• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.542-545
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• 2007

The vertical drain method generate the disturbed zone, because the drainage should be penetrated into the in-situ ground. The characteristics of the smear zone generated cause the problems that the coefficient of permeability decreases and the consolidation time anticipated in the design is not properly shortened. In this study, in order to understand such influence, the laboratory test were carried out so as to reasonably determine the coefficient of consolidation in silt. For that procedure, mandrel of a diversity were penetrated into the soil tube with silt, and then the variation of pore water pressure was measured with the pore pressure meter, Then, the range of smear effect on silt was estimated with monitoring data through the laboratory test, and also analyzed with inputting the coefficient of consolidation into the theoretical equation.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.157-166
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• 2012

Most of the roads are paved with impermeable materials such as asphalt concrete and cement concrete, and in the event of heavy rainfall, rainwater directly flows into river through a drainage hole on the pavement surface. This large quantity of rainwater directly spilled into the river frequently leads to the flooding of urban streams, damaging lowlands and the lower reaches of a river. In recent years there has been a great deal of ongoing research concerning water permeability and drainage in pavements. Accordingly, in this research, a porous polymer concrete was developed for permeable pavement by using unsaturated polyester resin as a binder, recycled aggregate as coarse aggregate, fly ash and blast furnace slag as filler, and its physical and mechanical properties were investigated. Also, 3 types of permeable polymer block by optimum mix design were developed and rainfall runoff reduction effects by permeability pavement using permeable polymer block were analyzed based on hydraulic experimental model. The infiltration volume, infiltration ratio, runoff initial time and runoff volume in permeability pavement with permeable polymer block of $300{\times}300{\times}80$ mm were evaluated for 50, 100 and 200mm/hr rainfall intensity.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.6
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• pp.77-83
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• 2001

The purpose of this study is to provide the fundamental material and information for the plant maintenance after rooftop planting through physiochemical characteristics. The characteristics of artificial soils after rooftop planting from 1993 to 1999 was investigated. Fourteen investigation areas were selected from 4 cities(2 areas selected by each year). The analysis of the circumstances of the areas, the physical characteristics, and the chemical characteristics of the soil were conducted. The artificial soil pH ranged 5.26∼7.40 showing that after construction the soil pH tended to decrease. The soil bulk density of the site was lowest in 1999, 0.15g/㎤, and used to increase toward 1993. We found the fact that the soil bulk density increased gradually after rooftop application . The coefficients of permeability of the soils range from 0.016 to 0.052 cm/sec, which seemed to be in good permeability level. The artificial soils had relatively high water moisture capacity of 62.69∼71.36%. The soil organic matter content of the artificial soils ranged from 0.43 to 1.34%. The exchangeable caution concentration in the artificial soil ranged, Na, 2.36∼4.71mg·{TEX}$kg^{-1}${/TEX}, Mg 0.88∼2.84mg·{TEX}$kg^{-1}${/TEX},K 2.97∼9.61 mg·{TEX}$kg^{-1}${/TEX}, and Ca 9.39∼28.23 mg·{TEX}$kg^{-1}${/TEX}. The amount of total N ranged from 0.003 to 0.286% in study sites. Soil chemical properties varied year to year and showed little tend. The research results showed that some characteristics of the artificial soil were changed after rooftop planting, i.e., soil pH and soil bulk density. Soil bulk density had a negative relationship with the coefficient of permeability, showing that the drainage condition might be limited after some period. This study suggests that a diversity of the research in the changes of the plant growth basis on the areas after construction.

• Membrane and Water Treatment
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• v.1 no.3
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• pp.171-179
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• 2010

The transport of selected salts of sulphuric acid (cobalt, copper, iron(II), manganese, nickel and zinc sulphate) through an anion-exchange membrane Neosepta-AFN was investigated in a counter-current continuous dialyzer at various salt concentrations and volumetric liquid flow rates. The basic transport characteristics - the rejection coefficient of salt and the permeability of the membrane - were calculated from measurements at steady state. The salt concentration in model mixtures was changed in the limits from 0.1 to 1.0 kmol $m^{-3}$ and the volumetric liquid flow rate of the inlet streams was in the limits from $8{\times}10^{-9}$ to $24{\times}10^{-9}m^3\;s^{-1}$. Under the experimental conditions given, the rejection coefficient of salts tested was in the range from 65% to 94%. The lowest values were obtained for iron(II) sulphate, while the highest for copper sulphate. The maximum rejection of salt was reached at the highest volumetric liquid flow rate and the highest salt concentration in the feed. The permeability ($P_A$) of the Neosepta-AFN membrane for the individual salts was in the range from $0.49{\times}10^{-7}m\;s^{-1}$ to $1.8{\times}10^{-7}m\;s^{-1}$ and it can be described by the following series: $P_{FeSO_4}$ < $P_{NiSO_4}$ < $P_{ZnSO_4}$ < $P_{CoSO_4}$ < $P_{MnSO_4}$ < $P_{CuSO_4}$. The permeability of the membrane was strongly affected by the salt concentration in the feed - it decreased with an increasing salt concentration.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.288-295
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• 2011

