• 제목/요약/키워드: Repairing Materials

검색결과 211건 처리시간 0.022초

탄소섬유그리드 보강 휨부재의 거동에 대한 실험적 연구 (An Experimental Study on the Behavior of Carbon Fiber Grid Reinforced Flexural Members)

  • 박제용;안동준;정상균;윤순종
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 1999년도 추계학술발표대회 논문집
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    • pp.154-159
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    • 1999
  • In this paper we present tile results of an experimental investigation on the physical and mechanical properties of carbon fiber grid, polymer mortar, and carbon fiber grid reinforced plain concrete flexural members. In order to repairing and reinforcing damaged and/or deteriorated existing concrete structural members, new materials have been developed and utilized in the construction industries. But the physical and mechanical behaviors of the material are not well understood. To use the material effectively various aspects of the material must be throughly investigated analytically as well as experimentally. In this investigation we found the physical and mechanical properties of carbon fiber grid and polymer mortar which are directly utilized in the repair and reinforcement design of damaged or deteriorated concrete structures. In addition, we also investigate the strengthening effect of carbon fiber grid on the plain concrete flexural test specimens. It was found that the material can be used to repair and strengthen the concrete structures effectively.

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CaO-SiO2-PEEK 생체복합체의 제조와 in-vitro 특성평가 (Preparation of CaO-SiO2-PEEK bio-composites and in-vitro Evaluation)

  • 김일용;조성백;김종옥;신종우;이성호;박중근;김택남
    • 한국재료학회지
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    • 제14권4호
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    • pp.287-292
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    • 2004
  • A bio-composites were prepared by mechanical mixing with bioactive sol-gel derived $CaO-SiO_2$ and organic PEEK for bone repairing hybrid materials. The composites were characterized by in-vitro test. A bonelike apatite was formed on the surface of all bio-composites in SBF test. The cell morphology and adhesion on the surface of the composites having below 30% PEEK were clearly observed in L929 cell experiment.

하이브리드 방법에 의한 세라믹 성형재료의 탄성계수 결정 (The Determination of Elastic Constant for Ceramic Forming Material by Hybrid Method)

  • 박명균;구본성
    • 대한안전경영과학회지
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    • 제7권1호
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    • pp.211-222
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    • 2005
  • The ceramic forming materials are getting more important recently since they are used widely in repairing metal structures, welded metal structures and mechanical components etc. The determination of elastic constants for ceramic coating materials takes much time and efforts in experiment due to the brittleness of ceramic material itself. The aim of this research is to determine the Young's Modulus for ceramic metal coating material. In order to achieve the goal, the hybrid method which uses impulse hammer technique for experimental method and modal analysis of finite element method for computational method was used. The results show good agreement with existing experimental data on Young's Modulus.

Experimental Investigation of Shear Behavior of Reinforced Concrete Beam Repaired with DFRCC at Cover Thickness

  • 김장호;;;임윤묵
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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    • pp.577-580
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    • 2004
  • Recently, DFRCCs (Ductile Fiber Reinforced Cementitious Composites), materials with remarkable ductility when compared to ordinary fiber-reinforced concrete (FRC), have been developed and studied actively in the US, Japan, and many European countries. The transformation of failure behavior from brittle to ductile is achieved by incorporating with fracture mechanics concept especially micro-mechanical models approach of cementitious composite materials in manufacturing ordinary fiber-reinforced composites. The purpose of this study is to accurately understand the shear behavior of DFRCC repaired RC beams. Using a four-point bending test, the shear strengths and shear stress-deflection relations of DFRCC repaired RC specimens are obtained. The results show that DFRCC can be effectively used for repairing materials for concrete structures.

