• Title/Summary/Keyword: 고내구성

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Durability of High Strength Concrete according to the amount of Admixture (혼화재의 사용량에 따른 고강도 콘크리트 내구성)

  • Kim, Dong-Baek;Lee, In-Duk;Lee, Jae-Won;Kim, Jong-Hoon
    • Proceedings of the Korean Society of Disaster Information Conference
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    • 2022.10a
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    • pp.301-302
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    • 2022
  • 최근 들어 염해, 콘크리트의 탄산화, 동결융해 등의 열화요인 의하여 발생할 수 있는 콘크리트의 내구성에 대한 다양한 연구가 진행되고 있는데, 이러한 열화요인은 독립적이 아닌 복합열화의 형태로 작용하게 되는데, 열화현상을 저감하는 한 방편으로 플라이애쉬와 같은 혼화재를 사용하디도 한다. 플라이애쉬는 유동성 증진을 통한 내구성의 향상과, 수화열 저감을 통한 균열감소 및 장기강도 증진 등의 효과가 있으며, 시멘트를 대체함으로써 경제적인 효과를 유발하는 장점도 가지고 있다. 그러나 플라이애쉬는 품질편차가 크고, 경우에 따라서 미연탄소분에 의한 AE제 흡착 등으로 인한 콘크리트의 내구성 및 강도를 저하시킬 수 있는 요소를 내포하고 있으므로 사용 시 주의가 필요하다. 본 연구에서는 열화를 저감하고, 내구성을 갖는 고강도 콘크리트를 제조하기 위하여 다양한 배합비의 플라이애쉬 혼입 콘크리트를 실험한 후 그 결과를 분석·고찰함으로써 내구성 콘크리트의 제작 시 혼화재로서의 적용성 및 타당성을 검증하고자 하며, 플라이애쉬를 내구성 재료로 그 활용을 극대화하고, 다양한 플라이애쉬의 사용량과 물/결합재비(W/B)에 대하여 내구성이 높은 고강도 콘크리트 제조방법을 범용화하며, 그 품질을 평가하는 것을 목적으로 한다.

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Investigation on the Properties of Mortar Corresponding to a High Durability Admixture (고내구성 혼화재 첨가에 따른 모르타르의 특성 검토)

  • Kim, Jong-Baek;Bae, Jun-Yeong;Cho, Sung-Hyun;Woo, Seung-Min;Jun, Sung-Yong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.443-444
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    • 2009
  • This study investigated the development of high durability concrete under an oceanic region through the examination and comparison of the fundamental property and diffusion of chloride ion to apply a high durability admixture on the mortar.

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Engineering Properties of High Durable Concrete using High Durability Admixture for Mega Foundation (고내구성 혼화재 사용에 따른 Mega Foundation용 고내구성 콘크리트의 공학적 특성)

  • Kim, Jong-Baek;Bae, Jun-Yeong;Cho, Sung-Hyun;Woo, Seung-Min;Jun, Sung-Yong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.215-216
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    • 2010
  • This study investigated the development of high durability concrete under an oceanic region through the examination and comparison of the fundamental property and diffusion of chloride ion to apply a high durability admixture on the concrete.

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Characteristics of Chloride Penetration in Cracked Flexural Member using Durable Materials (고내구성 재료를 사용한 휨부재의 균열에 따른 염화물 침투 특성)

  • Jin, Sang-Ho;Kim, Il-Sun;Kim, Myung-Yu;Yang, Eun-Ik;Yi, Seong-Tae
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.401-404
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    • 2008
  • Crack is a penetration path of harmful material such as chloride ion, and causes a serious deterioration in durability. So, the characteristics of chloride penetration are investigated for the cracked flexural concrete members using high-durable materials. For these, the flexural crack of beam specimen is introduced by transverse loading. And, Rapid Chloride Penetration Test (RCPT) and Long-term chloride penetration test are carried out to compare the chloride penetration depth. From test results when crack is happened, the chloride penetration resistance of the durable member was superior than that of the normal member. Blast furnace slag concrete member has a excellent chloride penetration resistance in long-term chloride penetration test.

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Service Life Evaluation of High Durability Concrete in Caisson Structure (케이슨 구조물 고내구성 콘크리트 내구수명 평가)

  • Yoo, Jo-Hyeong;Kim, Woo-Jae;Hong, Seok-Beom
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.11a
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    • pp.42-43
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    • 2014
  • In order to ensure the construction of sustainable reinforced concrete structures, durability evaluation of Caisson structures before construction should be carried out. In this paper, a service life evaluation technique using a safety factor determined by a reliability theory for Caisson structures subjected to chloride attack is proposed.

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Evaluation of Corrosion Resistance using Electro-chemical Methods for the High-Durability Concrete exposed to Marine Condition (해양환경에 노출된 고내구성 콘크리트의 전기화학적기법을 이용한 부식저항성 평가)

  • Yang, Eun-Ik;Kim, Myung-Yu;Lee, Dong-Gun;Han, Sang-Hun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.4
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    • pp.320-328
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    • 2007
  • The durability of marine concrete structures is severely degraded by corrosion due to seawater attack and diffusion of chloride in concrete. The deduction of durability causes high repair cost for maintenance of marine concrete structure. So, the applicability of high-durable materials is investigated to improve the durability in marine concrete structures. For these, the characteristics of corrosion prevention of marine concrete structures mixed with the mineral admixtures(SF, FA and BFS), the modified steel(stainless and coating steel), and corrosion inhibitors are evaluated using electro-chemical methods. As a results of this study, it is quantified for the effect of promotion of durability by high-durability materials in marine concrete structures.

