Ultrasonic technique for evaluation of initial stadium of wood degradation in exterior conditions without ground contact

Abstract

The experiment evaluate the possibility of using non-destructive measure techniques of the mechanical properties of wood using ultrasonic to determine the initial stages of degradation by biotic and abiotic factors in the outdoors without ground contact. Nine tree species were tested: spruce, pine, Douglas fir, larch, oak, black locust, maple, poplar and alder. Test specimens were exposed to the exterior according to EN 927-3, Prague-Suchdol in the Czech Republic. Measuring changes in velocity of ultrasonic using the apparatus Ultrasonic Timer and moisture content change were measured after 1, 2, 3, 4 and 6 months. Certain ways of detecting the initial stages of damage have been demonstrated to trees oak, larch and spruce. The initial stages of damage by molds at non-durable maple, alder and poplar had not a clear impact on the decrease in the speed of ultrasonic, as well as hairline surface cracks at the Douglas fir.

Biological Durability of Acetylated Hornbeam Wood with Soil Contact in Hungary

“…In this research, a field test, specifically an in-ground test was used, where the wood was partly in contact with the soil, and the impact of atmospheric and biological factors was direct. Non-destructive methods such as visual assessment, macroscopic evaluation, density and mass loss, sound (sonic tomography), optical methods (X-ray tomography), microscopy, radiography, or destructive methods such as the pick/splinter test or strength tests can all assess wood degradation [1,2].…”