1887
Volume 8, Issue 6
  • ISSN: 1569-4445
  • E-ISSN: 1873-0604

Abstract

ABSTRACT

The moisture content is a critical parameter for most physical and chemical pathologies of timber and, in the case of structural wood, a can be dangerous for any load‐bearing construction. The complexity of evaluating while timber is in use by means of the current methods (oven‐drying and resistance wood meter) led us to test non‐destructive techniques to evaluate this parameter on site.

With this in mind, measurements with two non‐destructive techniques, ground‐penetrating radar (GPR) and ultrasound, were carried out on joists of Ait. from their initial green state until the point of hygroscopic equilibrium moisture content. In particular, the analysis presented in this paper focuses on the capacity of each technique to register the velocity variations of their waves during the timber drying process.

Prior to the GPR analysis, it was necessary to distinguish between differences in the propagation velocity of electromagnetic waves attributable to the wood anisotropy and those due to variations in . The propagation velocity of the electromagnetic waves was always found to be lower when the electrical field was parallel to the grain of the wood than when it was perpendicular to it. However, when the field was perpendicular, its direction whether radial or tangential, did not significantly affect the . The direct measurements illustrate the ability of the GPR technique to characterize the of timber as a clear decrease in the resulted in an increase in the . A strong correlation was obtained between the two parameters with coefficients of determination, .

Longitudinal elastic wave velocities were assessed by means of a ultrasound technique during the timber drying process. Despite the fact that the increased with the decreasing of each joist, the determination coefficient between these two variables was very low.

The analysis presented in this paper is a successful application of the GPR technique to the study of wood’s physical properties and has a promising future for the non‐destructive, on‐site analysis of timber .

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2010-08-01
2020-07-05
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References

