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A Study on Evaluating the Compressive Strength Development of Concrete Mixed with Non-sintered Hwangto Admixture by an Ultrasonic Method

비소성 황토 결합재를 혼합한 콘크리트의 강도 발현 평가를 위한 초음파 속도법의 검토

  • Kim, Jeong-Wook (Department of Architectural Engineering, Chungnam University) ;
  • Kim, Won-Chang (Department of Fire and Disaster Prevention, Semyung University) ;
  • Kim, Gyu-Yong (Department of Architectural Engineering, Chungnam University) ;
  • Lee, Tae-Gyu (Department of Fire and Disaster Prevention, Semyung University)
  • Received : 2022.11.15
  • Accepted : 2022.11.30
  • Published : 2023.02.20

Abstract

In this study, the mechanical properties of concrete mixed with non-sintered hwangto(NHT) as an alternate material for cement were evaluated, and the compressive strength prediction equation of concrete based on ultrasonic pulse velocity analysis was proposed. Cement replacement rates for mixed NHT were set to 0, 15, and 30%, and design compressive strength was set to 30 and 45MPa to evaluate the effect on the amount of cement and NHT powder. The mechanical properties items analyzed were compressive strength, ultrasonic pulse velocity, and elastic modulus, and were measured on days 1, 3, 7, and 28. As the replacement rate of NHT increased, the mechanical properties tended to decrease. In addition, as a result of analyzing the correlation between compressive strength and ultrasonic pulse velocity, the correlation coefficient(R2) showed a high relationship(R2=0.95) on concrete mixed with NHT.

본 연구에서는 시멘트 대체 재료로서 비소성 황토(NHT)를 혼합한 콘크리트의 역학적 특성을 평가하였으며, 초음파 속도 분석을 통한 콘크리트의 강도 예측식을 제안하였다. 혼합된 NHT의 시멘트 치환율을 0, 15 및 30%로 설정하였으며, 시멘트 및 NHT의 분체량에 대한 영향을 평가하기 위해 목표 강도를 30 및 45MPa로 설정하였다. 평가한 항목은 압축 강도, 초음파 속도 및 탄성계수로 설정하였으며, 재령 1, 3, 7 및 28일마다 설정한 항목을 측정하였다. 실험 결과, NHT 치환율이 증가함에 따라 역학적 특성은 감소하는 경향을 보였으며. 또한, 압축 강도와 초음파 속도의 상관관계 분석 결과 상관계수(R2)는 NHT를 혼합한 콘크리트의 경우 약 0.95로 높은 관계성을 보였다.

Keywords

Acknowledgement

This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT)(No.2022R1F1A1073333).

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