• Title/Summary/Keyword: SGR공법

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Strength Development Mechanism of Inorganic Injection Material (무기질계 주입재의 강도발현 메커니즘)

  • Han, yunsu;Lee, Jonghwi;Kang, Hyoungnam;Baeg, Seungin;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.10
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    • pp.5-12
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    • 2011
  • Recently, NDS(Natural and Durable Stabilizer)method and other similar methods are composed of inorganic accelerating agent and the ultra-super fine cement have been studied as the ground improvement material in Korea. However, in the existing research, the chemical changing process of NDS in the strength development mechanism with the elapsed curing time and the principles of strength development did not give an explanation. For the popularization of the inorganic grout material, it determined that the mechanism verifying of the curing process had to be clearly preceded. Therefore, unconfined compression test, SEM and XRD analysis were performed by the elapsed curing time and were analyzed. In addition, the same trial for SGR method, that is the representative example of the water glass grout material, was selected as comparative target in order to distinguish properties of NDS more clearly. The result of experiment, the strength development mechanism of NDS could be investigated through the close correlation of the unconfined compression strength - SEM - XRD analysis, and excellence of a performance was confirmed.

Application of Earth Natural Grouting Using Micro Cement and Inorganic material (마이크로시멘트 무기질계 그라우팅 ENG의 적용성 연구)

  • Jung, Min-Hyung;Kim, Yong-Sik;Jung, Chun-Hak;Lee, Song
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.1
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    • pp.109-116
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    • 2010
  • The Water glass grouting method has been applied frequently to penetration grouting in practice, but some problems, such as decrease of durability with the elapsed time and environmentally adverse effect, are raised recently. Hence, the Earth Natural Grouting method which uses micro cement and inorganic material is developed to overcomes those problems of the water glass grouting method, and is aimed for extensive ground injection bound. Volumetric strain test, syneresis test, unconfined compression test, triaxial permeability test, in-situ permeability test and heavy metal analysis were conducted to verify application of the ENG. As the result of tests, volumetric strain, syneresis and unconfined strength of the ENG were superior to those of the Water Glass SGR and ENG was proved to be impermeable. Also it is expected that the ENG would not have an effect on environmental pollution.

An Evaluation of Structural Performance of Reinforced Concrete Column Retrofitted with Grid Type Unit Details of Jacketing Method (격자형 유닛 상세를 가진 단면증설공법으로 보강된 철근콘크리트 기둥의 구조성능평가)

  • Moon, Hong Bi;Lee, Jeong In;Lee, Young Hak
    • Journal of Korean Association for Spatial Structures
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    • v.22 no.1
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    • pp.41-49
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    • 2022
  • In the case of columns in buildings with soft story, the concentration of stress due to the difference in stiffness can damage the columns. The irregularity of buildings including soft story requires retrofit because combined load of compression, bending, shear, and torsion acts on the structure. Concrete jacketing is advantageous in securing the strength and stiffness of existing members. However, the brittleness of concrete make it difficult to secure ductility to resist the large deformation, and the complicated construction process for integrity between the existing member and extended section reduces the constructability. In this study, two types of Steel Grid Reinforcement (SGR), which are Steel Wire Mesh (SWM) for integrity and Steel Fiber Non-Shrinkage Mortar (SFNM) for crack resistance are proposed. One reinforced concrete (RC) column with non-seismic details and two columns retrofitted with each different types of proposed method were manufactured. Seismic performance was analyzed for cyclic loading test in which a combined load of compression, bending, shear, and torsion was applied. As a result of the experiment, specimens retrofitted with proposed concrete jacketing method showed 862% of maximum load, 188% of maximum displacement and 1,324% of stiffness compared to non-retrofitted specimen.