• Title/Summary/Keyword: Embedded Concrete

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Self Diagnosis Monitoring System of Carbon and Glass Hybrid Fiber Materials for Concrete Structures (CFGFRP 복합재료를 이용한 콘크리트 자기진단 모니터링)

  • Park, Seok-Kyun;Kim, Dae-Hun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.359-362
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    • 2005
  • Self diagnosis monitoring system is defined as concrete structural carbon and glass hybrid fiber materials, in response to the change in external disturbance and environments, toward structural safety and serviceability as well as the extension of structural service life. In this study, carbon and glass hybrid fiber materials were investigated fundamentally for the applicability of self diagnosis in smart concrete structural system as embedded functions of sensors.

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3D FE Analysis of Cast-in-situ Concrete Pile embedded in Weathered Rock (풍화암에 지지된 현장타설말뚝의 3차원 해석)

  • Kim, Sang-Baek;Lee, Whaol;Kwon, Oh-Kyun;Choi, Yong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03b
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    • pp.167-172
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    • 2000
  • In this study, the behaviors of a cast-in-situ concrete pile embedded in the weathered rock were analysed by a 3D numerical analysis using PENTAGON 3D and the results were compared with those of the field load test. The load-settlement relation and the load transfer relationship were evaluated from the numerical analysis. As a result, the load-settlement relation at the pile top and the axial load distribution with depth were predicted reasonably. And those results were similar with those of the field load test.

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Monitoring of Retrofitted Reinforced Concrete Beams with Hybrid Fiber Reinforced Polymer (광섬유 센서를 이용한 복합 섬유 재료로 보강된 철근 콘크리트 보의 모니터링)

  • 이옥기;신영수;김기수;김종우
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.509-514
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    • 2001
  • The Fibre-optic Bragg grating (FBG) sensor is broadly accepted as a structural health monitoring device for Fibre reinforced plastic (FRP) materials by either embedding into or bonding onto the structures. The accuracy of the strain measured by using the FBG sensor is highly dependent on the bonding characteristics among the bare optical fibre, protective coating, adhesive layer and host material. In general, the signal extracted from the embedded FBG sensor should reflect the straining condition of the host structure. This paper presents a theoretical model to evaluate the differential strains between the bare fibre and host material with different adhesive thickness and modulus of the protective coating of the embedded FBG sensor.

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Dispertion Effect of Hydration Heat due to Materials and Standard Variation of Embedded Heat Pipe (매입형 히트파이프의 재질 및 규격변화에 따른 수화열 분산 효과)

  • Kim, Myung-Sik;Yeom, Chi-Sun;Baek, Dong-Il
    • Journal of Ocean Engineering and Technology
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    • v.23 no.6
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    • pp.111-116
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    • 2009
  • The cracking due to hydration heat in mass concrete must be resolved to improve the stability and durability of concrete structures. In this study, the economic efficiency was improved by replacing a copper pipe with a steel one for the heat pipe, and the heat pipe was standardized to significantly improve the operation efficiency, such as the processing, transport, assembly, and construction time. As a result of the experiment, the peak temperature of the ICSHP, ISSHP, and ISUHP specimens decreased by about $7.2{\sim}10.9^{\circ}C$ compared to the OPC specimen and the probability of a thermal crack being generated in the ICSHP, ISSHP, and ISUHP specimens decreased by up to 84~88%.

Pullout resistance of concrete anchor block embedded in cohesionless soil

  • Khan, Abdul J.;Mostofa, Golam;Jadid, Rowshon
    • Geomechanics and Engineering
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    • v.12 no.4
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    • pp.675-688
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    • 2017
  • The anchor block is a specially designed concrete member intended to withstand pullout or thrust forces from backfill material of an internally stabilized anchored earth retaining wall by passive resistance of soil in front of the block. This study presents small-scale laboratory experimental works to investigate the pullout capacity of a concrete anchor block embedded in air dry sand and located at different distances from yielding boundary wall. The experimental setup consists of a large tank made of fiberglass sheets and steel framing system. A series of tests was carried out in the tank to investigate the load-displacement behavior of anchor block. Experimental results are then compared with the theoretical approaches suggested by different researchers and codes. The appropriate placement of an anchor block and the passive resistance coefficient, which is multiplied by the passive resistance in front of the anchor block to obtain the pullout capacity of the anchor, were also studied.

Agglomeration effects on the buckling behaviour of embedded concrete columns reinforced with SiO2 nano-particles

  • Zamanian, Mohammad;Kolahchi, Reza;Bidgoli, Mahmood Rabani
    • Wind and Structures
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    • v.24 no.1
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    • pp.43-57
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    • 2017
  • The use of nanotechnology materials and applications in the construction industry should be considered for enhancing material properties. However, the nonlinear buckling of an embedded straight concrete columns reinforced with silicon dioxide ($SiO_2$) nanoparticles is investigated in the present study. The column is simulated mathematically with Euler-Bernoulli and Timoshenko beam models. Agglomeration effects and the characteristics of the equivalent composite are determined using Mori-Tanaka approach. The foundation around the column is simulated with spring and shear layer. The governing equations are derived using energy method and Hamilton's principal. Differential quadrature method (DQM) is used in order to obtain the buckling load of structure. The influences of volume percent of $SiO_2$ nanoparticles, geometrical parameters and agglomeration on the buckling of column are investigated. Numerical results indicate that considering agglomeration effects leads to decrease in buckling load of structure.

