Suitability of time domain reflectometry for monitoring moisture in building materials

M.C. Phillipson, P.H. Baker, M. Davies, Z. Ye, G.H. Galbraith, R.C. McLean

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Time Domain Reflectometry (TDR) has been used since the 1980s for measuring the moisture content of soils. The principle of TDR is based on measuring the reflection time of an electromagnetic signal sent down a set of waveguides that are inserted into the material. This paper reports research work examining the suitability of TDR for measuring the moisture content of building materials. Results suggest that TDR is an effective way of monitoring relative changes in the moisture content. Measurement of absolute moisture content is more complicated as it requires a calibration function, and the existing empirical relationships used in the soil sciences consistently overestimate the moisture content. A semi-empirical calibration relationship has been found to offer a better approach to absolute moisture content evaluation with TDR. Practical application: This paper reports research work examining the suitability of TDR for application to the measurement of the moisture content of building materials. It finds that TDR can rapidly identify changes in the relative moisture content and may therefore be suited to monitoring the long-term moisture behaviour of a building material in situ. Application of the technique to the measurement of the absolute moisture content is more difficult; further work is needed to address the accuracy of absolute measurements.
Original languageEnglish
Pages (from-to)261-272
Number of pages11
JournalBuilding Services Engineering Research and Technology
Volume29
Issue number3
DOIs
Publication statusPublished - 2008

Keywords

  • TDR
  • soil water content
  • building materials

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