Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Application of Time Domain Reflectometry to Estimate Curing Process of Cementitious Grout

시계열반사계를 이용한 시멘트계열 지반보강재의 양생과정 평가

  • Jun, Minu (Dept. of Civil & Environmental Engineering, Gachon Univ.) ;
  • Cho, Hyunmuk (Dept. of Civil & Environmental Engineering, Gachon Univ.) ;
  • Lee, Eun Sang (Dept. of Civil & Environmental Engineering, Gachon Univ.) ;
  • Hong, Won-Taek (Dept. of Civil & Environmental Engineering, Gachon Univ.)
  • 전민우 (가천대학교 토목환경공학과) ;
  • 조현묵 (가천대학교 토목환경공학과) ;
  • 이은상 (가천대학교 토목환경공학과) ;
  • 홍원택 (가천대학교 토목환경공학과)
  • Received : 2024.05.29
  • Accepted : 2024.06.05
  • Published : 2024.06.30
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Abstract

To realize stable use of ground treated with cementitious materials, the curing process must be evaluated. In this study, a time domain reflectometry (TDR) measurement system was employed to evaluate the curing process of cementitious grout based on the electromagnetic property. A coated probe was manufactured to prevent electrical connection between the electrodes by the electrically conductive cementitious grout, and a calibration process was performed to estimate the actual relative permittivity using the coated probe. To assess the curing process of cementitious grout using the TDR measurement system, cementitious grout with added retarder was prepared with a water-to-cement ratio of 45%. A preliminary measurement was conducted immediately after pouring the cementitious grout into the mold to test the applicability of the coated probe, and TDR signals and relative permittivity were measured at 3~288 hours of curing time. The experimental results demonstrate that the relative permittivity of the cementitious grout immediately after pouring was greater than 100, decreased rapidly over time, and converged to approximately 13.8 at 144 hours, which is considered the fully cured time. This findings of this study demonstrate that the TDR measurement system with a coated probe is applicable to electrically conductive materials. In addition, the TDR measurement system can be used effectively to monitor the curing process of cementitious grout based on electromagnetic properties.

시멘트계열 재료를 이용한 지반보강 시 처리지반의 안정적 이용을 위하여 해당 재료의 양생과정 평가가 요구된다. 본 연구에서는 전자기적 물성 기반 시멘트 그라우트의 양생과정 평가를 위하여 시계열반사계(TDR) 측정시스템을 적용하였다. 시멘트 그라우트의 높은 전도성으로 인한 프로브 내 전극간 전기적 연결을 방지하기 위하여 코팅 프로브를 제작하였으며, 코팅 프로브로부터 실제 비유전율 평가를 위한 보정실험이 수행되었다. 코팅 프로브가 적용된 TDR 측정시스템으로부터 시멘트 그라우트의 양생과정을 평가하고자 지연제가 첨가된 물시멘트비 45%의 초속경시멘트 그라우트가 준비되었으며, 몰드 내 타설 직후 예비측정 및 배합 후 3~288시간 경과 시점에서 TDR 신호를 수집, 비유전율을 평가하였다. 실험 결과, 타설 직후의 시멘트 그라우트는 100 이상의 높은 비유전율 상태를 나타내었으나 양생시간이 경과함에 따라 급격한 감소 경향을 보였으며, 양생 144시간 시점부터의 비유전율은 약 13.8로 수렴하여 해당 시간을 양생 완료시점으로 판단하였다. 본 연구에서 이용된 코팅 프로브 TDR 측정시스템은 전도성 재료에 대한 적용성과 더불어 전자기적 물성 기반 시멘트계열 지반보강재 양생과정 모니터링에 활용될 수 있을 것이라 기대된다.

Keywords

Acknowledgement

이 성과는 정부(과학기술정보통신부)의 재원으로 한국연구재단의 지원을 받아 수행된 연구임(RS-2024-00337686).

