Bending performance of thermo-hydro-mechanically densified poplar wood : effects of ultrasonic pretreatment and thermal posttreatment at different compression ratios

Veizović, Marko (author), Todorović, Nebojša (author), Straže, Aleš (author), Milić, Goran (author)

Thermo-hydro-mechanical (THM) densification is an effective method for improving the mechanical performance of low-density, fast-growing hardwoods such as poplar. This study examined the bending performance of THM-densified poplar wood at different compression ratios (CR = 0%, 50%, 60%, and 65%), with emphasis on the effects of ultrasonic pretreatment (US) and thermal modification posttreatment (TM), applied individually and in combination. A paired sampling design was used to reduce material variability, and modulus of rupture (MOR) and modulus of elasticity (MOE) were evaluated using linear mixed-effects models (LMM). Bending tests were performed in accordance with EN 310:1993. Increasing the compression ratio led to substantial increases in MOR and MOE; compared with non-densified specimens, MOR increased by approximately 240% and MOE by about 140% at CR = 65%, confirming densification as the dominant factor controlling bending performance. US did not affect non-densified wood but significantly enhanced MOR and MOE after densification, particularly at CR = 50%. In contrast, TM consistently reduced MOR and, to a lesser extent, MOE across all compression ratios. The results demonstrate that the bending performance of densified poplar wood is governed by both compression ratio and compression-dependent treatment effects

• Language: English
• Keywords: wood modification, plantation hardwoods, compression ratio, modulus of rupture, modulus of elasticity, density–property relationship
• Work type: Scientific work
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Publication date: 23.02.2026
• Year: 2026
• Number of pages: Str. 1-18
• Numbering: Vol. 17, iss. 2 [article no. 284]
• PID: 20.500.12556/RUL-179744
• UDC: 630*8
• ISSN on article: 1999-4907
• DOI: 10.3390/f17020284
• COBISS.SI-ID: 269289987
• Publication date in RUL: 23.02.2026

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.

Secondary language

• Language: Slovenian
• Keywords: modifikacija lesa, plantažni listavci, kompresijsko razmerje, modul lomne trdnosti, modul elastičnosti, razmerje med gostoto in lastnostmi

Projects

• Funder: The Ministry of Science, Technological Development and Innovation of the Republic of Serbia
• Project number: 451-03-65/2024-03/200169
• Name: The Ministry of Science, Technological Development and Innovation of the Republic of Serbia