  1. ArriagaF., PerazaF., EstebanM., BobadillaI. and GarcíaF.2002. Intervención en estructuras de madera.Editorial AITIM.
    [Google Scholar]
  2. BrayD.E., TangW., BidigareB., CornwellL.R. and KozaczekK.1997. Identification of ultrasonic echo source in 4140 steel bars used for an oil field tool.Materials Evaluation55, 897–902.
    [Google Scholar]
  3. BucurV.1995. Acoustic of Wood.CRC Press Inc.
    [Google Scholar]
  4. BucurV.2003. Non‐destructive Characterization and Imaging of Wood.Springer Verlag.
    [Google Scholar]
  5. DukeS.1990. Calibration of ground penetrating radar and calculation of attenuation and dielectric permittivity versus depth. PhD thesis, Colorado School of Mines.
    [Google Scholar]
  6. FujiiY., NoguchiM., ImamuraY. and TokoroM.1990. Using acoustic‐emission monitoring to detect termite activity in wood.Forest Products Journal40, 34–36.
    [Google Scholar]
  7. GrosseC.U. and ReinhardtH.W.2002. Ultrasound technique for quality control of cementitious materials.15th World Conference on NDT, Rome, Italy, Expanded Abstracts.
    [Google Scholar]
  8. HuismanJ.A., SnepvangersJ.J.J.C., BoutenW. and HeuvelinkG.B.M.2003. Monitoring temporal development of spatial soil water content variation: Comparison of ground penetrating radar and time domain reflectometry.Vadose Zone Journal2, 519–529.
    [Google Scholar]
  9. KabirM.F.2001. Prediction of ultrasonic properties from grain angle.Journal of the Institute of Wood Science15, 235–246.
    [Google Scholar]
  10. KabirM.F., KhalidK.B., DaudW. M. and AzizS.H.A.1997. Dielectric properties of rubber wood at microwave frequencies measured with an open‐ended coaxial line.Wood and Fiber Science29, 319–324.
    [Google Scholar]
  11. KabirM.F., DaudW.M., KhalidK. and SidekH.A.A.1998. Dielectric and ultrasonic properties of rubber wood. Effect of moisture content, grain direction and frequency.Holz als Roh‐ und Werkstoff56, 223–227.
    [Google Scholar]
  12. KabirM.F., DaudW.M., KhalidK.B. and SidekA.H.A.2000. Equivalent circuit modeling of the dielectric properties of rubber wood at low frequency.Wood and Fiber Science32, 450–457.
    [Google Scholar]
  13. KabirM.F., DaudW.M., KhalidK.B. and SidekH.A.A.2001. Temperature dependence of the dielectric properties of rubber wood.Wood and Fiber Science33, 233–238.
    [Google Scholar]
  14. KarsulovicJ.T., LeonL.A. and GaeteL.2000. Ultrasonic detection of knots and annual ring orientation in Pinus radiata lumber.Wood and Fiber Science32, 278–286.
    [Google Scholar]
  15. LaurensS., BalayssacJ.P., RhaziJ. and ArliguieG.2002. Influence of concrete relative humidity on the amplitude of ground‐penetrating radar (GPR) signal.Materials and Structures35, 198–203.
    [Google Scholar]
  16. LaurensS., BalayssacJ.P., RhaziJ., KlyszG. and ArliguieG.2005. Nondestructive evaluation of concrete moisture by GPR: Experimental study and direct modelling.Materials and Structures38, 827–832.
    [Google Scholar]
  17. LuntI.A., HubbardS.S. and RubinY.2005. Soil moisture content estimation using ground‐penetrating radar reflection data.Journal of Hydrology307, 254–269.
    [Google Scholar]
  18. MaierhoferC., LeipoldS. and WiggenhausereH.1998. Investigations of the influence of moisture and salt content on the dielectric properties of brick materials using radar. 7th International Conference on Ground Penetrating Radar, Lawrence, Kansas, USA, Expanded Abstracts.
    [Google Scholar]
  19. NorimotoM. and YamadaT.1972. The dielectric properties of wood VI, on the dielectric properties of chemical constituents of wood and the dielectric anisotropy of wood.Wood Research52, 30–43.
    [Google Scholar]
  20. PérezV.2001. Radar del subsuelo. Evaluación en arqueología y en patrimonio histórico‐artístico. PhD thesis, Universidad Politécnica de Cataluña.
    [Google Scholar]
  21. PeyskensE., PourcqM., StevensM. and SchalckJ.1984. Dielectric properties of softwood species at microwave frequencies.Wood Science Technology18, 267–280.
    [Google Scholar]
  22. RossR.J.2002. Inspection of timber structures using stress wave timing nondestructive evaluation tools.Forest Products Society, Nondestructive Evaluation of Wood, 139‐142.
    [Google Scholar]
  23. RothC.H., MalickiM.A. and PlaggeR.1992. Empirical‐evaluation of the relationship between soil dielectric‐constant and volumetric water‐content as the basis for calibrating soil‐moisture measurements by TDR.Journal of Soil Science43, 1–13.
    [Google Scholar]
  24. SahinH. and NürgulA.2004. Dielectric properties of hardwood species at microwave frequencies.Journal of Wood Science50, 375–380.
    [Google Scholar]
  25. SandozJ.L.1989. Grading of construction timber by ultrasound.Wood Science and Technology23, 95–108.
    [Google Scholar]
  26. SbartaiZ.M., LaurensS., BalayssacJ.P., BallivyG. and ArliguieG.2006. Effect of concrete moisture on radar signal amplitude.ACI Materials Journal103, 419–426.
    [Google Scholar]
  27. SchmalzB., LennartzB. and WachsmuthD.2002. Analyses of soil water content variations and GPR attribute distributions.Journal of Hydrology267, 217–226.
    [Google Scholar]
  28. ToppG.C., DavisJ.L. and AnnanA.P.1980. Electromagnetic determination of soil‐water content‐measurements in coaxial transmission‐lines.Water Resources Research16, 574–582.
    [Google Scholar]
  29. TorgovnikovG.I.1993. Dielectric Properties of Wood and Wood‐based Materials.Springer Verlag.
    [Google Scholar]
  30. UNE‐EN 13183‐1:2002
    UNE‐EN 13183‐1:2002 . Moisture content of a piece of sawn timber. Part 1: Determination by oven dry method.
    [Google Scholar]
  31. UNE‐EN 13183‐2:2002.
    UNE‐EN 13183‐2:2002.Moisture content of a piece of sawn timber. Part 2: Estimation by electrical resistance method.
    [Google Scholar]
  32. ViriyametanontK., LaurensS., KlyszG., BalayssacJ.P. and ArliguieG.2008. Radar survey of concrete elements: Effect of concrete properties on propagation velocity and time zero.NDT & E International41, 198–207.
    [Google Scholar]
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