Effect of Fluorination on Pull-out Response of Carbon Fiber Embedded in Cement Matrices (플루오르화에 의해 표면개질된 탄소섬유의 시멘트 매트릭스 내 매입인발거동)

  • Jeon Esther;Han Byung-Chan;Yang Il-Seung;Park Wan-Shin;Lee Young-Seak;Yun Hyun-Do
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.45-48
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    • 2004
  • This paper aimed at the development of hydrophilic carbon fiber with improved tensile strength and ductility, numerous single fiber pullout tests from different cement matrices were performed. Fiber debonding and pullout have a large influence on the tensile stress - crack opening behavior of fiber concrete. Both debonding and pullout depend on the quality of the matrix, as well as on the embedded length of the carbon fiber. In this paper, all fiber pullout tests were carried out using high strength carbon fibers, both without fluorinationed and with fluorinationed carbon fiber.

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An Experimental Study on Measurement of Corrosion Initiation in Reinforced Concrete Exposed to Chloride Using EIS Method (EIS를 이용한 염해에 노출된 철근콘크리트의 부식개시 측정에 관한 실험적 연구)

  • Park, Dong-Jin;Park, Jang-Hyun;Lee, Kwang-Soo;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.11a
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    • pp.61-62
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    • 2017
  • In this study, the initiation of steel corrosion was monitored due to chloride attack using embedded sensor. In general, Steel bars embedded in concrete are protected from corrosion by being forming a passive film on the surface. However, the passive film is destroyed by chemical erosion such as concrete carbonation and chloride penetration, and the rebar is exposed to the deteriorating factor and corrosion proceeds. In order to realize the initiation of steel corrosion, OCP and change of Impedance parameter were observed by using Half-cell and EIS method depending on cover depth. As result, 10mm cover showed the impedence increased in 6weeks.

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Slip Failure Strength of Infilled Concrete with Reinforced PHC Pile by One-Cutting Method (원커팅 철근보강 PHC 말뚝의 속채움 콘크리트 부착파괴 성능)

  • Chun, Young-Soo;Sim, Young-Jong;Park, Jong-Bae
    • Land and Housing Review
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    • v.2 no.4
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    • pp.553-558
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    • 2011
  • Existing method protruding strands that are embedded in PHC pile to connect pile head and foundation slab shows poor constructibility. As this causes crack and damage in pile head and casualties often occurs in construction site during the work, alternative method called one-cutting method, in which pile above the ground surface and strands embedded in pile are completely cut and pile head is reinforced with rebar for connection with foundation slab, is currently adopted. However, the capacity of details for these methods are not mechanically proved. In this study, in order to suggest proper details of reinforcement for one-cutting method, failures due to lack of shear resistance between infilled concrete and PHC pile are analyzed through experiments and embedded depth with infilled concrete inside PHC pile is suggested. Assuming that slip failure strength is 0.4MPa, which is obtained from experiment conservatively, to have rebar yielded before slip failure, minimum depth of infilled concrete for PHC 450 and PHC 500, need to be 600mm above, and for PHC 600, 1,000mm above.

Shear behavior of non-persistent joints in concrete and gypsum specimens using combined experimental and numerical approaches

  • Haeri, Hadi;Sarfarazi, V.;Zhu, Zheming;Hokmabadi, N. Nohekhan;Moshrefifar, MR.;Hedayat, A.
    • Structural Engineering and Mechanics
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    • v.69 no.2
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    • pp.221-230
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    • 2019
  • In this paper, shear behavior of non-persistent joint surrounded in concrete and gypsum layers has been investigated using experimental test and numerical simulation. Two types of mixture were prepared for this study. The first type consists of water and gypsum that were mixed with a ratio of water/gypsum of 0.6. The second type of mixture, water, sand and cement were mixed with a ratio of 27%, 33% and 40% by weight. Shear behavior of a non-persistent joint embedded in these specimens is studied. Physical models consisting of two edge concrete layers with dimensions of 160 mm by 130 mm by 60 mm and one internal gypsum layer with the dimension of 16 mm by 13 mm by 6 mm were made. Two horizontal edge joints were embedded in concrete beams and one angled joint was created in gypsum layer. Several analyses with joints with angles of $0^{\circ}$, $30^{\circ}$, and $60^{\circ}$ degree were conducted. The central fault places in 3 different positions. Along the edge joints, 1.5 cm vertically far from the edge joint face and 3 cm vertically far from the edge joint face. All samples were tested in compression using a universal loading machine and the shear load was induced because of the specimen geometry. Concurrent with the experiments, the extended finite element method (XFEM) was employed to analyze the fracture processes occurring in a non-persistent joint embedded in concrete and gypsum layers using Abaqus, a finite element software platform. The failure pattern of non-persistent cracks (faults) was found to be affected mostly by the central crack and its configuration and the shear strength was found to be related to the failure pattern. Comparison between experimental and corresponding numerical results showed a great agreement. XFEM was found as a capable tool for investigating the fracturing mechanism of rock specimens with non-persistent joint.