Русский
English
This paper presents an innovative two-stage physicochemical modification approach for softwood species, aimed at enhancing the operational reliability of glued laminated timber beams used in long-span building structures. In the first stage, bulk thermal modification (TM) is carried out in the exhaust gas atmosphere of a waste-heat boiler at 180–240 °C, resulting in reduced hygroscopicity, improved dimensional stability, and enhanced biological resistance. In the second stage, the surface layer of the thermally modified wood undergoes ultraviolet (UV) irradiation (wavelength: 253 nm; dose up to 7.4 kJ/m²) to restore hydrophilicity and improve adhesive bonding performance. Experimental results confirm that the contact angle of the surface decreases from 82° (TM only) to 8° at a UV dose of 7.4 kJ/m² – corresponding to a 90 % increase in wettability. Shear strength of the adhesive joint increases by 22.4 % compared to untreated thermally modified wood and approaches the level observed for joints made from untreated pine wood (deviation < 9 %). After two-stage modification, the mechanical performance of glued laminated beams – specifically, the modulus of rupture in static bending – reaches 58.3 ± 2.1 MPa, fully complying with the requirements of GOST 20850-2014 for glued laminated timber structures of strength class C24 and above. The proposed technology successfully combines the high moisture and biological resistance of thermally modified wood with reliable adhesive bonding-an essential requirement for load-bearing structural elements exposed to cyclic variations in temperature and humidity.
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3. Atilgan A., Burdurlu E., Atar M., Yasar S.S. Effect of the mechanical densification process in wood material on the surface adhesion strength of varnishes. BioResources. 2024. 19 (4). P. 7977 – 7989.
4. Pelit H., Koc E., Cakicier N. Adhesion strength and pendulum hardness of some coatings in wood heat-treated by different methods. BioResources. 2023. 18 (4). P. 7353 – 7366. DOI: 10.15376/biores.18.4.7353-7366
5. Yasar M., Altunok M. Production of sustainable low density composite insulation boards with vegetable fibre from forestry and agricultural wastes. Fırat University Journal of Engineering Science. 2023. 35 (2). P. 699 – 712. DOI: 10.35234/fumbd.1318101
6. Sauerbier P., Mayer A., Emmerich L., Militz H. Fire retardant treatment of wood – State of the art and future perspectives. In: Proceedings of the International Conference on Wood Science and Technology. Springer. 2020. P. 97 – 102. DOI: 10.1007/978-3-030-41235-7_14
7. Khasanshin R.R., Saerova K.V., Galyavetdinov N.R., Salimgareeva R.V., Mukhametzyanov Sh.R., Safin R.R. Application of low-temperature plasma treatment to improve mechanical properties of glued timber structures. Woodworking Industry. 2021. 4. P. 67 – 74.
8. Saerova K.V. High-frequency low-temperature plasma treatment of thermally modified wood filler. PhD Thesis. Kazan National Research Technological University (KNRTU). 2024. 143 p.
9. Prokopyev A.A., Salimgareeva R.V., Safin R.R. Investigation of acetylated wood properties. Woodworking Industry. 2023. 1. P. 86 – 91.
10. Yang T., Luo D., Wang L., Liu Y., Mei C. Improving fast-growing poplar wood with furfuryl alcohol and a hyperbranched polymer. Cellulose. 2024. 31. P. 6485 – 6499. DOI: 10.1007/s10570-024-05911-2
11. Frihart C., Brandon R., Ibach R., Hunt C., Gindl-Altmutter W. Comparative adhesive bonding of wood chemically modified with either acetic anhydride or butylene oxide. Forests. 2021. 12 (5). P. 546. DOI: 10.3390/f12050546
12. Saerova K., Safin R., Galyavetdinov N. High-frequency low-temperature plasma treatment of thermally modified wood filler and its effect on the properties of filled polymers. Fibre Chemistry. 2025. 56. P. 334 – 339. DOI: 10.1007/s10692-025-10582-x
13. Teischinger A., Avramidis S., Hansmann C., Mayrhofer A. Sawn timber steaming and drying. In: Niemz P., Teischinger A., Sandberg D. (eds) Springer Handbook of Wood Science and Technology. Springer Handbooks. Springer, Cham. 2023. DOI: 10.1007/978-3-030-81315-4_23
14. Kupryaniuk K., Oniszczuk T., Combrzyński M., Matwijczuk A., Pulka J. Physical and thermal modification of selected lignocellulosic raw materials. International Agrophysics. 2023. 37 (2). P. 141 – 149. DOI: 10.31545/intagr/161612
15. Bekhta P., Sedliačik J., Bekhta N. Effect of veneer-drying temperature on selected properties and formaldehyde emission of birch plywood. Polymers (Basel). 2020. 12 (3). P. 593. DOI: 10.3390/polym12030593
16. Wachter I., Štefko T., Rantuch P., Martinka J., Pastierová A. Effect of UV radiation on optical properties and hardness of transparent wood. Polymers (Basel). 2021. 13 (13). P. 2067. DOI: 10.3390/polym13132067
17] Cirule D., Kuka E., Andersone I. et al. Wood discoloration patterns depending on the light source. Heritage Science. 2022. 10. P. 158. DOI: 10.1186/s40494-022-00795-2
18. Saerova K.V., Safin R.R., Timoshina Yu.A. Effect of high-frequency low-temperature plasma treatment on the chemical composition of thermally modified wood filler. Systems. Methods. Technologies. 2024. 3 (63). P. 173 – 179.
19. Mothilal T., Ragothaman G., Joseph Manuel D., Socrates S., Mathavan S. Analysis on mechanical properties of wood plastic composite. AIP Conference Proceedings. 2020. 2283 (1). P. 020037. DOI: 10.1063/5.0024893
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Isaeva Zh.M., Saerova K.V., Safin R.R., Sambetbayeva A.K. Bulk thermostabilization and surface UV activation as a wood modification method for glued beams in long-span structures. Construction Materials and Products. 2026. 9 (1). 10. https://doi.org/10.58224/2618-7183-2026-9-1-10