• Journal of the Korea Concrete Institute
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• v.11 no.4
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• pp.13-20
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• 1999

Recently, the study for practical construction application no recycled aggregate concrete is actively being proceeded, on the purpose of technical development for recycling on the construction waste concrete occurred at the time of destruction of building construction by the rapid increase of building wastes and exhaustion of natural aggregates. But, the durability of investigation with all sorts of fluidity and engineering property for application recycled aggregate concrete to practical construction must be done at the same time. Especially, because of the real condition for chemical attack of concrete construction by the acid rain, acidification of soil, deepening of air pollution and dirty water etc. being come to the fore a serious problem, the study on the chemical soundness of concrete durability must be accompanied. This study is composed as: I series: Analysis for chemical soundness of aggregates. II series: Analysis for chemical soundness of natural and recycled aggregate concrete against $Na_2$$SO_4$ solution in drying and wet curing condition ($at20~80^{\circ}C$).

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.901-904
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• 2006

The government makes efforts to expand the recycling activities of construction waste soil and to increase the usage of recycled aggregate. Accordingly, it has defined the compulsory usage and quality standard by usage of recycled aggregate. To satisfy these efforts requires both technology to produce recycled aggregate which meets the required quality and companies with the technology. Therefore, it requires to review a current status of facilities at the companies which deal with construction wastes. The companies dealing with construction wastes gradually produce the high quality of recycled aggregate. In particular, companies which has over 3-stage processing system for waste concrete continue to increase and means to remove foreign substances are gradually improved.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.27-35
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• 2021

This study examined the possibility of reutilization of soil reclaimed from contaminated sites after completing remediation. The current status of soil remediation methods in Korea was reviewed and physicochemical properties of soil before and after remediation processes were examined to access the recycling possibility of reclaimed soils based on Recycling Aggregate Quality Standard. The most commonly practiced soil remediation techniques are soil washing, land farming, and thermal desorption. These techniques tend to deteriorate various soil properties including electrical conductivity(EC), organic matter content(OM), available P₂O₅, and cation exchange capacity(CEC). Evaluation of the properties of soil retrieved after each remediation process indicated soil washing may yield the most suitable soil for use as a filling, covering, back-filling, road pavement, and blocking materials, In addition, the soils reclaimed from land farming and thermal desorption have potential utility as a filling, covering and road pavement materials.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.29-34
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• 1987

This experiment was designed to find out the effects of soil conditioner, Polyacrylamide (PAM) and Bitumen, on the changes of soil aggregate properties and crop yields. The soil conditioners were treated at the rates of 0.5% and 1% to sandy loam and silty clay loam soils. The aggregate stability, wetting angle, mean weight diameter and air permeability were analyzed. Pot experiments were carried out to investigate the soybean growths and soil property changes after the soil conditioners were sprayed to surface soils. Soil aggregate stability was increased remarkably by the soil conditioner, PAM and Bitumen, treatments. PAM was more effective in sandy loam than silty clay loam, but Bitumen was better in silty clay loam. Wetting angle of the soil was changed slightly by PAM treatment, but it was greatly changed to hydrophobic by Bitumen treatment. Air permeability, water infiltration rate and moisture retention of the soils were increased by surface application of soil conditioners, PAM and Bitumen. The growths of soybean in conditioner applicated pots were better than those of untreated pots from early stage, and the yields were increased 6-13%.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.1
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• pp.58-64
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• 2009

The objectives of this study were to investigate the aggregate fragmentation in wet-sieving and to evaluate the relationship between the aggregate fragmentation fractal dimension and macro-porosity of upland soils, using three different textural types of soils including Gopyeng series (Fine, Typic Hapludalfs), Gyuam series (Fine silty over coarse silty, Fluvaquentic Eutrudepts), and Jungdong series (Coarse loamy, Typic Udifluvents) located in Gyeonggi province. Undisturbed soil samples with five replicates were seasonally sampled and used for measuring water stable aggregate, macropores, and physico-chemical properties of soils. The aggregate stability in wet-sieving was digitalized as three types of fragmentation fractal dimension ($D_f$), geometric mean diameter (GMD), and mean weight diameter (MWD). $D_f$ had higher correlation with GMD than with MWD. Seasonal aggregate stability showed the highest values in summer, and decreased in the order of spring and autumn. The macroporosity had higher in topsoil, in autumn, and in ridge, than in plow pan layer, in summer, and in row, respectively. The relationship between $D_f$ and macroporosity, especially more than 99 m, showed high correlation only in soils with $D_f$ less than 3.1, which means more aggregated soils compared to soils with $D_f$ more than 3.1. Besides, in the soils with the fractal dimension less than 3.1, the power function relation between saturated hydraulic conductivity and macroporosity more than 99 m had relatively high determinant coefficient, and vice versa. Therefore, it could be thought that fragmentation fractal dimension is available for confirming macroporosity induced from aggregation.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.719-733
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• 2016

