Nondestructive characterization of dry heat-treated fir (Abies Alba Mill.) timber in view of possible structural use

Straže, Aleš (author), Fajdiga, Gorazd (author), Gospodarič, Bojan (author)

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.

• Language: English
• Keywords: heat treatment, wood, structural changes, nondestructive testing, ultrasound, Euler-Bernoulli, modulus of elasticity
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2018
• Number of pages: 12 str.
• Numbering: Vol. 9, iss. 12, art. 776
• PID: 20.500.12556/RUL-132000
• UDC: 630*8
• ISSN on article: 1999-4907
• DOI: 10.3390/f9120776
• COBISS.SI-ID: 2986633
• Publication date in RUL: 08.10.2021

Record is a part of a journal

• Title: Forests
• Shortened title: Forests
• Publisher: MDPI
• ISSN: 1999-4907
• COBISS.SI-ID: 3872166

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 15.12.2018

Secondary language

• Language: Slovenian
• Keywords: toplotna obdelava, les, strukturne spremembe, testiranje, ultrazvok

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P4-0015
• Name: Les in lignocelulozni kompoziti

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0182
• Name: Razvojna vrednotenja