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A Study on the Analysis of Concrete Vertical form Demolding Timing Considering the Relationship between the Type of Coarse Aggregate and Ultrasonic Pulse Velocity

굵은 골재의 종류와 초음파 속도의 관계성을 고려한 콘크리트 수직 거푸집 해체 시점 분석에 관한 연구

  • Nam, Young-Jin (Department of Fire and Disaster Prevention, Semyung University) ;
  • Kim, Won-Chang (Department of Fire and Disaster Prevention, Semyung University) ;
  • Choi, Hyeong-Gil (School of Architecture, Kyungpook National University) ;
  • Lee, Tae-Gyu (Department of Fire and Disaster Prevention, Semyung University)
  • Received : 2023.10.24
  • Accepted : 2023.11.09
  • Published : 2023.12.20

Abstract

This research assesses the mechanical properties of concrete, utilizing both normal and lightweight aggregates, through measurements of compressive strength and ultrasonic pulse velocity. The study observed that concrete with normal aggregates exhibited higher compressive strength in its initial stages, whereas concrete with lightweight aggregates showed increased strength over time, likely attributed to the higher water absorption rate of lightweight aggregates. Ultrasonic pulse velocity generally registered higher in normal aggregate concrete, barring a specific duration, presumably due to variations in the internal pore structure of the aggregates. The correlation coefficient(R2) for the strength prediction equation, derived from the relationship between compressive strength and ultrasonic pulse velocity, exceeds 0.95. This high correlation suggests that the predictive equation based on these experimental findings is a reliable method for estimating concrete strength.

본 연구에서는 보통 및 경량 굵은 골재를 사용한 콘크리트의 역학적 특성을 평가하기 위해 압축강도와 초음파 속도를 측정하였다. 압축강도에서는 재령 초기에서 보통골재 콘크리트가 높은 경향을 나타냈으나 시간 경과에 따라 경량골재 콘크리트가 높아지는 것을 알 수 있으며, 경량골재의 특징 중 높은 흡수율의 영향이라고 판단된다. 초음파 속도에서는 일정 시간을 제외하고 대부분 보통골재가 높은 경향을 나타냈으며, 골재의 내부 공극의 차이라고 판단된다. 압축강도와 초음파 속도의 상관관계를 통한 예측식의 상관계수(R2)가 0.95를 상회하며, 본 실험을 통한 예측식으로 강도 예측의 신뢰성이 높다고 판단된다.

Keywords

Acknowledgement

This research was funded by the Korea Agency for Infrastructure Technology Advancement (KAIA) grant funded by the Korean government(MOLIT)(grant number RS2021-KA162704).

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