This study was carried out to investigate the effect of no-tillage on sequential cropping supported from recycling of first crop ridge on the productivity of crop and physical properties of soil under green house condition. This study is a part of "No-tillage agriculture of Korea-type on recycled ridge". From results for distribution of soil particle size with time process after tillage, soil particles were composed with granular structure in both tillage and no-tillage. No-tillage soil in distribution of above 2 mm soil particle increased at top soil and subsoil compared with tillage soil. Tillage and one year of no-tillage soil were not a significant difference at above 0.25 mm~below 0.5 mm, above 0.5 mm~below 1.0 mm, and above 1.0 mm of water-stable aggregate. Two years of no-tillage soil was significantly increased by 8.2%, 4.5%, and 1.7% at above 0.25 mm~below 0.5 mm, above 0.5 mm~below 1.0 mm, and above 1.0 mm of water-stable aggregate, respectively, compared with one year of no-tillage. Bulk density of top soil was $1.10MG\;m^3$ at tillage and $1.30MG\;m^3$ at one year of no-tillage. Bulk density of top soil was $1.14MG\;m^3$ at two years and $1.03MG\;m^3$ at three years of no-tillage, respectively. Bulk density of subsoil was a similar tendency. Solid phase ratio in top soil and subsoil was increased at one year of no-tillage compared with tillage soil, while soil phase ratio decreased at two and three years of no-tillage. Pore space ratio in tillage top soil (58.5%) was decreased by 8.5% at compared with no-tillage soil (51.0%). Pore space ratio was 56.9% and 61.2% at two and three years of no-tillage soil, respectively. Subsoil was a similar tendency. Gaseous phase ratio was decreased at one year of no-tillage soil, and increased at two and three years of no-tillage soil compared with tillage soil. Liquid phase ratio in top soil was increased at one year of no-tillage (28.3%), and decreased at two years (23.4%) and at three years (18.3 %) of no-tillage soil compared with tillage soil (24.2%). Subsoil was a similar tendency. Liquid phase ratio in subsoil was increased than top soil.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.161-166
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• 2021

This study was on leaching test(KSLT) of the aggregate for the products to evaluate the characteristics of contaminants and the possibility of contamination arising from the aggregate. On the basis pH, conductivity, turbidity, TN, TP, COD and heavy metal contents in the aggregate increased as the particle size of the aggregate was smaller. The pH appeared to be 9.9~11.4 which is relatively higher than soil, however, heavy metal has investigated within the 1 region's standard value of soil pollution standards. From the leaching test, there is strong indication that the risk of pollution due to elution of pollutants gets higher with the smaller grain size. Especially conductivity and turbidity are the potential water pollution source and recycled aggregates of 10mm or less could be a potential pollution source since it could elute soluble matters and suspended solid, but there is no proper management standard for them. As a result of evaluating water pollution possibility of the aggregate, the pH displayed in items with a very high possibility of contamination, TN and TP did in item with a low possibility of contamination and on the other hand the heavy metals did in item with a very low possibility of contamination.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.479-488
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• 2005

Geopier soil reinforcement system which crushed aggregate is put into a hole and rammed the aggregate with tamper is a viable alternative to deep foundation to over-excavation and replacement. Also, Geopier is intermediate foundation of deep and shallow foundation. In this paper, the value of Geopier element stiffness modulus($K_g$) when designed is compared with the measured value($K_g$) by the in-situ modulus Load test in the field. Also, this paper presents a technology overview of system capabilities and application for foundation reinforcement of structures.

• KCI Concrete Journal
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• v.14 no.4
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• pp.161-169
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• 2002

The mechanical properties of fiber reinforced porous concrete for use as a planting material were investigated in this study. Changes in physical and mechanical properties, subsequent to the addition of carbon fiber and silica fume, were studied. The effects of recycled aggregate were also evaluated. The applicability as planting work concrete material was also assessed. The results showed that there were no remarkable changes in the void and strength characteristics following the increase in proportion of recycled aggregate. Also, the mixture with 10% silica fume was found to be the most effective for strength enforcement. The highest flexural strength was obtained when the carbon fiber was added with $3\%$. It was also noticed that PAN-derived carbon fiber was superior to Pitch-derived ones in view of strength. The evaluation of its usage for vegetation showed that the growth of plants was directly affected by the existence of covering soil, in case of having the similar size of aggregate and void.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.219-224
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• 2005

A aggregate size distribution is an important in successful crop production in reclaimed tidelands. The aggregate size distribution for this study were determined of 0.1mm, 0.5mm, 1.0mm, and 2.0mm by wet sieving method. Agricultural activity, period of reclamation showed significant effects on aggregate size distribution in reclaimed tidelands. The percentage of <2mm aggregates for SMG, GHD, and SM reclaimed tidelands were ranged 8.9, 36.7, and 38.0%, respectively. The percentage of >0.1mm aggregates for SMG, GHD, and SM reclaimed tidelands were ranged 9.0, 26.0, and 48.9%, respectively.