Journal of the Korean Recycled Construction Resources Institute (한국건설순환자원학회논문집)

Korean Recycled Construction Resources Institute (한국건설순환자원학회)
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Analytical Study on Flexural Behavior of Alkali-Activated Slag-Based Ultra-High-Ductile Composite

알칼리활성 슬래그 기반 초고연성 복합재료의 휨거동 해석

  • Received : 2019.05.17
  • Accepted : 2019.06.26
  • Published : 2019.06.30
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Abstract

The purpose of this study is to investigate analytically the flexural behavior of beam reinforced by an alkali-activated slag-based fiber-reinforced composite. The materials and mixture proportion were selected to manufacture an alkali-activated slag-based fiber-reinforced composite with high tensile strain capacity over 7% and compressive strength and tension tests were performed. The composite showed a compressive strength of 32.7MPa, a tensile strength of 8.43MPa, and a tensile strain capacity of 7.52%. In order to analyze the flexural behavior of beams reinforced by ultra-high-ductile composite, nonlinear sectional analysis was peformed for four types of beams. Analysis showed that the flexural strength of beam reinforced partially by ultra-high-ductile composite increased by 8.0%, and the flexural strength of beam reinforced fully by ultra-high-ductile composite increased by 24.7%. It was found that the main reason of low improvement in flexural strength is the low tensile strain at the bottom of beam. The tensile strain at bottom corresponding to the flexural strength was 1.38% which was 18.4% of tensile strain capacity of the composite.

이 연구의 목적은 알칼리활성 슬래그 기반 섬유보강 복합재료를 보 부재의 재료로 활용하였을 때 휨거동을 해석적으로 분석하는 것이다. 7% 이상의 초고연성이 나타날 수 있는 알칼리활성 슬래그 기반 섬유보강 복합재료를 제조하기 위하여 재료 및 배합을 선정하였고, 재료의 압축강도와 인장성능을 평가하였다. 복합재료는 압축강도 32.7MPa, 인장강도 8.43MPa, 인장변형성능 7.52%를 나타내었다. 초고연성 복합재료로 구성된 보의 휨거동을 분석하기 위하여 4가지 단면에 대하여 비선형 단면 층상화 방법을 사용하여 해석을 수행하였다. 해석결과 초고연성 복합재료로 부분적으로 보강된 경우 8.0%, 콘크리트가 복합재료로 전부 치환되어 전체 보강된 경우 24.7%의 휨강도 증진효과가 있는 것으로 나타났다. 휨강도 증진 효과가 크지 않은 이유는 인장 연단의 변형률이 최대 1.38%로 초고연성 복합재료의 인장변형성능의 18.4%밖에 되지 않기 때문인 것으로 나타났다.

Keywords

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Fig. 1. Uniaxial tensile behavior of UHD composite

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Fig. 2. Stress and strain curves of materials for flexural analysis: (a) full scale, (b) compressive behavior, and (c) tensile behavior

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Fig. 3. Sectional view of beams: (a) R-C, (b) R-C+UHD composite, (c) R-UHD composite, and (d) UHD composite(no bar)

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Fig. 4. Moment and curvature curves

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Fig. 5. Neutral axis

Table 1. Properties of slag

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Table 2. Properties of fiber

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Table 3. Mixture proportion

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Table 4. Flexural strength, strain, and neutral axis predicted by analysis

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