• Resources Recycling
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• v.17 no.1
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• pp.3-11
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• 2008

The treatment of domestic municipal solid waste has inclined to incineration process instead of disposal in landfills. So, the amount of ash generated by incineration of municipal solid waste is gradually increased. The incineration ash divides into bottom ash and fly ash. The bottom ash which accounts for about 90% of the incineration ash consists of ceramics, glasses and metals. And it can be used as the recycling product by the stabilization process. For example, the bottom ash is used as secondary building material or for other similar purposes such as road sub-bases and noise barrier in USA, Europe and Japan. But, the stabilization-treatment technique of bottom ash sti11leaves much to be desired in Korea. Thus, the domestic study of recycling about bottom ash must be improved through investigation about the chemical property and technique of stabilization.

• Atmosphere
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• v.34 no.2
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• pp.217-231
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• 2024

The Korea Integrated Model (KIM)-based real-time volcanic ash dispersion prediction system, which employs the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, has been developed to quantitatively predict volcanic ash dispersion in East Asia and the Northwest Pacific airspace. This system, known as KIM-HYSPLIT, automatically generates forecasts for the vertical and horizontal spread of volcanic ash up to 72 hours. These forecasts are initiated upon the receipt of a Volcanic Ash Advisory (VAA) from the Tokyo Volcanic Ash Advisory Center by the server at the Korea Meteorological Administration (KMA). This system equips KMA forecasters with diverse volcanic ash prediction information, complemented by the Unified Model (UM)-based HYSPLIT (UM-HYSPLIT) system. Extensive experiments have been conducted using KIM-HYSPLIT across 128 different volcanic scenarios, along with qualitative comparisons with UM-HYSPLIT. The results indicate that the ash direction predictions from KIM-HYSPLIT are consistent with those from UM-HYSPLIT. However, there are slight differences in the horizontal extent and movement speed of the volcanic ash. Additionally, quantitative verifications of the KIM-HYSPLIT forecasts have been performed, including threat score evaluations, based on recent eruption cases. On average, the KIMHYSPLIT forecasts for 6 and 12 hours show better quantitative alignment with the VAA forecasts compared to UM-HYSPLIT. Nevertheless, both models tend to predict a broader horizontal spread of the ash cloud than indicated in the VAA forecasts, particularly noticeable in the 6-hour forecast period.

• Nuclear Engineering and Technology
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• v.44 no.3
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• pp.331-342
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• 2012

Since the opening of the Shin-Kori #1,2 in 2005, fly ash mixed concrete has been used for NPP concrete structures under construction in Korea with the aim of preventing aging and improving durability. In this paper, the quality suitability of fly ash manufactured in Korea is assessed and the basic physical properties of fly ash mixed concrete and its durability against primary causes of aging are verified through experimental methods. Because of the internal structure filling effect from the pozzolanic reaction of fly ash and the resulting improvements in mechanical performance in such areas as strength and salt damage resistance, the durability of fly ash mixed concrete is shown to be superior. It is judged that this result can be applied in measures not only for improving the safety of NPP structures in operation in Korea but also for implementing effective structure life management should extending the life of structures be needed in the future.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.99-102
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• 1999

In the study, the effect of the replacement content(20, 40, 60, 80%) and particle fineness and the chemical activator of the fly-ash on the flow and strength development of mortar was investigated. We found that the higher raito of the fly-ash replacement produced the lower the mortar strength and the higher fineness of the fly-ash yielded the higher strength. Also, we used Na2SO4 as activator of fly-ash to rise compressive strength mortar. The result as follows: the fly-ash mortar which stimulated by chemical activator, was higher strength development at early than the fly-ash mortar without chemical activator. But in the late age, the result indicated adversely.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.89-92
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• 1999

The purpose of this study is to evaluate the capability to use with cement admixture materials because Paper Sludge Ash consists of Si, Ca and Al which are chief content in Pozzolan. For the derivation of Pozzolanic reaction in Paper Sludge Ash, it is measured compressive strength on cement mortar which is replaced mixing of Paper Sludge Ash and inorganic admixture ; ie, gypsum, lime and slaked lime, regularly. In the result of test, the strength decrease remarkably when cement is only replaced with Paper Sludge Ash, but the strength is almost equal when cement is replaced with Paper Sludge Ash is mixed with inorganic admixture material in proportions of 5~15%. Consequently, It is possible to use Paper Sluge Ash with admixture materials of cement.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.783-789
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• 2003

