• Title/Summary/Keyword: gravel

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The Properties of Pusan Clay : Magnetic Susceptibility of Deltaic sediments in Gadeok-do Area (부산점토의 특성: 가덕도 지역 조간대 퇴적물의 대자율)

  • 김성욱;김인수;이선갑;김무겸;정성교
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.747-752
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    • 2003
  • This study was carried out to understand the stratigraphy and depositional environment of clayey soils that distributed in the Gadeok-do area, Kimhae plain (Nakdong estuary). For the study, SPT core sampling and magnetic susceptibility analysis were conducted. Soils in study area is classified into five sedimentary facies ascending order; sand/gravel. clay, sand/gravel, clay, interbedded sand and silty clay. Analysis of magnetic susceptibility for Gadeok-do clayey soil reveals that depositional process and environment can be divided into upper, middle and lower layer, and they are closely related to the sea level change since late Quaternary.

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Preliminary Experiment of Gravel Contact Oxidation Process in the Tropics

  • Abdullah Keizrul bin;Omachi Toshikatsu
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.12-17
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    • 2006
  • Natural rivers have water purification functions called Gravel Contact Oxidation Process, which decontaminate river water by biological absorption, oxidation and degradation on riverbed gravels. This function has been developed and applied to many small/medium-sized urban rivers in Japan as one of the direct river water purification methods. However the method hasn't been verified in the tropics, which have different climate conditions and river characteristics. A preliminary experiment carried out at a polluted urban tributary in the outskirts of Kuala Lumpur, Malaysia where an increasing attention has been paid to river environment, showed a good applicability to the tropical conditions as a technically practical water purification measure with some maintenance cares for sludge management.

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Effect of Mix Proportion on the Flowing Characteristics of Super-flowing Concrete (초유동 콘크리트의 유동 성능에 미치는 배합요인의 영향)

  • 노재호;한정호;백명종;이보근;박기청
    • Proceedings of the Korea Concrete Institute Conference
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    • 1994.10a
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    • pp.115-120
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    • 1994
  • Recently super-flowing concrete has been developed and used in many construction sites in Japan. It is believed that super-flowing concrete will change the construction method and contribute to the durability of concrete structures. In this study the effect of mix proportion on the flowing characteristics of super-flowing concrete was investigated to establish the mix design method. From the result we have found that self-compactability of super-flowing concrete was greatly affected by the unit gravel volume and paste/gravel volume ratio. Therefore the two parameters can be used in mix design of super flowing concrete.

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A Study on the Stress Distribution in Soil According to the Composition of the Soil Layer in Case of Surface Loading (지표면 재하시 토층구성에 따른 지중응력분포에 관한 연구)

  • Lim, Jong-Seok;Jung, Sang-Kyun;Ha, Hyuk
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.510-516
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    • 2005
  • This research aims to verify the stress distribution in soil according to the composition of the soil layer in case of surface loading. For this purpose, loading tests with measurement of stresses in the soil on four kinds of layered model ground in laboratory were performed. Those are (1)homogeneous sand, (2)gravel underlain by sand, (3)sand underlain by clay and (4)gravel underlain by clay. Test results are compared and analysed for the compositions of the soil layers. based on the results obtained, it is found that the larger the difference of the strengths of upper and lower layer is, the smaller the stress in the soil in case of surface loading is.

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Development of Depot Encircled with Oxidation Canal for Water Quality Improvement (수질 개선을 위한 침전산화수로 개발)

  • 김원장;박상현
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42 no.6
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    • pp.83-89
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    • 2000
  • A depot encircled with contact oxidation canal has been developed to improve water qualityr. The depot is aimed to settle suspended solid in the flow. The oxidation canal is to contact the pollutants and oxygen in the surface of gravel filter to purify the water. The deposit of the pollutant in the depot is released by the drainage culvert located at the bottom of it. Aeration nozzle is installed to supply enough oxygen to the gravel filter layers in the bottom of the detent the flow and improve oxidation efficiency. From the experiment it is founded that 91% of SS, 39% of TN, 63% of TP and 77% of COD were removed in the system. The treatment efficiency of total nitrogen is rather lower than any other components, however, it would be higher when some floating vegetation is added in the primary clarifier. The depot and oxidation canal system would be useful to purify the flows in the mouth of the reservoirs or at the outlet of the drainage canal.

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Characteristic of Resilient Modulus and Unconfined Compressive Strength for Recycled Materials blend with Cement Kiln Dust (CKD 혼합에 따른 Recycled Material의 회복탄성계수와 일축압축강도 특성)

  • Son, Young-Hwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.2
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    • pp.19-25
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    • 2010
  • This study was conducted to determine the resilient modulus (Mr) and the unconfined compressive strength (UCS) of two recycled roadway materials such as recycled pavement material (RPM) and road surface gravel (RSG) with or without cement kiln dust (CKD). The recycled materials were blended with two CKD contents (5, 10 %) and 28 day curing time. Mr and UCS tests were also conducted after 10cycles of freezing and thawing to asses the impact of freeze-thaw cycling. Mr was determined conducting by the laboratory test method described by NCHRP 1-28A. Stabilized RPM and RSG had a modulus and a strength higher than unstabilized RPM and RSG. Mr and UCS of RPM and RSG mixed with CKD increased with increasing CKD content. The results indicated that the addition of CKD could be improved the strength and the stiffness of RPM and RSG. Therefore, RPM, RSG and CKD could be used as an effective materials in the reconstruction of roads.