• Title, Summary, Keyword: FR-ECC

Search Result 5, Processing Time 0.025 seconds

An Experimental Study on the Durability and Load Carrying Capacity of RC Structure Repair System Using FR-ECC (고인성 내화보수모르터(FR-ECC)를 활용한 RC 구조물 보수공법의 내구성능 및 내하력에 관한 실험적 연구)

  • Kim, Jeong Hee;Lim, Seung Chan;Kim, Jae Hwan;Kwon, Yung Jin
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.16 no.2
    • /
    • pp.75-86
    • /
    • 2012
  • This paper presents some research results on the shrinkage characteristics and frost resistance before and after cracking of FR-ECC(Fire Resistance-Engineered Cementitious Composite). Also, a waterstop performance and exfoliating resistance of multi-layer lining specimens using FR-ECC and flexural performance of beam member by repaired FR-ECC are estimated in this paper. Experimental results indicate that the plastic shrinkage crack and length change ratio of FR-ECC have been reduced as compared with that of the existing repair mortar, and that its crack resistance on the dry shrinkage is improved under the confining stress. As well as FR-ECC has been great in the frost resistance and its tensile properties under the cracked state have been not reduced by freezing and thawing reaction. In addition, beam member by repaired FR-ECC have been increased in the flexural properties such as initial crack moment, yeild moment, and its crack width has been controled in a stable by the frexural failure.

An Experimental Study on the Performance Evaluation of Repair Method of RC Structure Using Fire Resistance Engineered Cementitious Composites(FR-ECC) (고인성 내화·보수 모르타르를 활용한 RC구조물 보수공법의 성능평가에 관한 실험적 연구)

  • Kim, Jeong-Hee;Kim, Jae-Whan;Park, Sun-Gyu;Kwon, Young-Jin
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.13 no.6
    • /
    • pp.88-96
    • /
    • 2009
  • In this Study, FR-ECC(Fire Resistance Engineered Cementitious Composites) in which at same time it can improve the endurance and fire-resistance efficiency of a Structure was developed, and the experimental study such as thermal characteristic, Fire-resistance efficiency, and etc was performed for using FR-ECC as the repair materials for building and civil Structure. Moreover, it was evaluated about the field applicability of FR-ECC. As a result, FR-ECC is superior to the existence fire resistance repair mortar in strength and durability property. Also, FR-ECC was exposed to have the characteristic of being excellent than existence fire resistance mortar in the field applicability.

Behavior of Fire Resistance Engineered Cementitious Composites(FR-ECC) under Fire Temperature (화재 온도를 받는 고인성.고내화성 시멘트 복합체의 거동)

  • Han, Byung-Chan;Kwon, Young-Jin;Kim, Jae-Hwan
    • Journal of the Korea Concrete Institute
    • /
    • v.19 no.2
    • /
    • pp.189-197
    • /
    • 2007
  • Concrete tunnel lining must be designed to having the fireproof performance because the lining are sometimes exposed to very high temperature due to traffic accident. Such fire temperature may cause explosion of concrete, or collapse of tunnel structure. The purpose of this study is to obtain the fundamental fireproof behavior of fire resistance-engineered cementitious composites(FR-ECC) under fire temperature in order to use the fire protection material in tunnel lining system. The present study conducted the experiment to simulate fire temperature by employing 2 types of FR-ECC and investigated experimentally the explosion and cracks in heated surface of these FR-ECC. Employed temperature curve were hydro carbon(HC, ECl) criterion, which are severe in various criterion of fire temperature. The numerical analysis is carried out the nonlinear transient heat flow analysis and verified against the experimental data. The complex features of behavior in fire conditions, such as thermal expansion, plasticity, cracking or crushing, and material properties changing with temperature are considered. By the use of analytical model, the concrete tunnel subjected to fire loads were analyzed and discussed. With comparison of current concrete materials and FR-ECC, the experimental and analytical results of FR-ECC shows the better fire resistance performance than the other.

A study on the fire resistance method using FR-ECC in long tunnel (고인성내화모르터(FR-ECC)를 사용한 장대터널 내화안전대책에 관한 연구)

  • Kim, Se-Jong;Kim, Dong-Jun;Kwon, Young-Jin
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.13 no.1
    • /
    • pp.9-18
    • /
    • 2011
  • The spalling phenomenon occurs in high-strength concrete when several factors such as sharp temperature increase, high water content, low water/cement ratio and local stress concentration in material combine in the concrete material. On the basis of the factors, the preventing methods from the spalling are known as reduction of temperature increase, preventing of concrete fragmentation and fast drying of internal moisture. In this study, the reduction of temperature increase was proposed as the most effective spalling-preventing method among the spalling-preventing methods. Engineered cementitious composite for fireproof and repair materials was developed in order to protect the new and existing RC structures form exterior deterioration factors such as fire, cloride ion, etc. This study was carried out to estimate the fire-resisting performance of high strength concrete slab or tunnel lining by repaired engineered cementitious composite (ECC) or fiber reinforcement cemetitious composite (FRCC) under fire temperature curve. and them we will descrike the result of HIDA tunnel in Japan.

Isolation Enhancement by the Non-connected Ground Structure for the Mobile Phone MIMO Antenna (비접촉 접지구조에 의한 휴대폰 MIMO 안테나 격리도 향상)

  • Jo, Young-Sang;Son, Tae-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.65 no.6
    • /
    • pp.1032-1037
    • /
    • 2016
  • In this paper, the method of isolation enhancement for the mobile phone MIMO antenna of LTE class 40(2300~2400MHz) was studied. Design of MIMO antenna was based on the hybrid antenna that operates both a monopole and an IFA(Inverted F Antenna). A structure for the isolation enhancement which controls induced electric field on the ground plane is located between MIMO antenna, and was not connected with the ground but apart 0.3mm. A MIMO antenna that operates on class 3~40(1710~2400MHz) of LTE service bands and a structure for the isolation enhancement at the class 10 band were designed. VSWR measurement of implemented antenna on the FR4 board showed within 3:1 at entire design bands, and isolation between antennas at the class 40 band was less than -30dB. Isolation was enhanced more than 20dB by the studied structure. ECC(Envelope Correlation Coefficient) for MIMO performance was under 0.1, and antenna average gain and efficiency measured in the anechoic chamber were -4.28~-1.40dBi and 37.32~72.36% respectively.