• 제목/요약/키워드: Clay materials

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A Study on the Indexes and Properties of Mechanical Weathering to Granite Distributed in Korea (화강암의 풍화산물에 대한 기계적 풍화지수의 특성에 관한 연구)

  • Rheem, Chong-Ho
    • Journal of the Korean Geographical Society
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    • 제28권2호
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    • pp.99-111
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    • 1993
  • The transformation of rocks into unconsoli-dated debris is the prime geomorphic processes including weathering and soil forming process. In these processes, rocks tend to be unconsol-idated debris with small particles. Particularly, typical granite is more likely affected by weathering, since the rock consists of quartz, feldspar and mica that can be easily coarse-grained and well jointed without bedding. The purposes of this study are to clarify the index and properties of mechanical weathering that contributed to transformation of granite distributed in Korea. A total of seventy-three samples of weathering products of granite in Korea were collected during the three-year period, March 30, 1989 to February 21, 1992. The prticle analysis was performed for clay, silt and sand using Sieve and Hydrometer. The results of the analysis are as the followings: First, soil textures in the study area are included seven categories of textures as C, CL, SCL, Sil, SL, LS, and S. Among these textures, the most frequent soil texture were SL, S and SCL in order. Second, the weathering products of granite are crumbled by weathering and hydrothermal. Clay texture consisted of fine materials seems to be influenced by hydrothermal, while Sand texture composed of coarse materials, seems to be significantly influenced by weathering. Third, the index of mechanical weathering by region indicates that Hawngdeung(1) is the lowest as 2.37 and the index by soil texture shows that Clay texture is the lowest as 2.46. Forth, the regression analysis of MW showes that sand/clay variable is the most significant variable. Finally, pedochemical weathering is prevailed on the clayey gruss and geochemical weathering is on the gruss and shattering is on the weathered rock, strongly, but the fine materials in some sites were formed by argillation of hydrothermal.

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Influence of Playground Land Covers on the Human Thermal Sensation (운동장 포장재료가 인간 열환경에 미치는 영향)

  • Hyun, Cheolji;Jo, Sangman;Park, Sookuk
    • Journal of the Korean Institute of Landscape Architecture
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    • 제47권3호
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    • pp.12-21
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    • 2019
  • In order to investigate the effect of various pavement materials (artificial grass, natural grass, and clay sand) on the human thermal environment, the microclimate data in early autumn (air temperature, humidity, wind speed, and shortwave and longwave radiation) were measured and compared on each surface. The mean air temperature, humidity and wind speed of the pavement materials did not differ significantly and showed the greatest difference in the mean radiant temperature. Natural grass, which has the highest albedo, has the highest amount of shortwave radiation. The artificial turf had the highest surface temperature and the highest amount of longwave radiation. In the human thermal environment index PET, artificial grass > clay sand > natural grass. Natural grass had a maximum 2/3 level lower and a mean 1/2 level lower in PET as compared to artificial grass. The clay sand pavement had a maximum 2/3 level lower and a mean 1/3 level lower than the artificial grass. Natural grass had a maximum 1/3 level lower than the clay sand pavement. Their UTCIs showed smaller differences than the PETs. Therefore, it is necessary to carefully choose materials from the planning stage when designing outdoor spaces, including playgrounds.

Performance evaluation of β-glucan treated lean clay and efficacy of its choice as a sustainable alternative for ground improvement

  • Kumara, S. Anandha;Sujatha, Evangelin Ramani
    • Geomechanics and Engineering
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    • 제21권5호
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    • pp.413-422
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    • 2020
  • The choice of eco-friendly materials for ground improvement is a necessary way forward for sustainable development. Adapting naturally available biopolymers will render the process of soil stabilization carbon neutral. An attempt has been made to use β-glucan, a natural biopolymer for the stabilization of lean clay as a sustainable alternative with specific emphasis on comprehending the effect of confining stresses on lean clay through triaxial compression tests. A sequence of laboratory experiments was performed to examine the various physical and mechanical characteristics of β-glucan treated soil (BGTS). Micro-analysis through micrographs were used to understand the strengthening mechanism. Results of the study show that the deviatoric stress of 2% BGTS is 12 times higher than untreated soil (UTS). The micrographs from Scanning Electron Microscopy (SEM) and the results of the Nitrogen-based Brunauer Emmett Teller (N2-BET) analysis confirm the formation of new cementitious fibres and hydrogels within the soil matrix that tends to weld soil particles and reduce the pore spaces leading to an increase in strength. Hydraulic conductivity (HC) and compressibility reduced significantly with the biopolymer content and curing period. Results emphases that β-glucan is an efficient and sustainable alternative to the traditional stabilizers like cement, lime or bitumen.

