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TDR measurement of moisture content in aerated concrete

Hansen, E. and Hansen, M. H.
2002
6th Symposium on Building Physics in the Nordic Countries, Trondheim, Norway, Jun 17

Hansen, E. and Hansen, M. H., (2002), "TDR measurement of moisture content in aerated concrete", 6th Symposium on Building Physics in the Nordic Countries, Trondheim, Norway, Jun 17.
Abstract:
"...Measurement of moisture profiles in porous building materials are made possible using the TDR-technique (Time Domain Reflectometry). This is based on the velocity or transit time measurement of an electromagnetic wave in a material sample.

r = 1 in non-magnetic materials and therefore the velocity of the electromagnetic wave c is only dependent on the dielectric constant ¦Å.

The dielectric constant expresses the influence of a non-conductive material on electrical forces. There is a large difference between the dielectric constant of water and of dry, porous materials. At 20 ¡ãC ¦Å r ¡Ö 80 for water, while ¦Å r ¡Ö 5 for porous materials. This difference is responsible for the fact that the dielectric constant of a moist porous material is mainly a function of the moisture content. Therefore the moisture content can be determined by means of the TDR-technique by measuring the velocity c of the electromagnetic wave."
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Author Information and Other Publications Notes
Hansen, E.
Danish Building and Urban Research
  1. Experimental investigation of the hygrothermal performance of insulation materials  
Hansen, M. H.
Technical University of Denmark, Dept of Civil Engineering, Lyngby, Denmark
  1. Building-related symptoms and molds: a two-step intervention study
  2. Health evaluation of volatile organic compound (VOC) emissions from wood and wood-based materials
  3. Measuring moisture content in wood with built in probes 20+ years experience
  4. Moisture in combined concrete timber-frame walls without vapour barrier
  5. Numerical method for calculating latent heat storage in constructions containing phase change material
  6. On the influence of cavity ventilation on moisture content in timber frame walls
  7. Protection of wood by design
  8. Symptoms associated to work in a water damaged school building  


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