The objective of this study is to develop a proper absorbent-pervious pavement. By using single graded aggregates and SAP, permeability and water absorbability of absorbent-pervious pavement are improved, and also temperature reducing effect is found out. And several tests such as compressive and flexural strength tests, and permeability/water absorption tests of absorbent-pervious pavement are carried out to verify these kind of effects. The compressive and flexural strengths are increased according to decrease of single graded aggregate size, and increase of SAP content. And the volume of water retention and absorbability are increased according to the increase of SAP content and these are also increased in small size of single graded aggregate. And about $20^{\circ}C$ of difference is observed in surface temperature between normal asphalt pavement and absorbent-pervious pavement.

• Advances in concrete construction
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• v.13 no.1
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• pp.101-111
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• 2022

The rapid development of the construction industry in the world causes a rapid increase in the consumption of aggregate resources, which leads to the depletion of existing aggregate reserves. The use of recycled aggregate in the production of concrete and mortar may be a good solution to reduce the use of natural raw materials and to reduce demolition waste in the environment. In this study investigating the use of recycled aggregate in mortar production, mortar mixtures were produced by substituting 0%, 25%, 50% and 100% fine recycled aggregate (FRA) instead of natural aggregate. The effect of 20% and 40% fly ash (FA) substitutes on cement mortar performance was also investigated. Compressive and flexural strength, drying shrinkage, abrasion resistance, water absorption and capillary water absorption were investigated on the produced mortars. The increase in the use of FRA reduced the compressive and flexural strengths of mortars. While the capillarity coefficients, water absorption, rapid chloride permeability and drying shrinkage of the mortars increased with the increase in the use of FRA, the effect of the use of fly ash on the rate of increase remained lower. The increased use of FRA has improved abrasion resistance as well.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.93-100
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• 2005

The purpose of this study is to investigate the physical properties of porous concrete according to the aggregate shape and size which is produced by con crusher and impact crusher. For this purpose, the selected test variables were the aggregate size and shape, the ratio of water to cement and the ratio of paste to aggregate. The results of this study showed that its economic performance and physical properties were improved using the aggregate made by impact crusher. The coefficient of permeability and compressive strength of porous concrete had a close correlationship with the void ratio, and it was suggested as a function of void ratio.

• Journal of the Korean Geotechnical Society
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• v.39 no.10
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• pp.19-26
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• 2023

This research aimed to predict the seepage rate in the base rocks of a concrete face rockfill dam (CFRD) by conducting numerical analysis under various conditions. We examined the relationship between basic grouting and seepage, emphasizing the significance of the permeability coefficient of the grouting material and the rock. Moreover, we observed a decrease in seepage with an increase in the cross-sectional area of the dam. The results of this study provide essential input factors and outcomes of numerical analysis, incorporating various parameters, to inform the design phase. Additionally, our findings offer a dependable approach for calculating a reasonable seepage rate during both operational and maintenance phases.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1C
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• pp.1-10
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• 2011

This paper simulates the piping effect, found levees with large difference in coefficient of permeability within the foundation such as the Gim-po Levee, via centrifuge model test which is a model test. We have also conducted a numerical analysis under the same conditions as the centrifuge model test to compare its results. First, we decided to use the centrifuge model based on the Gim-po Levee, and the tests were executed on a model levee with pore water pressure transducers. We have found that most of the water flows through the permeable layer and causes the piping effect. Via video camera footage, we have found that the piping effect occurred at the toe of the model levee. The characteristic of pressure head distribution, obtained from the pore water pressure transducers, also proves the occurrence of the piping effect. The numerical analysis results also showed the same results as the centrifuge model test. We have simulated the piping effect via centrifuge model test and believe that the centrifuge model test is viable for various tests, predictions and evaluation of the levee problems.

• International Journal of Concrete Structures and Materials
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• v.7 no.3
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• pp.225-238
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• 2013

In this study, a two-layer feed-forward neural network was constructed and applied to determine a mapping associating mix design and testing factors of cement-nano silica (NS)-rice husk ash ternary blended concrete samples with their performance in conductance to the water absorption properties. To generate data for the neural network model (NNM), a total of 174 field cores from 58 different mixes at three ages were tested in the laboratory for each of percentage, velocity and coefficient of water absorption and mix volumetric properties. The significant factors (six items) that affect the permeability properties of ternary blended concrete were identified by experimental studies which were: (1) percentage of cement; (2) content of rice husk ash; (3) percentage of 15 nm of $SiO_2$ particles; (4) content of NS particles with average size of 80 nm; (5) effect of curing medium and (6) curing time. The mentioned significant factors were then used to define the domain of a neural network which was trained based on the Levenberg-Marquardt back propagation algorithm using Matlab software. Excellent agreement was observed between simulation and laboratory data. It is believed that the novel developed NNM with three outputs will be a useful tool in the study of the permeability properties of ternary blended concrete and its maintenance.