Strength Characteristics of Anlsotropic Overconsalidated Clay (이방성과압밀점토의 강도특성)

  • 홍원표
    • Geotechnical Engineering
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    • 제4권3호
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    • pp.35-42
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    • 1988
  • A series of consolidated-undrained cubical triaxial tests was performed to investigate the three- dimensional strength characteristics of anisotropic overconsolidated clay. All specimens sampled in field were loaded under conditions of principal stress directions fixed and aligned with the directions during sampling. A sufficient number of tests It was performed to deter.mine the three- dimensional failure surface in the octahedral plane. The adjusted effective friction angles obtained by the stress state projected on the same octahedral plane did not show anisotropy, while the measured effective friction angles showed considerally difference according to the axes of speccimens. Therefore, Lade failure criterion proposed fort isotropic materials could be also used practically for anisotropic overconsolidated clay. The direction of the plastic strain increment wrectors superimposed on the principal stress space was nearly perpendicular to the traces of the failure surface in the octahedral plane.

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Characteristics of Specimens Made from Primary Clay and Red Hwangto with MSWI Fly Ash by Sintering Process (Sintering process에 의한 MSWI fly ash를 혼합한 일차점토(一次粘土)와 적황토(赤黃土) 공시체(公試體)의 특성(特性))

  • Yoo, Seung-Chol;Kwon, Moon-Sun;Park, Sang-Min
    • Resources Recycling
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    • 제19권2호
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    • pp.10-18
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    • 2010
  • This research investigates the feasibility of ceramic specimens made from Primary clay and Red Hwangto with MSWI fly ash. Specimens preduced by mix-design maximum 20 wt% MSWI fly ash were analysed by SEM, UTM, ICP, etc. As a result of measurement,$P_{10}$ specimen was improved on bending strength and $R_5$ specimen was improved on compressive and bending strength. Also amount of extracted heavy metal was suitable for regulatory limits. This indicates that MSWI fly ash is indeed suitable for the partial replacement of ceramic materials in bricks.

A Comparative Study on the Effect of Promoting Consolidation between SCP and GCP (SCP와 GCP의 압밀촉진효과에 관한 비교 고찰)

  • You, Seung-Kyong
    • Journal of the Korean Geosynthetics Society
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    • 제8권2호
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    • pp.41-46
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    • 2009
  • In this paper, a series of model tests were performed in laboratory to evaluate promoting consolidation of compaction pile methods for soft ground improvement. For the model tests, composite soil samples that have 10% replacement area ratio were prepared by using sand, gravel, and sandy gravel for the materials of compaction piles. After loading to each composite soil sample, the excess pore pressure dissipation and settlement were investigated. In addition, the behavior of clay mixed with each compaction pile was also monitored at the end of consolidation to evaluate clogging phenomenon. As a test result, the effects for decreasing settlement and promoting consolidation by GCP were prominent, and the mixed clay was not monitored in all of the three compaction piles.

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Case Study on Failure of Rock Slope Caused by Filling Material of Clay (점토 충전물에 의한 암반사면 파괴사례 연구)

  • Kim, Yong-Jun;Lee, Young-Huy;Kim, Sun-Ki;Kim, Ju-Hwa
    • Tunnel and Underground Space
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    • 제16권5호
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    • pp.368-376
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    • 2006
  • After heavy rainfall, It was occurred massive plane failure along bedding plane of shale in the center of rock slope. It was observed filling material and trace of underground water leakage around of the slope. We tried to find the cause for slope failure, and the result of examination showed that primary factors of the failure were low shear strength of clay filling material and water pressure formed within tension crack existed in the top of the slope. In this research, in order to examine the features of shear strength of filled rock joint, shear test of filled rock joint was conducted using of artificial filling material such as sand and clay..Also we made an investigation into the characteristics of shear strength with different thickness of filling materials.