References

  1. Cambefort, H. (1977), "The Principles and Applications of Grouting", Quarterly Journal of Engineering Geology and Hydrogeology, Vol.10, No.2, pp.57-95. https://doi.org/10.1144/GSL.QJEG.1977.010.02.01
  2. Cataldo, A., De Benedetto, E., Cannazza, G., Piuzzi, E., and Pittella, E. (2017), "TDR-based Measurements of Water Content in Construction Materials for in-the-field Use and Calibration", IEEE Transactions on Instrumentation and Measurement, Vol.67, No.5, pp.1230-1237.
  3. Chen, W., Shen, P., and Shui, Z. (2012), "Determination of Water Content in Fresh Concrete Mix based on Relative Dielectric Constant Measurement", Construction and Building Materials, Vol.34, pp.306-312. https://doi.org/10.1016/j.conbuildmat.2012.02.073
  4. Cheng, D. K. (1989), Field and wave electromagnetics, Pearson Education India.
  5. Chung, C. C., Lin, C. P., Wang, K., Lin, C. S., and Ngui, Y. J. (2016), "Improved TDR Method for Quality Control of Soil-nailing Works", Journal of Geotechnical and Geoenvironmental Engineering, Vol.142, No.1, 06015011.
  6. Hasan, M. I. and Yazdani, N. (2014), Ground penetrating radar utilization in exploring inadequate concrete covers in a new bridge deck, Case Studies in Construction Materials, 1.
  7. Heimovaara, T. J. (1993), "Design of Triple-wire Time Domain Reflectometry Probes in Practice and Theory", Soil Science Society of America Journal, Vol.57, No.6, pp.1410-1417. https://doi.org/10.2136/sssaj1993.03615995005700060003x
  8. Hoekstra, P. and Delaney, A. (1974), "Dielectric Properties of Soils at UHF and Microwave Frequencies", Journal of Geophysical Research, Vol.79, No.11, pp.1699-1708.
  9. Hong, W. T., Kang, S., and Lee, J. S. (2015), "Application of Ground Penetrating Radar for Estimation of Loose Layer", Journal of the Korean Geotechnical Society, Vol.31, No.11, pp.41-48. https://doi.org/10.7843/kgs.2015.31.11.41
  10. Hong, W. T., Jung, Y. S., Lee, J. S., and Byun, Y. H. (2015), "Development and Application of TDR Penetrometer for Evaluation of Soil Water Content of Subsoil", Journal of the Korean Geotechnical Society, Vol.31, No.2, pp.39-46.
  11. Karlovsek, J., Schwing, M., Chen, Z., Wagner, N., Williams, D. J., and Scheuermann, A. (2016), "Dielectric Measurement Method for Real-time Monitoring of Initial Hardening of Backfill Materials Used for Underground Construction", Journal of Geophysics and Engineering, Vol.13, No.2, S19-S27.
  12. Kikuchi, K., Igari, T., Mito, Y., and Utsuki, S. (1997), "In Situ Experimental Studies on Improvement of Rock Masses by Grouting Treatment", International Journal of Rock Mechanics and Mining Sciences, Vol.34, No.3-4, 138-e1.
  13. Kim, J. H., Yi, M. J., Park, S. G., and Farooq, M. (2007), "Resistivity Monitoring for Assessing Cement Grouting Effect", Near Surface 2007-13th EAGE European Meeting of Environmental and Engineering Geophysics (pp. cp-30). European Association of Geoscientists & Engineers.
  14. Liu, J. L., Xu, J. Y., and Lu, S. (2017), Investigations on microwave deicing effects on graphite-modified concrete, RSC advances, Vol.7, No.62, pp.39237-39243. https://doi.org/10.1039/C7RA04920J
  15. McIsaac, G. (2010), Time domain reflectometry measurement of water content and electrical conductivity using a polyolefin coated TDR probe (Master's thesis, University of Waterloo).
  16. Mojid, M. A., Wyseure, G. C., and Rose, D. A. (1998), "The Use of Insulated Time-domain Reflectometry Sensors to Measure Water Content in Highly Saline Soils", Irrigation Science, Vol.18, pp. 55-61. https://doi.org/10.1007/s002710050044
  17. Secanellas, S. A., Hernandez, M. G., Segura, I., Morata, M., and Anaya, J. J. (2019), "A System Designed to Monitor in-situ the Curing Process of Sprayed Concrete", Construction and Building Materials, Vol.224, pp.823-834.
  18. Nonveiller, E. (2013), Grouting theory and practice, Elsevier.
  19. Saha, O., Boulfiza, M., and Wegner, L. D. (2020), "Tracking the Hydration of Antifreeze Treated Cement Paste at Subfreezing Temperatures Using the TDR Technique", Construction and Building Materials, Vol.262, 119915.
  20. Staub, M., Laurent, J. P., Morra, C., Stoltz, G., Gourc, J. P., and Quintard, M. (2008), "Calibration of Time-domain Reflectometry Probes to Measure Moisture Content in Municipal Solid Waste in Laboratory-scale Cells", Geo-Environmental Engineering, pp.199-205.
  21. Venkateswarlu, B. and Tewari, V. C. (2014), "Geotechnical Applications of Ground Penetrating Radar (GPR)", Jour. Ind. Geol. Cong, Vol.6, No.1, pp.35-46.
  22. Xie, X., Zhai, J., and Zhou, B. (2021), "Back-fill Grouting Quality Evaluation of the Shield Tunnel Using Ground Penetrating Radar with Bi-frequency Back Projection Method", Automation in Construction, Vol.121, 103435.
  23. You, S. K., Ahn, H., Kim, Y. H., Han, J. G., Hong, G., and Park, J. J. (2019), "A Numerical Study on the Occurrence Scope of Underground Cavity and Relaxation Zone Considering Sewerage Damage Width and Soil Depth", Journal of the Korean Geotechnical Society, Vol.35, No.1, pp.43-53.
  24. Zegelin, S. J., White, I., and Jenkins, D. R. (1989), "Improved Field Probes for Soil Water Content and Electrical Conductivity Measurement Using Time Domain Reflectometry", Water Resources Research, Vol.25, No.11, pp.2367-2376.  https://doi.org/10.1029/WR025i011p02367