The Evaluation of Compressive Strength in Cement Mortar using Electromagnetic Properties

전자기 특성을 이용한 시멘트 모르타르의 압축강도 평가

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

Abstract

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.

References

  1. Rhim, H. C., Buyukozturk, O., 'Electromagnetic Properties of Concrete at Microwave Frequency Range', ACI Mater J., Vol. 95, pp. 262-271, 1998
  2. McCarter, W. J., Chrisp, T. M., Starrs, G., Blewett, J., 'Characterization and Monitoring of Cement-Based Systems using Intrinsic Electrical Property Measurements', Cem. Concr. Res., Vol. 33, pp. 197-206, 2003 https://doi.org/10.1016/S0008-8846(02)00824-4
  3. McCarter, W. J., Starrs, G., Chrisp, T. M., 'The Complex Impedance Response of Fly-Ash Cement Revisited', Cem. Concr. Res., Vol. 34, pp. 1837- 1843, 2004 https://doi.org/10.1016/j.cemconres.2004.01.013
  4. Feng, M. Q., Kim, Y. J., De Flaviis, F. D., 'Use of Microwaves for Damage Detection of FRP-Wrapped Concrete Structures', J. of Eng. Mech. ASCE, Vol. 128, pp. 172-183, 2001
  5. Rhim, H. C., Kim, Y. J., Feng, M. Q., Woo, S. K., Song, Y. C., 'Measurements of Electromagnetic Properties of Concrete and Fiber Reinforced Polymer for Nondestructive Testing', US-Korea Joint Seminar/Workshop on Smart Structures Technologies, Sheraton Walker Hill Hotel, Seoul, Korea, September 2, 2004
  6. Korean Standard, Method of test for compressive strength of concrete: KSF 2405, 2005
  7. McCarter, W. J., Starrs, G, Chrisp, T. M., 'Electrical Conductivity, Diffusion, and Permeability of Portland Cement-Based Mortar', Cem. Conc. Res., Vol. 30, pp. 1395-1400, 2000 https://doi.org/10.1016/S0008-8846(00)00281-7
  8. Rhim, H. C., 'Condition Monitoring of Deteriorating Concrete Dams using Radar', Cem. Concr. Res., Vol. 31, pp. 363-373, 2001 https://doi.org/10.1016/S0008-8846(00)00496-8
  9. 임홍철, 정성훈, '비파괴 시험을 위한 콘크리트의 전자기적 특성의 측정', 한국콘크리트학회 논문집, 제12권, 제3호, 2000, pp. 115-123, 2000
  10. Maekawa, K., Chaube, R., Kishi, T., Modeling of Concrete Performance, E&FN SPON, 1999
  11. Halabe, U. B., 'Condition Assessment of Reinforced Concrete Structures Using Electromagnetic Waves', Doctoral thesis, Department of Civil Eng. MIT, Cambridge, 2000
  12. Neville, A. M., Properties of Concrete, Longman, 4th Ed. pp. 272-282, 1998
  13. Halabe, U. B., Sotoodehnia, A. Maser, K. R., and Kausel, E. A., 'Modeling the Electromagnetic Properties of Concrete', ACI Material Journal, Vol. 90, pp. 552-563, 1993
  14. Soutsos, M. N., Bungey, J. H. Millard, S. G., Shaw, M. R. Patterson, 'A. Dielectric Properties of Concrete and Their Influence on Radar Testing', NDT & E Inter., Vol. 34, pp. 419-425, 2001 https://doi.org/10.1016/S0963-8695(01)00009-3
  15. Glanvile, J. and Nevile, A. Prediction of Concrete Durability, Proceedings of STATS 21st Anniversary Conference, E&FN SPON, pp. 16-36, 1995