Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
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Study on Characteristics of Controlled Low Strength Material Using Time Domain Reflectometry

시간영역반사법을 이용한 유동성 채움재의 특성 연구

  • Han, Woojin (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Lee, Jong-Sub (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Byun, Yong-Hoon (Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign) ;
  • Cho, Samdeok (Korea Institute of Civil Engineering and Building Technology) ;
  • Kim, Juhyong (Korea Institute of Civil Engineering and Building Technology)
  • Received : 2016.02.11
  • Accepted : 2016.03.21
  • Published : 2016.04.01
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Abstract

The hydration process of Controlled Low Strength Material (CLSM) used for backfill is the primary factor to determine the construction period. The objective of this study is to monitor the hydration process of CLSM using the Time Domain Reflectometry (TDR) and to establish the relationship between dielectric constant and compressive strength. The CLSM specimen is composed of cement, flyash, silt, sand, accelerator, and water. The material characteristics of the CLSM including flow, unit weight, compressive strength are investigated. To measure the dielectric constant of the CLSM during the curing time, TDR probe incorporated with a mold and a reflectometer are used. Experimental results show that the dielectric constant remains constant at early stage, and then decreases as the curing time increases. In addition, the dielectric constant is related to the compressive strength in inverse power function. This paper suggests that the TDR technique may be used as a non-destructive testing method in order to estimate the compressive strength of the CLSM mixture under construction.

기존 뒤채움재의 대체방안으로 고려되는 유동성 채움재(Controlled Low Strength Material, CLSM)의 경화 특성 및 강도발현은 시공기간을 결정하는 주요 요소이다. 본 연구에서는 시간영역반사법(Time Domain Reflectometry, TDR)을 이용하여 유전상수를 도출함으로써 CSLM의 경화 특성을 모니터링하고, 산정된 유전상수와 일축압축강도간의 관계를 분석해보고자 하였다. CLSM 시료는 시멘트, 비회, 실트, 모래, 급결제 및 물로 배합되었으며 배합된 시료의 플로우, 단위중량, 일축압축강도와 같은 재료 특성을 조사하였다. 양생 기간 동안 CLSM의 유전율 특성을 모니터링하기 위하여 TDR 프로브가 설치된 몰드 및 Reflectometer를 이용하여 측정시스템을 구성하였다. 실험결과 유전상수는 양생 초기에 일정한 값을 유지하다, 시간이 진행됨에 따라 점차 감소하는 것으로 나타났다. 또한, 일축압축강도와 유전상수를 회귀분석한 결과 두 물성 사이에는 반비례적인 거듭제곱함수의 관계가 있음을 보여주었다. 본 연구에서 제안한 시간영역반사법을 이용한 CLSM의 특성 모니터링은 일축압축강도를 추정할 수 있는 현장 비파괴시험기법으로 효과적으로 사용될 수 있을 것으로 기대된다.

Keywords

References

  1. ACI Committee 229 (1999), Controlled low-strength materials (CLSM), American Concrete Institute, 229R-99, pp. 1-15.
  2. ASTM C191 (2013), Standard test methods for time of setting of hydraulic cement by vicat needle, American Society for Testing and Materials.
  3. ASTM C403 (2008), Standard test method for time of setting of concrete mixtures by penetration resistance, American Society for Testing and Materials.
  4. ASTM D 6103 (2004), Standard test method for flow consistency of controlled low-strength material (CLSM), American Society for Testing and Materials.
  5. Benson, C. and Bosscher, P. (1999), Time-domain reflectometry in geotechnics: a review, Nondestructive and Automated Testing for Soil and Rock Properties, STP 1350, ASTM, W. Marr and C. Fairhurst, Eds., pp. 113-136.
  6. Fellner-Feldegg, H. (1969), The measurement of dielectrics in the time domain, J. Phys. Chem. Vol. 73, pp. 616-623. https://doi.org/10.1021/j100723a023
  7. Han, C. G., Hwang, Y. S., Lee, S. H. and Kim, G. D. (2004), Properties of strength development of concrete at early age with water cement ratio and cement factor, Architecture, Architectural Institute of Korea, Vol. 20, No. 4, pp. 77-84 (in Korean).
  8. 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.
  9. Janoo, V., Korhonen, C. and Hovan, M. (1999), Measurement of water content in Portland cement concrete, Journal of Transportation Engineering, Vol. 125, No. 3, pp. 245-249. https://doi.org/10.1061/(ASCE)0733-947X(1999)125:3(245)
  10. Kim, H. (2002), Enhanced performance of high early strength concrete with regulated set cement, master thesis, Konkuk University, pp. 5-16 (in Korean).
  11. Lee, H. K., Lee, K. M., Kim, Y. H., Yim, H. and Bae, D. B. (2004), Ultrasonic in-situ monitoring of setting process of highperformance concrete, Cem Concr Res, Vol. 34, pp. 631-40. https://doi.org/10.1016/j.cemconres.2003.10.012
  12. Li, Z., Wei, X. and Li, W.(2003), Preliminary interpretation of Portland cement hydration process using resistivity measurements. ACI Materials Journal, Vol. 100, No. 3, pp. 253-257.
  13. O'Connor, K. M. and Dowding, C. H. (1999), Geomeasurements by pulsing TDR cables and probes, pp. 424.
  14. Qin, L. and Li, Z. (2008), Monitoring of cement hydration using embedded piezoelectric transducers, Smart Mater Struct, Vol. 17, No. 5, pp. 1-6.
  15. Ryu, J. H. and Jeon, H. K. (2008), A study on development method for early-strength concrete, Proceedings of the korea Concrete Institute, Vol. 20, No. 1, pp. 681-684 (in Korean). https://doi.org/10.4334/JKCI.2008.20.6.681
  16. Sayers, C. M. and Dahlin, A. (1993), Propagation of ultrasound through hydrating cement pastes at early times, Adv Cem Based Mater, Vol. 1, pp. 12-21. https://doi.org/10.1016/1065-7355(93)90004-8
  17. Topp, G. C., Davis, J. C. and Annan, A. P. (1980), Electromanetic determination of soil water content : measurements in coaxial transmission lines, Water Resources Research, Vol. 16, No. 3, pp. 574-582. https://doi.org/10.1029/WR016i003p00574
  18. Zhu, J., Kee, S. H., Han, D. and Tsai, Y. T. (2011a), Effects of air voids on ultrasonic wave propagation in early age cement pastes, Cem Concr Res, Vol. 41, pp. 872-881. https://doi.org/10.1016/j.cemconres.2011.04.005
  19. Zhu, J., Tsai, Y. T. and Kee, S. H. (2011b), Monitoring early age property of cement and concrete using piezoceramic bender elements. Smart Mater Struct, Vol. 20, No. 11, pp. 1-6.

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