Journal of the Korean Recycled Construction Resources Institute (한국건설순환자원학회논문집)

Korean Recycled Construction Resources Institute (한국건설순환자원학회)
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Structural Behavior of 3D Printed Concrete Specimens with Reinforcement

보강재가 있는 3D 프린팅 콘크리트의 구조거동

  • Joh, Changbin (Structural Engineering Research Institute, Korea Institute of Civil Engineering and Building Technology) ;
  • Lee, Jungwoo (Structural Engineering Research Institute, Korea Institute of Civil Engineering and Building Technology) ;
  • Yang, In-Hwan (Department of Civil Engineering, Kunsan National University)
  • 조창빈 (한국건설기술연구원 인프라안전연구본부) ;
  • 이정우 (한국건설기술연구원 인프라안전연구본부) ;
  • 양인환 (군산대학교 토목공학과)
  • Received : 2018.09.04
  • Accepted : 2018.09.11
  • Published : 2018.09.30
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Abstract

This paper examines the structural behavior of 3D printed concrete specimens with focus on the bond between the layers. The tensile bond and flexural strengths were investigated experimentally and compared with those of specimens made by conventional mold casting. The test parameters were the time gap between printing layers and the reinforcement between vertical layers. The results showed the 3D printed specimens had voids between layers and confirmed the strength reduction due to printing time gap and the stress concentration caused by the voids. Most of the reduction in tensile bond strength between layers was due to the stress concentration at least up to certain printing time gap. Moreover, beyond a certain printing time gap (24hours), the additional reduction in tensile bond strength reached a level that could affect the structural behavior. The reinforcement between layers was helpful to increase the ductile behavior which is essential to prevent the sudden collapse of the structure. In addition, the reduction in flexural strength due to the stress concentration by the voids was observed and should be considered in the design of 3D printed wall structures against the lateral load.

본 연구에서는 프린트 층 사이에 부착에 초점을 두고 3D 프린팅 콘크리트의 구조거동 연구를 수행하였다. 3D 프린팅 콘크리트의 부착 및 인장강도 실험을 수행하고 일괄 타설 콘크리트 실험결과와 비교하였다. 실험변수는 콘크리트 층 사이의 프린트 시간차와 철근 보강 여부이다. 콘크리트 층 사이에는 공극이 존재하고 이에 따라, 강도 감소가 발생한다. 층 사이 대부분의 인장부착 강도 감소는 응력 집중과 프린트 시간차에 기인한다. 프린트 시간차가 24시간을 초과할 때 인장부착 강도의 감소는 구조거동에 영향을 미친다. 층 사이 철근 보강은 연성거동 증진에 유용하고 구조물의 갑작스런 파괴를 예방한다. 또한, 공극이 유발한 응력 집중에 기인한 휨 강도 감소는 횡방향 하중을 받는 3D 프린트 벽체 구조물 설계시에 고려되어야 한다.

Keywords

References

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