20.500.12556/RUL-132000 Nondestructive characterization of dry heat-treated fir (Abies Alba Mill.) timber in view of possible structural use The use of heat-treated timber for building with wood is of increasing interest. Heat treatment improves the durability and dimensional stability of wood; however, it needs to be optimized to keep wood’s mechanical properties in view of the possible structural use of timber. Therefore, dry vacuum heat treatment varying the maximum temperature between 170 °C and 230 °C was used on fir (Abies alba Mill.) structural timber, visually top graded according to EN 338, to analyze its final weight loss, hygroscopicity, CIELAB color, and dynamic elastomechanical properties. It turned out that weight loss and total color difference of wood positively correlates with the increasing intensity of the heat treatment. The maximum 40% reduction of the hygroscopicity of wood was already reached at 210 °C treatment temperature. The moduli of elasticity in longitudinal and radial direction of wood, determined by ultrasound velocity, increased initially up to the treatment temperature of 210 °C, and decreased at higher treatment temperature. Equally, the Euler-Bernoulli modulus of elasticity from free-free flexural vibration of boards in all five vibration modes increased with the rising treatment temperature up to 190 °C, and decreased under more intensive treatment conditions. The Euler-Bernoulli model was found to be valid only in the 1st vibration mode of heat-treated structural timber due to the unsteady decrease in the evaluated moduli of elasticity related to the increasing mode number. heat treatment wood structural changes nondestructive testing ultrasound Euler-Bernoulli modulus of elasticity toplotna obdelava les strukturne spremembe testiranje ultrazvok true false true Angleški jezik Slovenski jezik Članek v reviji 2021-10-08 10:21:57 2021-10-08 10:21:58 2022-09-12 04:10:35 0000-00-00 00:00:00 2018 0 0 12 str. iss. 12, art. 776 Vol. 9 2018 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 630*8 1999-4907 10.3390/f9120776 2986633 RAZ_Straze_Ales_2018.pdf RAZ_Straze_Ales_2018.pdf 1 8D2E0F3A1EA432EA648C92793F4FC984 b7968fd8c9952387f77ad9b225fe609298678e2fe0f447e83e1768ca36b226de 0fb26ff2-2811-11ec-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=149488 https://www.mdpi.com/1999-4907/9/12/776 1 82114c2f-2810-11ec-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=149487 Biotehniška fakulteta 0 0 0