A Development of concrete Pavement Material with Low Shrinkage and Reflection, High Strength and Performance (저수축 저반사 고강도 고내구성 콘크리트 포장재료 개발)

  • Kim, Hyo-Sung;Nam, Jeong-Hee;Eum, Ju-Yong;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.11 no.1
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    • pp.13-24
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    • 2009
  • This study developed a high strength and performance concrete pavement material with low shrinkage and reflection of sunlight. Based on the literature review, a new mix-design of applying flash ash to improve the strength and performance of the concrete as well as to reduce the dry shrinkage is suggested. In addition, adding black pigment to reduce the reflection and technique of applying OAG (Optimized Aggregate Gradation) is also included. The result of the laboratory experiment indicates that the brightness and the reflection, which depends on the ratio of black pigment addition, did not deviate from the normal range. When OAG is considered for the mix-design, the strength and performance of the concrete improved greatly. In addition, the mix-design using fly ash reduced the dry shrinkage of concrete and improved the resistance to the permeation of chloride ion. Furthermore, the mix-design, which uses fly ash (25% replacement) and black pigment (3% addition) with the application of OAG, is found to be the most effective mix to reduce the shrinkage and reflection as well as improving the strength and performance of the concrete. The result of an economic analysis indicates that the initial construction cost of this proposed mix is more expensive than that of normal concrete pavement material. However, it can be more economic in the long run because the normal concrete pavement material is likely to cost more due to higher probability of maintenance and repair and higher social cost due to traffic accident, etc.

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Performance Based Design for High Curability Concrete (성능중심형 고내구성 콘크리트의 배합설계)

  • Kim, S.S.;Park, K.P.;Lee, J.B.
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.969-974
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    • 2008
  • This study was carried out to investigate the service life of reinforced concrete structures for durability design. The service life has three aspects physical service life, functional service life, and social service life, and that a structures are normally demolished to end its service life when either the functional or social service life is over before the physical service life comes to end an end. In the future, it is very important that durability design shall be performed establishing design service life and the unallowable state of deterioration in the course of design service life.

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Fundamental Study on High Strength and High Durability Cement Concrete Pavement: Part II Strength and Durability Evaluations (시멘트콘크리트 포장의 고강도 고내구성을 위한 기초 연구 : Part II 최적배합콘크리트의 강도 및 내구특성 분석)

  • Yun, Kyong-Ku;Park, Cheol-Woo;Hong, Seung-Ho
    • International Journal of Highway Engineering
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    • v.11 no.3
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    • pp.51-60
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    • 2009
  • This study investigates the fresh state characteristics, strength, chloride ion penetration resistance and freeze-thaw resistance of the suggested high strength-high durability cement concrete pavement. The required workability and air content could be achieved by using an appropriate admixtures. However its dosage should be carefully determined through field trial batches. Compressive strength increased with the increased cement content and, in particular, high cement volume concrete continuously developed strength up to 90 days. No clear relationship, however, existed between flexural strength and cement content. Chloride penetration resistance seemed as a function of curing age rather than the cement content. Freeze-thaw resistance test was conducted using two different coolants, tap water and 4% NaCl solution. When the tap water was used no severe damage was observed up to 300 cycles regardless the air content. Under 4% NaCl solution, specimens of 326kg/$m^3$ cement content showed severe damage with surface scaling. Based on the experimental investigations herein, it is highly recommended that the cement content be greater than 400kg/$m^3$ for strength-high durability cement concrete pavement structures.

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An Experimental Study on the Freeze-Thaw Resistance of High-Strength Light Weight Aggregate Concrete (고강도 경량골재콘크리트의 동결융해 저항성에 대한 실험적 연구)

  • 한상묵;최세규;김생빈
    • Magazine of the Korea Concrete Institute
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    • v.10 no.1
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    • pp.125-132
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    • 1998
  • 경량골재 콘크리트의 내구성과 경제성에 대한 인식 부족으로 조경재료나 인공토양 둥 구조부재 이외의 분야에 사용되고 있는 국내 실정에 비해서, 구미 여러나라에서는 고강도 경량골재를 장지간 교량과 고충건물에 사용하고 있다. 경량골재 콘크리트는 구조물의 재료비 단순비교에 있어서도 경제성이 있을 뿐만 아니라, 자중감소로 인한 구조적, 기하학적 장점도 있으며, 또한 고강도 경량골재의 개발로 경량골재가 가지고 있는 여러 문제점을 해소하여 사용성과 내구성에 있어서 보통골재 콘크리트와 큰 차이가 없는 상황이다. 그러나국내에서 생산된 경량골재는 닫힌 공극보다 열린 공극을 많이 내포하고 있어 수분흡수가 많고, 특히, 동결융해에 대한 내구성에 취약한 문제점을 가지고 있다. 본 논문에서는 내동해성 향상을 위해 10종류의 고강도 경량골재 콘크리트 공시체를 제작하여 실리카 흄, 물.시멘트비, AE제, 강섬유 등을 실험 변수로 하여동결융해 실험을 수행하였다. 연구결과 실리카흄, 물.시멘트 비는 어느 정도 내동해성을 향상시키지만 근본적인 해결방안이 되지 못하며, AE제를 첨가한 공시체와 강섬유를 사용한 공시체는 동결융해 내구성 지수가 90%이상으로 측정되어 내동해성을 개선시킬 수 있는 요소로 나타났다.