficiency was changed by de-icing agents applied onto highways in winter by altering the concentration of the de-icier, types of de-icer and leaf surface coating liquid application. The practical purpose of this study was to investigate the de-icing gents stresses on Pinus strobus by the highway area where de-icing agents were used frequently and to discover out minimizing stratages to prevent further damages. or this simulation study, a sample plot was established in Bogae-myeon, Anseong, Gyeonggi-do and Pinus strobus and Pinus thunbergii were planted for the examination in April, 2005. Five types of de-icing agents - NaCl, $CaCl_2$, T product(NS40:low cWoride de-icer type), NaCl+$CaCl_2$ and T product+$CaCl_2$ - were selected and the their concentration was altered to 0%, 5%, and 9%. Five types of de-icing agents were applied to both trees treated by a leaf surface coating liquid and trees not treated by leaf surface coating liquid. For the fluorescence analysis, the leaf surface coating liquid, which was diluted by 10 times, was sprkinkled onto the two tree species three days prior to gathering samples. Sample leaves from the two tree species were gathered at 10 o'clock in the morning of mid-August, 2006 and brought to the laboratory within three hours to be dipped in different concentrations (0%, 5%, or 9%) of the five de-icing agents for two minutes. Then the eaves were placed on the filter paper dipped in each solution on a petri dish, sealed with polyethylene film and kept in a growth chamber at $22^{\circ}C$ for 72 hours. Out of the growth chamber, the leaves were treated with a chorophyll fluorescence reaction analyzer for 30 minutes to measure the initial light acceptance rate(Fo), maximum light acceptance ate(Fv/Fm), light acceptance usage(F' q/F' m) and optical electron delivery coefficient(qP). As a result, Pinus strobus' initial light acceptance rate(Fo) decreased as T product and NaCl increased in concentration, and $Cal_2$ did not reduce much with the eaf surface coating liquid application. Maximum light acceptance rate(Fv/Fm) and light acceptance usage(F' q/F' m) decreased sharply as T product and NaCl increased in concentration and NaCl+$CaCl_2$ and T product+$CaCl_2$ did not reduce much with leaf surface coating liquid application. Optical electrons delivery coefficient (qP) decreased as T product increased in concentration on trees without the leaf surface coating liquid application and all other de-icing agents did not show much reduction. As for Pinus thunbergii, the initial light acceptance rate(Fo) decreased as T product increased in concentration, but the maximum light acceptance rate(Fv/Fm) was not reduced much by changes in concentration. light acceptance usage(F' q/F' m) decreased as NaCl increased in concentration and optical electron delivery coefficient(qP) decreased as NaCl increased in concentration in both with and without leaf surface coating liquid application. In conclusion, it was possible to plant Pinus strobus if spraying leaf surface coating liquid or cleaning deicing salt to prevent the damage caused by deicing agents was more economical than replacing the trees. If not, it was better to plant Pinus thunbergii. Another way to decrease the deicing gents stresses of landscape plants would be planting the trees further away from the roads even though it might take longer period to display its planting functions.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.663-666
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• 2005

Chloride attach is one of the main factors which cause the deterioration of structures. In the case highway bridges, de-icer salts very significantly increase the surface scaling due to frost action. The deteriorated concrete is subject to experience degrading of durability under chloride attach environment. In this study, diagnosis report of 147 bridges is investigated and core sample of 21 bridge decks is examined and analyzed. The results show that the cover of decks concrete is required more than 8cm for retaining bridge lifetime over 30 years.

• Journal of Preventive Medicine and Public Health
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• v.41 no.2
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• pp.69-73
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• 2008

To curb a rapid increase in expenditures for pharmaceuticals, the Korean government introduced a positive list system and a negotiation process for drug prices at the end of 2006. Economic evaluation of pharmaceuticals has begun to have a pivotal role in the listing and pricing of drugs for the Korean National Health Insurance. There are some points to discuss regarding the use of economic evaluation in the listing and pricing in the context of the Korean system. First, the listing and pricing processes have been fragmented, evoking complaints from pharmaceutical companies and delaying the access of new drugs to patients. Second, there is a concern that the positive list system may limit the range and availability of drugs for patients to choose for treatment. Third, the time schedule for de-listing of existing drugs may not be realistic. Fourth, it is not always easy to provide reliable evidence of cost-effectiveness due to a lack of materials. Fifth, there is no consensus on the range of the ICER (incremental cost-effectiveness ratio) acceptable to the Korean society. In conclusion, in the near future, it will be necessary to evaluate the achievements that the economic evaluation has provided to the Korean society.

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.25-34
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• 2016

OBJECTIVES : This is a basic research for the domestic production of airport-airside deicers. This research selected basic materials for deicers appropriate for the pavement of domestic airports by evaluating the deicing performances of basic materials used in international-standard airport deicers and their impacts on pavements. METHODS : Laboratory investigation was conducted to evaluate the asphalt surface tensile strength, concrete scaling impact, ASR impact, and deicing performances of sodium formate (NaFm), potassium formate (KFm), sodium acetate (NaAc), and potassium acetate (KAc), which are the basic de-icing materials commonly used at international airports, approved by the FAA. In addition, the analyses were also performed on the airside deicer urea, which is currently used in domestic airports. RESULTS : Laboratory investigation confirmed that sodium formate, potassium formate, sodium acetate, and potassium acetate had superior surface tensile strength, concrete scaling impact, and deicing performance compared to airside urea, but they also had greater impacts on concrete ASR. Among these materials, sodium formate had the best asphalt surface tensile strength, concrete scaling impact, and deicing performance, while also having the greatest impact on ASR; hence, mitigation plans for ASR were needed, if it were to be used as airport-airside deicer. CONCLUSIONS : It is necessary to consider additional additives to prevent ASR of concrete pavements when developing airport-airside deicers using sodium formate, potassium formate, sodium acetate, and potassium acetate.