This study was conducted to reuse the rice straw ash as washing agent for oil contaminated soils. The results are summarized as follows. The physical characteristics of rice straw before and after burning were as follows ; In case of burning rice straw 1g, the rice straw ash was generated 0.14g and pH was changed neutrality into alkali(pH 10.9) and specific surface area was increased to five times and particle distribution was corresponded to fine silt.(under 0.05mm) The physical characteristics of rice straw ash were Carbon 10.9%, Hydrogen 1.5%, Oxygen 23.4%, Nitrogen 5.2%, Sulfate 1.2% and chemical characteristics were Si 189.2ppm, Ca 10.2ppm, Mg 4.7ppm. Oil cleanup ratio by pH variation were about 40∼50% of initial concentration of oil by pH 10∼11. As the result of cleanup comparative experiment, the rice straw ash was about 20∼30%, the tritonX-100 about 40∼50% of washing efficiency, and then in the future it will be possibility of substitute washing agent.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.57-60
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• 2002

Recently, the coal ash production has been increased by increase of consumption of electric power. So it is important to find a reclaimed place and treatment utility for treating coal ash. Accordingly, in this study we performed an experimental study to compare and analyze the Properties of concrete according to W/C and bottom ash replacement ratio. As a result of this study, it was found that the bleeding content was decreased according to decrease of W/C and increase of bottom ash replacement ratio, and the compressive strength of concrete using bottom ash was similar to plain concrete(replacement ratio 0%).

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.105-110
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• 1998

The purpose of this was to examine the used of fly ash as a type of construction material. In this paper the results from a recent study on development of a cement composite utilizing relatively large amount of fly ash are presented. The flowable fly ash-cement sand composite was investigated for strength and flowability characteristics. The independent variable considered were: fly-ash content, sand content, and ratio of water to cementitious materials. Results of this study show that high volume fly-ash composite can be proportioned to obtain 10~15kg/$\textrm{cm}^2$ compressive strength at 28 days. For applications requiring strength between 10kg/$\textrm{cm}^2$ and 15kg/$\textrm{cm}^2$, the mixture with fly ash-cement ratio of 5.6 and sand-cement ratio of 28 with relatively high water content may be used. Slump was held at 25$\pm$1cm for all mixtures produced compressive strength at 28 days were found to range from 5kg/$\textrm{cm}^2$ to 13.7kg/$\textrm{cm}^2$.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.699-704
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• 2002

Recently, the coal ash production has been increased by increase of consumption of electric power. So it is important to find a reclaimed place and treatment utility for treating coal ash. Accordingly, in this study we performed an experimental study to compare and analyze the properties of concrete according to W/C and bottom ash replacement ratio. As a result of this study, it was found that the bleeding content was decreased according to decrease of W/C and increase of bottom ash replacement ratio, and the compressive strength of concrete using bottom ash was similar to plain concrete(replacement ratio 0%).

• Journal of the Korea Concrete Institute
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• v.11 no.5
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• pp.41-49
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• 1999

This study dealt with the applicability and quality control of the concrete using fly ash produced in combined heat power in a construction site. Firstly, chemical and physical characteristics of the fly ash produced in combined heat power plant re analysed. Also, after investigating the properties of flesh and hardened concrete through various experiments, the fly ash concrete was placed in depositing construction in Ulsan Petrochemical Service Co. This field application was focussed on the quality control system in the site as production, placing and curing of concrete. As the result of this study, the quantity of CaO in the fly ash is relatively high based on the chemical analysis. The fly ash concrete showed slumping maintenance and high viscosity properties in the optimal mixing conditions (W/B:44~45%, S/a:$45\pm$2%, W:185kg/m). And, quality control and assurance of the fly ash concrete in actual site were verified by various testing methods.