• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.7-12
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• 2002

The purpose of this study is to design and to apply the self-compaction concrete mixture to field, having not only high strength but also compensation for shrinkage without thermal crack under 4 sides outer restraint of the member. In the experimental mix, replacement ratio of limestone Powder, CSA expansive additives, and unit water were selected as parameters, using portland blast-furnace slag cement. And, bleeding test, expansibility test, hydration heat analysis were performed. As a results, when Cement is replaced with 35% limestone Powder, 6% CSA expansive additives at unit water 175kg/$m^3$, demanded performances of fresh and hardened self-compaction concrete are accomplished in the field application.

• Journal of the Korea Institute of Building Construction
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• v.3 no.4
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• pp.135-138
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• 2003

The purpose of this study was to design the self-compaction concrete mixture, having not only high strength but also compensation of shrinkage without thermal crack under 4 sides outer restraint of the member. In the experimental mix, replacement ratio of limestone Powder, CSA expansive additives, and unit water were selected as parameters, using portland blast-furnace slag cement. And, bleeding test, expansibility test, hydration heat analysis were performed. As a results, when 35% of limestone Powder, 6% CSA expansive additives are replaced at unit water 175kg/$\textrm{m}^3$, demanded performances of fresh and hardened self-compaction concrete are accomplished.

• Journal of the Korea Institute of Building Construction
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• v.4 no.1
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• pp.85-88
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• 2004

The purpose of this study was to design the self-compaction concrete mixture, having not only high strength but also compensation of shrinkage without thermal crack under 4 sides outer restraint of the member. In the experimental mix, replacement ratio of limestone Powder, CSA expansive additives, and unit water were selected as parameters, using portland blast-furnace slag cement. And, bleeding test, expansibility test. hydration heat analysis were performed. As a results, when 35% of limestone Powder, 6% CSA expansive additives are replaced at unit water 175kg/$\textrm{m}^3$, demanded performances of fresh and hardened self-compaction concrete are accomplished.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.235-242
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• 2019

The objective of this study is to modify the mixture proportions of concrete that were developed for section enlargement strengthening elements using a specially designed binder composed of 5% ultra-rapid hardening cement, 10% polymer, and 85% ordinary portland cement in order to assign the self-compaction property to such concrete. The self-compaction abilities of concrete were estimated by the performance criteria specified in JSCE and EFNARC provions. Test results showed that the increase in the unit binder content at the consistent water-to-bider ratio led to increase in viscosity of fresh concrete but did not exhibit the decrease in the fluidity due to a greater viscosity. The mixture proportioning of self-compaction section enlargement concrete could be considered at the following conditions: unit binder contents of $430kg/m^3{\sim}470kg/m^3$ and fine aggregate-to-total aggregate ratios of 40%~46% at the water-to-binder ratio of 38%.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.397-403
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• 2009

This study was carried out to investigate the present status of subsoil compaction, and subsoil compaction management in orchard as a basic study for developing a self-propelled explosive subsoiler. Subsoil compaction was evaluated using the soil penetration resistance. Soil cone index was measured using the DIK 5520 type cone penetrometer in several fruit farms such as apple, pear, peach and grapes during growing seasons of these fruit in Jecheon, Gamgok, Choongju, Cheonan and Hwasung areas. Most of the subsoil managing machinery were either explosive type or digging type attached to the tractor or power tiller and turning radius of this machine was more than 3-5 m. Many of the farmers wanted to use the subsoiler which can put lime into soil and rupture soil at the same time. For most of the orchard fields, soil penetration resistance in vehicle traffic area was increased quickly and reached about 1.0 MPa in 5 cm soil depth. As the soil depth increased to 15-20 cm, cone penetration resistance reached about 2.0-2.5 MPa which restricted root growth seriously. Thus it was concluded that one of the main reason for increasing the soil compaction in orchard fields is agricultural vehicle traffic. In the vicinity of fruit trees, compaction is not so serious compared to that of the vehicle traffic area, but as the soil depth increased to 20-25 cm, in most of the orchard fields soil penetration resistance reached about 2.0-2.5 MPa which is the root growth-limiting value. Considering the rooting depth of fruit trees which ranged 30-60 cm for apple, pear and peach, and 20-30 cm for grape, it is necessary to loosen the subosoil and improve the subsoil conditions using subsoiler.

• Journal of the Korea Institute of Building Construction
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• v.3 no.3
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• pp.91-97
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• 2003

At present, the antiwashout underwater concretes are used as popular construction materials in European countries, the United States and Japan. The water-soluble polymers in the antiwashout underwater concretes provide excellent segregation or washout resistance, self-compaction and self-leveling property to the concretes. The purpose of this study is to recommend to optimum mix proportions of antiwashout underwater concretes according to compressive strength of 300kgf/$\textrm{cm}^2$ to 500kgf/$\textrm{cm}^2$. The antiwashout underwater concretes are prepared with various unit cement content, unit water content, sand-aggregate ratio, unit antiwashout agent and superplasticizer content. And they are tested for flowability, and compressive strength. From the test results, it is possible to recommend the optimum mix proportions of antiwashout underwater concretes according to compressive strengths within the range of 300kgf/$\textrm{cm}^2$ to 500kgf/$\textrm{cm}^2$.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.11-18
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• 2009

