• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.107-108
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• 2015

Layered Double Hydroxides is known as a hydrotalcite-like material. It is a type of anionic clay with planar structure. It is composed of layer structure which is able to exchange anion between two layers which includes divalent ion and trivalent ion. Therefore, layered double hydroxide is applicable for eliminating harmful heavy metals and anionic substances which exist in the concrete. Because it is also able to be used as catalyst and has high possibility of utilization, It is getting an large amount of attention recently. In this study, an analysis on the structure of the layerd double hydroxide (LDH) which is possible to bind the anion was carried out.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.3
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• pp.19-26
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• 2011

In order to estimate the viscous effects of clay over a wide range of strain levels, we confirmed the performance of a viscoelastic-viscoplastic constitutive model by simulating cyclic undrained triaxial tests to determine the cyclic strength and deformation characteristics of natural marine clay. The viscoelastic-viscoplastic constitutive model was then incorporated into an effective stress-based seismic response analysis to estimate the effects of an intermediate clay layer on the behavior of sand layers. Seismic response was simulated by the cyclic viscoelastic-viscoplastic constitutive model created with data recorded at Rokko Island, Kobe, Japan. The results show that a cyclic viscoelastic-viscoplastic constitutive model can provide a good description of dynamic behavior including viscoelastic effects, within a small strain range.

• Macromolecular Research
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• v.15 no.1
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• pp.51-58
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• 2007

The approach studied in the present work produced an exfoliated state of clay layers via confinement of the charged nano-sized polystyrene (PS) beads within the gallery of swollen pristine clay. It was demonstrated that adsorption of the polymer nanobeads dramatically promotes expansion of the clay gallery. A comparative study of incorporation was conducted by employing organo-modified clay along with two different colloid polymer systems: electrostatically stabilized PS nanobeads and cationic monomer-grafted PS nanobeads. The mechanism of adsorption of the monomer-grafted polymer beads onto clay via cationic exchange between the alkyl ammonium group of the polymer nanobeads and the interlayer sodium cation of the layered silicate was verified by using several techniques. As distinct from the polymer nanobeads formed using conventional miniemulsion polymerization method, competitive adsorption of stabilizing surfactant molecules was be prevented by grafting the surface functional groups into the polymer chain, thereby supporting the observed effective adsorption of the polymer beads. The presence of surface functional groups that support the establishment of strong polymer-clay interactions was suggested to improve the compatibility of the clay with the polymer matrix and eventually play a crucial role in the performance of the final nanocomposites.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.417-424
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• 2005

Observed field behaviors are frequently different from the behaviors predicted in the design state due to several uncertainties involved in soil properties, numerical modelling, and error of measuring system even though a sophisticated numerical analysis technique is applied to solve the consolidation behavior of drainage-installed soft deposits. In this study, genetic algorithms are applied to back-analyze the soil properties using the observed behavior of soft clay deposit composed of multi layers that shows complex consolidation characteristics. Utilizing the program, one might be able to appropriately predict the subsequent consolidation behavior from the measured data in an early stage of consolidation of multi layered soft deposits. Example analyses for drainage-installed multi-layered soft deposits are performed to examine the applicability of proposed back-analysis method.

• Fibers and Polymers
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• v.5 no.2
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• pp.160-169
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• 2004

Polystyrene/layered silicate nanocomposites were prepared by melt intercalation. To examine the distribution of the clay in polymer matrix, small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) were used. Intercalated nanocomposites were obtained and their rheological properties were investigated. Microcellular nanocomposite foams were produced by using a supercritical fluid. As clay contents increased, the cell size decreased and the cell density increased. It was found that layered silicates could operate as heterogeneous nucleation sites. As the saturation pressure increased and the saturation temperature decreased, the cell size decreased and the cell density increased. Microcellular foams have different morphology depending upon the dispersion state of nanoclays.

• Journal of Industrial Technology
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• v.26 no.A
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• pp.101-108
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• 2006

This study is the results of experimental and numerical study on the consolidational behavior of multi-layered soft soil ground installed with plastic board drains (PBD). Centrifuge model tests with a marine clay sampled from field were performed to investigate the consolidational behavior of multi-layered ground where a dredged soil was placed on the soft clay ground and PBDs were installed. Test results were compared with those of numerical analyses, using the 2-D equivalent model previously proposed. From test results, it was found that the amount of consolidation settlement occurred in the original ground due to embankment surcharge loads was in the range of 38% of total settlement in the whole ground. From the results of cone penetration tests executed after finishing the centrifuge model tests, the cone resistance was found to increase with depth. The measured water contents inbetween PBDs were in the ranges of 38~50% and their values tended to increase with increasing the distance between PBDs.

• Bulletin of the Korean Chemical Society
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• v.18 no.5
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• pp.473-474
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• 1997

• Journal of the Korean Ceramic Society
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• v.41 no.1
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• pp.41-44
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• 2004

Hydrophilicity and hydrophobicity of pottery bodies can be controlled via chemical substitution of layered clay with hydrophilic and hydrophobic organics. In this study, organo-clay nanocomposites were prepared by ion-exchange of montmorillonite with dodecylamine and hexadecylamine, respectively. Substitution sites of organics and the interval changes of layered materials are characterized by FT-IR and WAXD and organics amounts loaded and water comtents contained by C/S analysis and TG-DSC. The organics were selectively intercalated so that increase layer interval from 12${\AA}\; to\;16{\AA}$. Organo-modified clay is changed to more hydrophobic comparing to clay itself.

• Membrane Journal
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• v.15 no.4
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• pp.255-271
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• 2005

polymer/layered silicate nanocomposite (PLSNs) is new type of materials, based on clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation. It could be prepared via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymerization and melt intercalation. The whole range of polymer is used, i.e. thermoplastics, thermosets and elastomers as a matrix. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfolicate nanocomposites where the separated, individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filer level, usually inferior to 5wt$\%$, such as increased mechanical properties, increase in thermal stability and gas barrier properties and good flame retardancy. Gas permeability through the PLSNs films decreased due to increased tortuosity made by intercalation or exfoliation of clay in polymer.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.329-332
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• 2002

In the present study, in order to apply a cyclic viscoelastic-viscoplastic constitutive model to multi-layered ground conditions during large earthquake, the numerical simulations of the 1995 Hyogoken Nanbu Earthquake at Port Island, Kobe, Japan, were performed by the seismic respons analysis. From the seismic response analysis, it was verified that a cyclic viscoelastic-viscoplastic constitutive model can give a good description of the damping characteristics of clay accurately during large event which induces plastic deformation in large strain range.