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4각형 고강도 콘크리트 기둥 단면 변형을 통한 CFS Jacketing 보강방법 개발 (Development of CFS Jacketing Retrofit Method for Rectangular High Strength Concrete Columns by Cross Sectional Shape Modification)

  • 이종길;김장호;박석균;김진근
    • 한국구조물진단유지관리공학회 논문집
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    • 제14권6호
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    • pp.153-161
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    • 2010
  • 1970년대에 콘크리트를 기반으로 지어진 많은 구조물과 빌딩은 안전성과 사용성을 고려하여 무수히 많은 연구를 현재까지 진행해 왔으나, 설계강도 보다 낮은 최대강도를 보이고 있다. 현재 노후화된 콘크리트 구조물들에 대한 다양한 보수 보강 공법이 개발되어 적용되고 있지만 기존 연구들은 구조물의 특성에 대해서는 고려하지 않고, 단지 기존 부재와 보수 재료의 부착에 관한 연구와 기존 부재를 효과적으로 보강하기 위한 새로운 방법을 개발하는 연구는 미흡한 실정이다. 따라서 본 연구는 보수 보강 재료를 이용한 효율적인 강도증진 방법에 대한 연구, 보강 재료와 기존 부재 사이의 거동에 대해 부족했던 연구를 보완하고자 한다. 또한 고강도 콘크리트는 높은 압축강도를 발현하기 때문에 부재의 단면을 축소시킬 뿐만 아니라 구조물의 자중 또한 감소시킬 수 있으므로 거대한 구조물 건설에 사용되고 있다. 고강도 콘크리트의 사용이 점차 증가하는 추세이지만 고강도 콘크리트를 이용한 구조물의 보수 보강에 대한 방법 연구 역시 미진한 실정이다. 따라서 본 연구에서는 효과적인 고강도 콘크리트 기둥에 대한 보수 보강 방법을 개발하고자 한다. 본 연구에서는 사각단명 형상을 가진 기둥을 팔각단면으로 형상 변형을 통해 CFS로 보수 보강하여 단면 형상이 변함에 따른 효과를 파악하고, CFS로 보강된 고강도 콘크리트(HSC) 기둥의 강도 증대 효과와 파괴 거동에 대해 파악하고자 한다.

RC구조물 접착 보수·보강 공법의 박리와 연관한 재료의 변형 거동 분석 (Deformation Behavior Investigation of Materials by Debonding Failure in Adhesion and Repairing-strengthening Methods of RC Construction)

  • 한천구;변항용;박용규
    • 한국구조물진단유지관리공학회 논문집
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    • 제11권5호
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    • pp.89-98
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    • 2007
  • 본 연구에서는 RC구조물의 접착 보수 보강 재료의 박리와 연관한 변형 거동에 대하여 검토하였다. 응력-변형곡선에서 최대응력 이후 항복을 일으킬 수 있는 변형량은 바탕재인 시멘트 모르터의 경우 $2.0{\times}10^{-3}$, 콘크리트는 $1.3{\times}10^{-3}$ 전후이고, 접착제인 에폭시수지 $0.8{\times}10^{-3}$, 폴리머 시멘트 모르터 $2.5{\times}10^{-3}$이며, 보강재인 강판과 탄소봉은 2.5와 $9.1{\times}10^{-3}$정도인 것으로 밝혀졌다. 온도변화에 따른 선팽창계수는 바탕재인 시멘트 모르터 및 콘크리트의 경우 $10{\mu}{\varepsilon}/{^{\circ}C}$전후인데 비하여, 접착제인 에폭시 수지는 $41{\sim}54{\mu}{\varepsilon}/{^{\circ}C}$, 폴리머 시멘트 모르터는 $-0.5{\sim}0.7{\mu}{\varepsilon}/{^{\circ}C}$, 보강재인 강판은 바탕재료와 비슷하지만, 탄소섬유는 $-1.7{\mu}{\varepsilon}/{^{\circ}C}$로 제일 작은 값이었다. 특히 바탕재료인 콘크리트와 에폭시수지 접착제간에는 온도변화에 따른 선팽창계수 차이가 크게 발생하였는데, 에폭시 수지 종류에 따라 약간의 차이는 있지만, $20{\sim}35{^{\circ}C}$이상의 온도차가 발생하는 조건이면 에폭시수지 접착제는 콘크리트 접착면에서 자연적으로 박리 할 수도 있는 것으로 밝혀졌다.

