• Title/Summary/Keyword: reinforcement materials

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A Study on Shear Resisting Effect of Reinforced Concrete Beams Filling-up Carbon Fiber Rod Plastic (전단보강근이 배근된 철근콘크리트 보의 CFRP전단보강효과에 관한 실험적 연구)

  • Kim, Woo-Hyoun;Lee, Hyoung-Seok;Kim, Young-Sik;Park, Sung-Moo
    • Proceeding of KASS Symposium
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    • 2005.05a
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    • pp.175-182
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    • 2005
  • The purpose of this study is to investigate experimentally the shear resisting behavior of the reinforced concrete beams strengthened with reinforcement materials(CFRP). Ten specimens were manufactured and tested under static monotonic loading. The main variables in the test were a space of steel reinforcement and direction of CFRP reinforcement. The test result Indicated that the method of CFRP increase significantly the shear strength of a reinforced concrete beam

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Trenchless Repairing-Reinforcing Process of Underground Pipes with Advanced Composite Materials (신소재 복합재료를 이용한 비굴착 지하매설관 보수-보강공법)

  • 진우석;권재욱;이대길;유애권
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.43-48
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    • 2001
  • To overcome the disadvantages of conventional excavation technology, various trenchless (or excavation free, or no-dig) repair-reinforcement technologies have been developed and tried. But trenchless technologies so fat developed have some brawbacks such as high cost and inconvenience of operation. In this study, a repairing-reinforcing process for underground pipes with glass fiber fabric polymer composites using VARTM(Vacuum Assisted Resin Transfer Molding) has been developed. The developed process requires shorter operation time and lower cost with smaller and simpler operating equipments than those of the conventional trenchless technologies. For the reliable operation of the developed method, a simple method to apply pressure and vacuum to the reinforcement was devised and flexible mold technology was tried. Also, resin filling and cure status during RTM process were monitored with a commercial dielectrometry cure monitoring system, LACOMCURE. From the investigation, it has been found that the developed repairing-reinforcing technology with appropriate process variables and on-line cure monitoring has many advantages over conventional methods.

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Reinforcement of underground cavities by Hi-FA(High performance and Multi functional Agent) (Hi-FA(유동성 및 점성 개질제)를 이용한 지하공동 보강사례)

  • Lim, Hai-Sik;Park, Yeung-Ho;Paik, Kyu-Ho;Lee, Yong-Jun;Park, Su-Yong
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.676-686
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    • 2010
  • Damage Cases of variously type are reported that the ground subsidence is caused by the underground cavities at structure and construction works in lime stone or abandoned zone. A underground cavities by direct for zone having an effect on structure have been filled with cement agents. But this measure is urgently needed in materials and work methods, because ground water pollution at water down fillings and flow out, ground disturb at high participle, damage of farms and fishery. The research confirm application of filling method and filling materials of environmentally friendly and economical by Hi-FA new materials have both liquidity and viscosity from case reinforcement in APT site, Gunsan.

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The Effect of the Reinforced Particles on the Mechanical and Fracture Behaviors of the SiC/Al2O3/Vinyl-Ester Composites (SiC/Al2O3/Vinyl-Ester 복합재료의 강화재 입자가 기계적 특성 및 파괴거동에 미치는 영향)

  • Kim, Da Jin Sol;Yun, Yu Seong;Kwon, Oh Heon
    • Journal of the Korean Society of Safety
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    • v.32 no.3
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    • pp.1-7
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    • 2017
  • Particle reinforced composites are materials that have enhanced physical properties by adding particle reinforcements to polymer materials and have been applied to a wide range of fields such as the aerospace, bio-technology and automative industry. In this study, particle reinforced composites were prepared by mixing $SiC/Al_2O_3$ to the vinyl ester as the thermoset resin. The purpose of this study is to evaluate mechanical properties and fracture behavior by the tensile test and single edge notch specimen according to the addition ratio of reinforcement. Addition of 1 and 2 wt% of the particle reinforcement to the vinyl-ester resin was effective for the strength improvement. However, when it was more than 3 wt%, its strength was decreased. Also the highest elastic modulus obtained as 3.19 GPa was found at the 2 wt% addition of reinforcement. Futhermore the fracture toughness was evaluated by the energy release rate and the maximum critical energy release rate was obtained when 1 wt% reinforcement. The results show that the limit of adding of $SiC/Al_2O_3$ for improvement of the mechanical and fracture performance is 2 wt% reinforcement particles.

An Experimental Study on the Strengthening Effect of RC Beams Strengthened by CFRP (탄소섬유 보강재로 보강한 RC 보의 보강효과에 관한 실험적 연구)

  • Kim, Jae-Hun;Park, Sung-Moo;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.5 no.4 s.18
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    • pp.71-77
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    • 2005
  • Bonded CFRP Plate method used murk in reinforcement method is very efficient for stress increment of reinforced members. But CFRP plate dosen't display enough its capacity and have the destruction characteristic of premature failure that reach failure by debond plate, because near-surface-bond using epoxy. Such destruction character of reinforced specimens take the influence at variables as steel reinforcement ratio, concrete strength, kind of reinforcement materials, reinforced length, property of epoxy used in binder and so on. In this study, performed experiment results are compared and considered on flexural performance of Near Surface Mounted Reinforcement used CFRP-Rod, as complement about structural behavior of RC beam reinforced flexural capacity in CFRP plate and premature failure of reinforcement material. Main variables of RC beam applied CFRP Plate external bond method are experimental variables as reinforcement length, reinforcement position (tension face and side face of beam) and existence of ironware in end parts. In case of CFRP-Rod, variable is reinforcement length.

