전자기 특성을 이용한 시멘트 모르타르의 압축강도 평가

The Evaluation of Compressive Strength in Cement Mortar using Electromagnetic Properties

  • 김동백 (한경대학교 토목공학과) ;
  • 권성준 (얼바인 주립대학교 토목공학과)
  • Kim, Dong-Baek (Department of Civil Engineering, Hankyong National University) ;
  • Kwon, Seung-Jun (Department of civil and Environmental Engineering, University of California)
  • 발행 : 2008.06.30

초록

NDT(Non-Destructive Testing Evaluation) using electromagnetic(EM) properties can be used for evaluation of physical performance in cement-based materials. In this study, a technique for strength evaluation in cement mortar is proposed through the measured EM properties(conductivity and dielectric constant). For this research, cement mortar specimens with 5 W/C ratios are made for evaluation of compressive strength and they are also utilized for tests of EM properties in the range of $0.2{\sim}20GHz$ frequency considering exposure condition and curing period. The averaged conductivity and dielectric constant in $5{\sim}20GHz$ frequency are reduced to $83{\sim}93%$ and $81{\sim}87%$, respectively with increasing water to cement ratios. Through the linear regression analysis, relationships between EM properties and results from the compressive strength are obtained, which shows higher correlated factor($0.93{\sim}0.94$) in the specimens exposed to room condition. The gradients in dielectric constant for strength results is measured to be higher than those in conductivity by $3.9{\sim}5.1$ times. The results from dielectric constant in room condition shows the most efficient relation for evaluation of strength.

키워드

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