Evaluation of the rat tissue reaction to experimental new resin cement and mineral trioxide aggregate cement

  • Yang, Won-Kyung;Ko, Hyun-Jung;Kim, Mi-Ri
    • Restorative Dentistry and Endodontics
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    • 제37권4호
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    • pp.194-200
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    • 2012
  • Objectives: New resin cement (NRC) has been developed as a root repairing material and the material is composed of organic resin matrix and inorganic powders. The aim of this study was to compare the rat subcutaneous tissue response to NRC and mineral trioxide aggregate (MTA) cement and to investigate the tissue toxicity of both materials. Materials and Methods: Sixty rats received two polyethylene tube-implants in dorsal subcutaneous regions, MTA and NRC specimens. Twenty rats were sacrificed respectively at 1, 4 and 8 wk after implantation and sectioned to 5 ${\mu}m$ thickness and stained with Hematoxylin-Eosin (H-E) or von-Kossa staining. The condition of tissue adjacent to the implanted materials and the extent of inflammation to each implant were evaluated by two examiners who were unaware of the type of implanted materials in the tissues. Data were statistically analyzed with paired t-test (p < 0.05). Results: In specimens implanted with both NRC and MTA, severe inflammatory reactions were present at one wk, which decreased with time. At eighth wk, MTA implanted tissue showed mild inflammatory reaction, while there were moderate inflammatory reactions in NRC implanted tissue, respectively. In NRC group, von-Kossa staining showed more calcification materials than MTA group at eighth wk. Conclusions: It was concluded that the calcium reservoir capability of NRC may contribute to mineralization of the tissues.

RC 구조물 보수용 에폭시 레진의 물리.화학적 특성 고찰 (A Studt on the Physical and Chemical Properties of Epoxy Resin in RC Structures)

  • 김도겸;유영찬;이장화;박승범
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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    • pp.571-578
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    • 1997
  • In the repair and repair works, epoxy resins are widely used as repair materials. The successful concrete repairs and retrofit works depends on the quality of the repair and retrofit materials. Although many materials for the repairs and retrofit have been developed in many contries, information on the repair methods are somewhat limited. Futhermore, the repairs and retrofit methods are also largely dependent on those froms in other developed contries, it is necessary to initiate rather fundamental repair-related research. The purpose of this study is to investigate th physical and mechanical properties of epoxy resin which is commonly used in repairing concrte crack in RC structures. The basic physical properties such as specific gravity, gel point and shrinkage ratio as well as the mechanical properties such ad the tensile and compressive strength, elastic modulus were acquired by the standard test method (KS code). For the test results, the great deviations of physical and mechanical properties among the test materials were discovered and is, therefore, recommended that careful attentions should be give in selecting the epoxy resin by considering the characteristics of the repair materials and repair works.

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Performance Evaluation of Sprayed Ductile Fiber-Reinforced Mortar as a Repairing Material

  • Kang, Su-Tae;Koh, Kyung-Taek;Ryu, Gum-Sung;Kim, Jin-Soo;Han, Cheon-Goo
    • International Journal of Concrete Structures and Materials
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    • 제2권1호
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    • pp.27-33
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    • 2008
  • Most of existing repair materials have some shortcomings such as brittle fracture, imperfect interface bonding and marked difference in modulus of elasticity compared with the structures. These problems make their repair inefficient. Some researches on using a fiber-reinforced mortar as an alternative to enhance the efficiency have been carried out recently. This paper presents the results of an experimental study on the performance of sprayed PVA fiber-reinforced mortar as a repair material. We evaluated its mechanical properties, durability and strengthening effect. This study shows that the sprayed PVA fiber-reinforced mortar is remarkably effective as a repair material.

섬유강화 복합재료에서 결함의 보강재에 의한 강도 평가 (The Strength Evaluation of Reinforced Flaw by Stiffener in Woven Fiber Reinforced Composite Plates)

  • 이문철;최영근;이택순
    • 한국해양공학회지
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    • 제8권1호
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    • pp.96-104
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    • 1994
  • The use of advanced composite materials has grown in recent years in aerospace and other structures. Out of various kinds of repairing methods the one selecteh for this study is an idealized case which simulates a situation where a damaged laminate has been repaired by drilling a hole and therefter plugging the hole with reinforcement. Two typesof reinforcement are investigated ;adhesively bonged plug reinforcement or snug-fit unbonded plug in the hole. For each case of reinforcement, four different sizes of hole diameter and three types of reinforcing material(steel, aluminum, plexiglass) are employed for investigation. The experiment are mainloy forced on the evaluation of ultimate strength of laminate with reinforced hole in comparison to its counterpart with the open hole.

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