Non-destructive wood moisture content measurements using computed tomography scanning

Author(s): Owe Lindgren
Paper category: Proceedings
Book title: Proceedings on International RILEM Conference on Materials, Systems and Structures in Civil Engineering Conference segment on Moisture in Materials and Structures
Editor(s): Kurt Kielsgaard Hansen, Carsten Rode and Lars-Olof Nilsson
ISBN: 978-2-35158-178-0
e-ISBN: 978-2-35158-179-7
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 322 -331
Total Pages: 10
Language : English

Abstract: Computed tomography (CT-) scanning offers many advantages compared to other measurement methods of moisture content. It is a non-contact, don-destructive and tree dimensional measurement. Using medical scanners the measurements are also fast, in the order of 1 second.
However, measurements on wood are not straightforward. A CT-image is a map of X-ray attenuation coefficients, which are strongly dependent on density. However, the coefficients are also depending on chemical composition. For example a wooden sample showing a density of 500 kg/m3 not containing any water shows a higher coefficient than a sample containing 450 kg/m3 of wood and 50 kg/m3 of water. Therefore two measurements are necessary; a first image of the unknown distribution and a second image taken as a reference at a known moisture content level.
Furthermore, wood itself absorbs water into the wood material, which causes swelling and distortions. This has been handled by using image processing. During the last year tests have been performed using dual energy CT-scanning showing promising results. Here instead of comparing before and after images above, images achieved at two different X-ray energies are compared. This is a much faster method as conditioning to a known moisture content level is not necessary.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00