• Geotechnical Engineering
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• v.12 no.1
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• pp.73-86
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• 1996

In this study, the possibility of the utilization of coal ash as earthwork materials is investigated. For this purpose, some laboratory experiments were carried out. The samples used in these tests are fly ash(FA), bottom ash(BA), coal ash dropped into ash pond(FA:BA=8:2), and mixed coal ash(FA:BA=5:5), which were discharged as a by-product at Yong-Yeul thermoelectric power plant, and general road filling materials. And for the deformation analysis of coal ash reclamation ground, several hyperbolic model parameters were determined by triaxial compression test. As a result of this study, coal ash has excellent engineering properties such as strength parameters comparing with general soils of the same grain size, especially in case of being used as backfill materials and reclamation materials on soft ground, and coal ash is superior to general earthwork materials in engineering properties becasuse of self hardening behaveiour, light weight property, etc.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.75-81
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• 2018

At present research on mining backfill materials is being carried out to prevent ground subsidence and breaking by underground cavern of exhausted mines. However, backfill materials can cause secondary environmental issues such as ground pollution. To solve these issues, liner and cover materials are constructed before backfill materials constructed, to inhibit toxic substances form moving to the surroundings. Liner and cover materials, however, should have an accelerating performance after construction and when the accelerating performance is degraded, the work efficiency can be lowered, and the construction cost can be increased, by many rebound content. Therefore, this study develops mining liner and cover materials, and evaluates their accelerating performance and physical properties of liner and cover materials by types and content of accelerating agent. In case of aluminate accelerating agent, it is mixed with more than 5% of liner and cover materials(binder/ratio); thus an accelerating performance satisfying Korean Industrial Standards(KS) occurs, and in case of alkali-free accelerating agent, when it is mixed with more than 7%(binder/ratio), accelerating performance satisfying KS occurs. The more the accelerating agent capacity increases, the more compressive strength decreases. In addition, it is confirmed that compressive strength of aluminate accelerating agent is more degraded than compressive strength of the alkali-free accelerating agent. It is also confirmed that drying shrinkage stability of the alkali-free accelerating agent is better than the drying shrinkage stability of the aluminate accelerating agent.

• Journal of the Korea Institute of Building Construction
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• v.21 no.2
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• pp.141-148
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• 2021

In this study, the characteristics of the cement mortar replaced with fly ash and ground granulated blast furnace slag generated during circulating fluidized bed combustion method and pulverized coal combustion process were investigated. As a result of the study, when mixed with circulating fluidized bed combustor fly ash and pulverized coal combustion fly ash, it is advantageous not only in terms of strength development but also in terms of durability. The circulating fluidized bed combustor fly ash contributes to the improvement of initial reactivity, and the pulverized coal combustion fly ash is involved in long-term strength development through pozzolanic reaction. Therefore, it can be seen that the mixed use of circulating fluidized bed combustor fly ash and pulverized coal combustion fly ash acts as a complementary factor for cement mortar substituted with ground granulated blast furnace slag.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.6
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• pp.645-653
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• 2021

Biopolymer is a general concept for high molecular compounds produced by living organisms. Among them, the xanthan and β-glucan, which are organic polymer mixture produced by micro-organisms, are mainly used to increase the viscosity of a substance. And diluting in water and mixing with sand or clay can increase compressive strength and shear strength. In this study, mixed soil prepared by mixing soil with xanthan and beta-glucan based biopolymers specially developed for the purpose of increasing soil strength was applied to the river bank revetment, and changes during winter were measured using ground LiDAR. As a result of analyzing winter changes in major sections using three-dimensional point cloud data obtained through ground LiDAR, there were no changes to the extent that it was difficult to confirm with the naked eye in the two sections coated with biopolymer blended soil. However, soil loss due to Rill erosion was confirmed in the natural embankment section where biopolymer blended soil was not used.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2779-2788
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• 2012

The housing market is now difficult because of excess of the increase rate of housing and long-term recession but high-rise mixed-use buildings can mix residential facilities with various demand facilities focusing and they have the advantages to secure open space and excellent view by high-rise apartment. But there are problems by hindrance of skyline formation and height of buildings. Therefore, the purpose of this study is to suggest the height standard and the slenderness ratio to location types of Mixed-use Residential Tall buildings. For the method of the study, term arrangement through literature search and the precedent research survey were first done, the level of urban design and the details related to the height of buildings were done as the case research focusing on the 16 cases in Seoul. The following results were drawn by suggesting the height standard and the slenderness ratio by location type based on them. First, the height of mixed-use building by location type in the level of urban design gets higher starting from the secondary center of the city and can be suggested as from less than 150m to more than 200m. Second, the slenderness ratio shall be planned as more than 1:3 because the area of the ground level of mixed-use building is large unlike Mixed-use Residential Tall buildings and visual passage shall be placed so that unity of openness and group formation will be planned. Third, for the height related to Mixed-use Residential Tall buildings, amendment of the special architectural district system and the special law related to super high-rise buildings shall be enacted.

• Journal of the Korean GEO-environmental Society
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• v.11 no.4
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• pp.25-31
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• 2010

The amount of dredging clay will be greatly increased by the eco-rive project and port development in Korea. Geotechnical engineers have thrown their efforts into the new ways for effective re-uses of the dredging clay such as the material for reclamation, and so on. However, very high initial water content and low strength causes unexpected difficulties in the aspect of trafficablility or time for consolidation. Therefore, the injection of cement stabilizer is used as one of ways to improve reclaimed ground. However, it also makes an argument by heavy metal from cement stabilizer. In this paper constant rate of strain consolidation test and normal consolidation test were performed to investigate behavior characteristics of the consolidation about soil-cement include lean mixed cement to reduce the environmental loads by the cement. The experimental results of consolidation characteristics about soil-cement include lean mixed cement influenced by mixing ratio. Especially it was observed that mixing ratio of 4%~6% leads not only the reduction of consolidation settlement, but time for consolidation.