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The Evaluation of Pullout Resistance and Installation Damage according to the Shape of Flexible Strip Reinforcement (신장형 띠형 보강재의 형상에 따른 인발저항 및 시공성능 평가 실험 연구)

  • Jeoung, Jaehyeung;Kim, Jaehong
    • The Journal of Engineering Geology
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    • v.31 no.3
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    • pp.321-332
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    • 2021
  • Though development of reinforced earth wall is on the rise recently, safety verification for various methods remains behind which has caused the problems including collapse after installation. This study aims to evaluate the field applicability of the shape of flexible strip reinforcement according to pullout resistance test and field damage test. The test specimens were 3 shape of reinforcement, the typical flexible band reinforcement, developed luged band reinforcement, and band type reinforcement made by cutting geogrid. It was found that reinforcement of type have strengths and weaknesses, respectively. The best type of flexible strip reinforcements can be selected, if the conditions are considered with the installation conditions of the reinforcing earth retaining wall and the particle size of the backfill materials.

Characteristic Behavior of High-Strength Concrete Columns under Simulated Seismic Loading

  • Hwang, Sun-Kyoung
    • International Journal of Concrete Structures and Materials
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    • v.18 no.2E
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    • pp.79-87
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    • 2006
  • The main objective of this research is to examine the behavior of high-strength concrete(HSC) columns. Eight test columns in one-third scale were tested under the conditions of cyclic lateral force and a constant axial load equal to 30% of the column axial load capacity. The $200{\times}200mm$ square columns were reinforced with eight DB bars constituting a longitudinal steel ratio of 2.54% of the column cross-sectional area. The main experimental parameters were volumetric ratio of transverse reinforcement(${\rho}_s$=1.58, 2.25 percent), tie configuration(Type H, Type C, Type D) and tie yield strength($f_{yh}$=548.8 and 779.1 MPa). It was found that the hysteretic behaviour and ultimate deformability of HSC columns were influenced by the amount and details of transverse reinforcement in the potential plastic hinge regions. Columns of transverse reinforcement in the amount 42 percent higher than that required by seismic provisions of ACI 318-02 showed ductile behavior. At 30% of the axial load capacity, it is recommended that the yield strength of transverse reinforcement be held equal to or below 548.8 MPa. Correlations between the calculated damage index and the damage progress are proposed.

Stability Analysis of the Reinforced Embankment on Soft Foundations using the Limit Equilibrium Method (한계평형법에 의한 연약지반 보강성토의 안정해석)

  • 고남영;고홍석
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.37 no.5
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    • pp.101-110
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    • 1995
  • The use of geotextile as reinforced materials in Soil structures has become widespread throughout the world. Geotextile reinforcement has been used in retaining walls, slope of embankment and especially soft foundation, etc. In the past, however, its design and construction have been performed empirically. In this study, to investigate of the effect of geotextiles reinforced slope of the embankment on a very soft foundation, a limit equilibrium analysis program calculating the safety factor of embankment on very soft foundation was developed. The study was focussed on such factors as type of geotextile, tensile strength, amount of reinforcement, and inclination of embankment. And the 4imit equilibrium analysis program was written on the basis of Low's slope stability theory with some modification. The following conclusions were drawn from this study. (1) The orientation of reinforcement can be assumed either horizontal or tangential to the slip circle. The factor of safety with tangential reinforcement is larger than that with the horizontal reinforcement. (2) In general, the factor of safety increases, as the slope reduces. However, it is preferable to use geotextiles with higher tensile strength rather than to reduce the slope of the embankment, because it is difficult to adjust the slope as desired. (3) The factor of safety obtained by numerical computation is affected only by the tensile strength, but not by the type of the geotextile.

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Test of Headed Reinforcement in Pullout II: Deep Embedment

  • Choi, Dong-Uk
    • International Journal of Concrete Structures and Materials
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    • v.18 no.3E
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    • pp.151-159
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    • 2006
  • A total of 32 pullout tests were performed for the multiple headed bars relatively deeply embedded in reinforced concrete column-like members. The objective was to determine the minimum embedment depth that was necessary to safely design exterior beam-column joints using headed bars. The variables for the experiment were embedment depth of headed bar, center-to-center distance between adjacent heads, and amount of supplementary reinforcement. Regular strength concrete and grade SD420 reinforcing steel were used. The results of the test the indicated that a headed bar embedment depth of $10d_b$ was not sufficient to have relatively closely installed headed bars develop the pullout strength corresponding to the yield strength. All the experimental variables, influenced the pullout strength. The pullout strength increased with increasing embedment depth and head-to-head distance. It also increased with increasing amount of supplementary reinforcement. For a group of closely-spaced headed bars installed in a beam-column joint, it is recommended to use column ties at least 0.6% by volume, 1% or greater amount of column main bars, and an embedment depth of $13d_b$ or greater simultaneously, to guarantee the pullout strength of individual headed bars over 125% of $f_y$ and ductile load-displacement behavior.