Density and Moisture Profile Evolution during Timber Drying by CT Scanning Measurements

Abstract

Timbers of 105 × 105 mm² in cross section and 1000 mm long were computed tomography (CT) scanned with a commercial unit in equal time steps during a drying cycle. The study aimed to convert the scanning numbers into wood density values, observe the changes that occur during the dehydration process, and, from these, differentiate moisture content as a function of time and space. The reference for calculating the moisture content of each image pixel was the oven-dry wood scan. Analysis of the results allowed visualizing the water distribution, the mechanism of water removal, as well as check formation. Although only a single drying run was analyzed and a limited number of timbers were scanned, the results revealed trends and thus show promise, so further research is urged because it may lead to a better understanding of water movement and check formation in wood during kiln drying.

Keywords:

• Amabilis fir
• CT scanning
• Density
• Drying
• Image pixels
• Moisture content

ACKNOWLEDGMENTS

This research was financially supported by a Natural Sciences and Engineering Research Council of Canada Collaborative Research and Development grant and by a Research Grant-in-Aid from FP Innovations, Forintek Division. The help of CT scanner technologist Gabor Szathmary is greatly appreciated.