• Korean Journal of Clinical Pharmacy
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• v.11 no.1
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• pp.13-18
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• 2001

Omeprazole is usually administered as encapsulated enteric-coated granules and enteric-coated tablets because of its acid-labile nature. For children and patients who can not swallow, it can be mixed with water or other liquid after a capsule is opened or a tablet is crushed. This study was performed to compare omeprazole liquid formulations of tablet and capsule Omeprazole 20 mg capsule containing enteric coated granules was opened and 20 mg entric-coated tablet was ground to be mixed with sodium bicarbonate solution, orange juice or water. Each liquid formulation was poured into dissolution tester, mixed with first solution (artificial gastric juice; pH 1.2) for two hours, then with second solution (artifical enteric juice; pH 6.8) for thirty minutes. pH was measured periodically for two and half hours. Samples were drawn periodically, mixed with lansoprazole as an internal standard, and injected to HPLC. As results, pH of sodium bicarbonate solution of omeprazole was significantly higher than that of orange juice or water in first solution (6.2-7.4 vs. 1.2, p<0.005). At 150 min, concentrations of omeprazole in three diluents with granules and in sodium bicarbonate solution of tablet powder sustained significantly higher than in other solution of tablet powder (p<0.001). In conclusion, enteric-coated granules from capsule with three diluents and powder from tablet in sodium bicarbonate solution was stable during dissolution test, which would be appropriate and recommended for patient who can not swallow solid preparations.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.85-91
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• 2014

In this study, the water quality purification of new medias which were NPS media, hyugato, mineral stone, charcoal for applying soil media of Integrated Management Practices (IMPs) of Low Impact Development (LID) were evaluated. The influent concentrations of COD, T-N, and T-P were 117.8 mg/L, 17.1 mg/L, and 2.062 mg/L, respectively. The infiltration capacities of NPS media, hyugoto, mineral stone, charcoal, and gravel were $7.1{\times}10m/s$, $7.3{\times}10^{-5}m/s$, $7.9{\times}10^{-5}m/s$, $6.0{\times}10^{-5}m/s$, respectively. All media meet criteria of infiltration capacity as surface soil layer at IMPs which is over $1.0{\times}10^{-5}m/s$. Maximum removal rates of COD, T-N, and T-P occurred at Charcoal with 98 % of COD removal rate, NPS with 78 % of T-N removal rate, and hyugato with 75 % fo T-P removal rate, respectively. For more high removal efficiency of all water quality item, the mixed media which is 4.5(NPS media): 1(charcoal) : 4.5 (hyugato) as volume ratio was evaluated. The infiltration capacity of mixed media was $7.9{\times}10^{-5}m/s$ and met the criteria of infiltration as surface soil layer. The water quality removal efficiencies of mixed media were very high with showing 70 % for COD, 85 % for T-N, and 71 % for T-P. The mixed media could purify the water quality of surface runoff and was recommended to used at the LID site of ground water quality problem.

• Journal of the Korean GEO-environmental Society
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• v.3 no.4
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• pp.67-79
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• 2002

The purpose of this study is to present criteria of selection of optimum grout materials through analyzing the limitation of permeability of each materials(MSG-N, OPC), in various ground conditions by comparing presentation of strength and permeability of MSG method and LW method(or SGR method). To do that, physical and chemical characteristics of grout materials were analyzed and compressive tests of homogel, mixed coagulation materials and hardening materials in certain mixing ratio, and of milk paste. In addition, permeability tests for each ground soil, each injection pressure, and each materials in combined stratum were performed with massive chamber. The results of tests showed that ultra fine grout materials like grout of MSG is necessary to construct effective grouting in sand and silty sand ground. Also, it is expected to become chemical grouting guide data to layout construction engineers because presented proper injection pressure by kind of object ground in case using ultra-fine grout material.

• Journal of Environmental Science International
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• v.11 no.12
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• pp.1291-1298
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• 2002

To utilize coastal aquaculture ground bottom sediment in which concentrations of harmful pollutants are low and organic content is high as an organic fertilizer alkaline stabilizers such as CaO, Oyster shell, Mg(OH)$_2$ were added to the bottom sediment organic additives of livestock or food wastes. Nutritive qualities of crude fertilizers were measured to examine effects of alkaline stabilizers and organic waste additions. The Mg(OH)$_2$-added crude fertilizer had significantly lower total carbon(T-C) and nitrogen(T-N) content, reflecting the dilution effect due to great amount of Mg(OH)$_2$ addition. However, the addition of oyster shell had no significant effect on the T-C and T-N content of the fertilizer. $P_2O_5$ and $K_2$O content was considerably higher in the mixed sample of aquaculture ground bottom sediments and livestock wastes than in the mixture of the sediments and food wastes, resulting from higher $P_2O_5$ and $K_2$O content in livestock wastes. Addition of Mg(OH)$_2$ increased the content of MgO In the crude fertilizer but significantly reduced the content of other nutritive elements such as $P_2O_5$, $K_2$O and CaO. Addition of oyster shell as an alkaline stabilizer seemed to have the advantage of saving time and expenses far dryness due to its role as a modulator of water content. Moreover, additions of effect Mg(OH)$_2$ decreased the concentrations of heavy metals in the fertilizer by the dilution while additions of oyster shell had no influence on heavy metal concentrations in the fertilizer.