When underground pipe is installed, backfill materials need proper compaction. But in case of circular underground pipe, compaction of backfill material is difficult and compaction efficiency is poor at beloe the pipe. It caused the stability of underground pipe is reduced and various damages occurred. One of the solutions to solve this problem for underground pipe is to use controlled low strength material (CLSM). CLSM is made by concept of low strength concrete, which is applied to geotechnical engineering field. The representative characteristics of CLSM are self-leveling, self-compacting and flowability. In addition, its strength can be controlled and its construction method is simple. The behavior of underground pipe was investigated by finite element analysis for various backfill materials under same condition. As a result, in case of using the CLSM as backfill material, surface settlement and displacement of pipe are reduced comparing with those in case of using field soil or sand.

• The Journal of Advanced Prosthodontics
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• v.3 no.1
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• pp.10-15
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• 2011

PURPOSE. This study investigated the influence of bone quality and surgical technique on the implant stability quotient (ISQ) value. In addition, the influence of interfacial bone quality, directly surrounding the implant fixture, on the resonance frequency of the structure was also evaluated by the finite element analysis. MATERIALS AND METHODS. Two different types of bone (type 1 and type 2) were extracted and trimmed from pig rib bone. In each type of bone, the same implants were installed in three different ways: (1) Compaction, (2) Self-tapping, and (3) Tapping. The ISQ value was measured and analyzed to evaluate the influence of bone quality and surgical technique on the implant primary stability. For finite element analysis, a three dimensional implant fixture-bone structure was designed and the fundamental resonance frequency of the structure was measured with three different density of interfacial bone surrounding the implant fixture. RESULTS. In each group, the ISQ values were higher in type 1 bone than those in type 2 bone. Among three different insertion methods, the Tapping group showed the lowest ISQ value in both type 1 and type 2 bones. In both bone types, the Compaction groups showed slightly higher mean ISQ values than the Self-tapping groups, but the differences were not statistically significant. Increased interfacial bone density raised the resonance frequency value in the finite element analysis. CONCLUSION. Both bone quality and surgical technique have influence on the implant primary stability, and resonance frequency has a positive relation with the density of implant fixture-surrounding bone.

• Journal of Microbiology
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• v.40 no.4
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• pp.319-326
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• 2002

Cellular DNA in prokaryotes is organized in nucleic acid-protein self-assemblies referred to as the nucleoid. The physical forces responsible for its stability inside the poor solvent properties of the cytoplasm and their functional implications are not understood. Studies on the organisation and functioning of the cytosol of cells largely rely on experimental protocols performed in highly dilute solutions using biochemically purified molecules, which is not a reliable substitute for the situation existing in vivo. Our current research interest is focused on the characterization of biological and physical forces determining the compaction and phase separation of DNA in Escherichia coli cytoplasm. We have emphasized the effect of excluded volume in solutions with high macromolecular concentrations (macromolecular crowding) upon self-association patterns of reactions. The prokaryotic cytosol was simulated by addition of inert polymer polyethylene glycol (PEG) (average molecular weight 20000), as an agent which afterwards facilitates the self-association of macromolecules. Fluorescence microscopy was used for direct visualization of nucleoids in intact cells, after staining with DAPI (4',6-diamidino-2-phenylindole dihydrochloride). Addition of the crowding agent PEG 20,000, in increasing concentrations generated progressively enhanced nucleoid compaction, the effect being stronger in the presence of 0.2 M NaCl and 5 mM MgCl$\_$2/. Under these conditions, the nucleoids were compacted to volumes of around 2 ㎛$\^$3/ or comparable sizes with that of living cells.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.65-73
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• 2013

PURPOSES : As a research to develop a cement treated base course for an airport pavement which can enhance its drainage, this paper investigated the strength, infiltration performance and durability of the pervious concrete with respect to maximum coarse aggregate sizes and compaction methods. METHODS : This study measured compressive strength, infiltration rate, continuous porosity and freeze-thaw resistance of pervious concrete specimens, which were fabricated with five different compaction methods and different maximum aggregate sizes. In addition, in order to reduce the usage of Portland cement content and to enhance environment-friendliness, a portion of the cement was replaced with Ground Granulated Blast Furnace Slag (GGBS). RESULTS: Compressive strength requirement, 5 MPa at 7 days, was met for all applied compaction methods and aggregate sizes, except for the case of self-compaction. Infiltration rate became increased as the size of aggregate increased. The measured continuous porosities varied with the different compaction methods but the variation was not significant. When GGBS was incorporated, the strength requirement was successfully satisfied and the resistance to freezing-thawing was also superior to the required limit. CONCLUSIONS: The infiltration rate increased as the maximum size of aggregate increased but considering construct ability and supply of course aggregate, its size is recommended to be 25mm. With the suggested mix proportions, the developed pervious concrete is expected to successfully meet requirements for strength, drainage and durability for cement treated base or subbase course of an airport pavement.