한국건설순환자원학회논문집 (Journal of the Korean Recycled Construction Resources Institute)

한국건설순환자원학회 (Korean Recycled Construction Resources Institute)
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하중 이력에 따른 경량 잔골재 콘크리트의 초음파 특성

Ultrasonic Pulses Characteristics in Lightweight Fine Aggregate Concrete under Various Load Histories

  • 유경석 (철도기술연구원 고속철도연구본부) ;
  • 김지상 (서경대학교 토목건축공학과) ;
  • 김익범 (서울연구원 안전환경연구실)
  • Yoo, Kyung-Suk (High-speed Railroad Systems Research Center, Korea Railroad Research Institute) ;
  • Kim, Jee-Sang (Dept. of Civil & Architectural Engineering, Seokyeong University) ;
  • Kim, Ik-Beam (Safety Environment Research Division, The Seoul Institute)
  • 투고 : 2014.09.12
  • 심사 : 2014.09.24
  • 발행 : 2014.09.30
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초록

본 연구는 비파괴 검사 중 하나인 초음파 펄스 속도법(Ultrasonic Pulse Velocity Method)은 시험 물질의 초음파 펄스의 이동시간을 결정하는 것으로, 지금까지 대부분의 연구는 시간 영역에서 표현된 결과만을 이용하여왔다. 그러나 시간 영역에서 초음파 펄스의 신호는 고속 푸리에 변환(FFT)를 통해 주파수 영역으로 변환할 수 있으며, 보다 유용한 정보를 얻을 수 있어, 그 방법을 활용하고자 한다. 이 논문에서는 경량 잔골재를 사용하여 다양한 하중 이력에 대한 콘크리트의 펄스 속도와 주파수 영역 신호의 변화에 대한 비교를 통해, 일반 콘크리트의 강도식의 적용성 여부, 골재 치환율 별 주파수 변화 양상, 최대주파수 분석 등의 연구를 진행하였다. 초음파 속도 측정과 강도 측정을 통해 경량 잔골재 콘크리트에 기존 압축강도식의 적용성 여부를 판단하였지만, 신뢰도 저하로 기존 제안식의 사용은 어렵다는 것을 확인하였고, 하중이력 상태에서 경량 잔골재를 사용한 콘크리트의 초음파 펄스가 주파수 영역에서 보이는 신호가 보통 콘크리트와 비교하여 차이를 보여주지 않았으며, 응력 증가 추세에 따라 초음파 속도와 최대주파수의 상관관계는 존재하나, 초음파 속도와 최대주파수는 상호 독립적인 관계임을 확인하였다.

One of the widely used NDT(Non-destructive techniques) is the ultrasonic pulse velocity (USPV) method, which determines the travel time of the ultrasonic pulse through the tested materials and most studies were focused on the results expressed in time domain. However, the signal of ultrasonic pulse in time domain can be transformed into frequency domain, through Fast fourier transform(FFT) to give more useful informations. This paper shows a comparison of changes in the pulse velocity and frequency domain signals of concrete for various load histories using lightweight fine aggregates. The strength prediction equation for normal concrete using USPV cannot be used to estimate lightweight fine aggregate concrete strength. The signals in frequency domain of ultrasonic pulse of lightweight fine aggregate concrete does not show any significant difference comparing with those of normal concrete. The increases in stress levels of concrete change the pulse velocities and maximum frequencies, however the apparent relationship between themselves can not be found in this experiment.

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참고문헌

  1. Cho, Chang-Ho. (2008). Calculation of Aging Effects of Ultrasonic Pulse Velocity in Concrete by Non-Destructive Test. Korea institute for Structural Maintenance Inspection Journal, 12(6), 173-179 [in Korean].
  2. Gregor Trtnik., Franci Kavc.ic. and Goran Turk. (2009). Prediction of concrete strength using ultrasonic pulse velocity and artificial neural networks. Ultrasonics, 49, 53-60. https://doi.org/10.1016/j.ultras.2008.05.001
  3. Harun Tanyidizi and Ahmet Coskun. (2008). Determination of the Principal Parameter of Ultrasonic Pulse Velocity and Compressive strength of Lightweight Concrete by Using Variance Method. Russian Journal of Nondestructive Testing, 44(9), 639-646. https://doi.org/10.1134/S1061830908090088
  4. Hong Ki Nam., Lee Han Sol., Kim Joon Il., Han Sang Hoon. and Jung Gyu San. (2012). Estimation of concrete Compressive Strength by Non-Destructive Test. Journal of the Institude of Construction Technology, 31(2), 19-25 [in Korean]. https://doi.org/10.4334/JKCI.2002.14.1.001
  5. J. Alexandre Bogas., M. Gloria Gomes. and Augusto Gomes.(2013). Compressive strength evaluation of structural lightweight concrete by non-destructive ultrasonic pulse velocity method. Ultrasonics, 53, 962-972. https://doi.org/10.1016/j.ultras.2012.12.012
  6. Kim, J.H., Kim, J.S. and Park, J.B., (2010). Internal Damage Assessment of Concrete for Various Load Histories using Ultrasonic Pulse Velocity Method. Proceedings of Korea Concrete institute 2010 Spring Convention, 22(1), 347-348 [in Korean].
  7. Kim, Joo Hyung., Choi, Young Cheol., Jung, Sang Hwa. and Lee, Kwang Myong. (2012). Mixing and Shrinkate Properties of internal curing concrete by lightweight fine aggregate. Journal of the Korean Recycled Construction Resources Institute 2012 fall, 12(2), 177-189 [in Korean].
  8. Kim, M.S., Baek, D.I. and Youm, C.S. (2007) A Study on the Strength Prediction of Crushed Sand Concrete by Ultra-sonic Velocity Method. Korea institute for Structural Maintenance Inspection Journal, 11(4), 71-78 [in Korean].
  9. Lim, Su-Young. (2008). A Study on the Estimation of Compressive Strength of Concrete by Non-Destructive Test. Daegu University, Korea [In Korean].
  10. Manish A. Kewalramani. and Rajiv Gupta. (2006) Concrete compressive strength prediction using ultrasonic pulse velocity through artificial neural networks. Automation in Construction, 15, 374-379. https://doi.org/10.1016/j.autcon.2005.07.003
  11. Mehta, P.K. and Monteiro, P.J.M. (1986). Concrete: microstructure, properties, and materials. McGraw-Hill, U.S.A.
  12. Nagueire, C. (2009). Ultrasonic wave propagation in concrete. VDM-verlag, U.S.A.
  13. RILEM Recommendation NDT 1. (1972). Testing of Concrete by the Ultrasonic Pulse Method. Paris.
  14. Stauffer, J.D., Woodward, C.B. and White, K.R. (2005). Nonlinear ultrasonic testing with resonant and pulse velocity parameters for early damage in concrete. ACI Materials Journal, 102(2), 21-28.
  15. Treiber, M., Kim, J., Qu, J. and Jacobs, L.J. (2010). Effects of sand aggregate on ultrasonic attenuation in cement-based materials. Materials and Structures, 43(1), 1-11.
  16. Wu, T.T. and Lin, T.F. (1998). The stress effect on the ultrasonic velocity variations of concrete under repeated loading. ACI Materials Journal, 95(5), 519-524.
  17. Yang, Keun-Hyeok. (2013). Mix Design of Lightweight Aggregate Concrete and Determination of Targeted Dry Density of Concrete. Journal of the Korea Institute of Building Construction, 13(5), 491-497 [in Korean]. https://doi.org/10.5345/JKIBC.2013.13.5.491