The effect of seasonal water temperature on sedimentation characteristics of dredged clay (계절별 수온에 따른 점토의 침강압밀 특성 연구)

  • Oak, Young-Suk;An, Yong-Hoon;Lee, Chul-Ho;Choi, Hang-Seok
    • Proceedings of the Korean Geotechical Society Conference
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    • 한국지반공학회 2009년도 춘계 학술발표회
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    • pp.1183-1189
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    • 2009
  • The sedimentation rate of particles in a suspension is a function of particle size, initial slurry water content and salinity. Many researches conducted on the behavior of dredged soils have centered on such factors. However, there have been few attempts to assess another important influence factor of seasonal water temperature on designing the placement of dredged materials. In this paper, the effect of seasonal water temperature on sedimentation characteristics of dredged clay was investigated with consideration of three different water temperatures, that are $5^{\circ}C$, $15^{\circ}C$, $35^{\circ}C$, which represent critical water temperatures in winter, spring or fall, and summer, respectively. A series of experimental results reveal that the sedimentation rates for the water temperature of $15^{\circ}C$ and $35^{\circ}C$ are very similar each other, but that of $5^{\circ}C$ that represents a winter season leads to a considerably delayed sedimentation compared to the others. This may be attributable to the retardation of ion-leaching from clay particles at low water temperature.

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A Study on Mechanical Properties Improvement of Halogen-free Flame Retardant Compounds by Nanoclay Addition (나노클레이 첨가에 따른 할로겐프리 난연컴파운드의 기계적 특성에 관한 연구)

  • Hwang, Chan-Yun;Yang, Jong-Seok;Sung, Baek-Yong;Kim, Ji-Yeon;Park, Dae-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제28권2호
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    • pp.126-130
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    • 2015
  • In this study, some materials are organized and experimented with variables to obtain the optimum mix proportion for the mechanical property of halogen free flame resistance compound with varying addition of nano clay. Tensile strength, density and stiffness are tested in the room temperature. In this study, unlike existing layered structure, nano clay with tabular structure is used and sufficient stiffness, strength, thermal stability and gas block capability can be achieved with small amount of addition. Tensile strength and elongation test show high rupture strength only in specimens with compatibilizing agents while density test shows average measurement in all the specimens except T-9. It was confirmed that the measurement value according to the additives in compatibilizing agent or in nano clay of hardness test represents similarly.

Distribution Characteristics of Organic Matter and Heavy Metal of Sediment in Daecheon Port (대천항 퇴적물의 유기물 및 중금속 분포 특성)

  • Shin, Woo-Seok;Lim, Ji-Yoon;Yoon, Young-Gwan
    • Journal of Korean Society of Water Science and Technology
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    • 제26권6호
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    • pp.43-51
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    • 2018
  • In order to systematically and scientifically manage the organic and heavy metals against sediment at Daecheon Port, this study conducted particle composition, organic materials and heavy metals irradiation studies of sediments. Analysis of the grain size composition of sediments in the target study area showed the distribution characteristics of the mix of sand, silt and clay. That is, Station C (Stn. C) showed superior by fine-grained sediment, Station A and B (Stn. A and B) showed superior by coarse-grained sediment. The organic matter(COD, TOC, and IL) of Stn. C was appeared to be heavily polluted more than Stn. A and B. These data for the spatial properties in sediment showed that organic matter was related positively to the sediment silt-clay content. Also, in the case of heavy metals contamination in surface sediments, Stn. C was higher than Stn. A and B. Particularly, at the Stn. C, high organic matter concentration and C/N ratio value( >10) indicated that the sediment was composed highly of land-derived organic matter. From these results, it considered that the correlation analysis among to silt-clay, organic matter and heavy metal was found to have a good interrelationship.