PSI - Issue 59

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Sviatoslav Homon et al. / Procedia Structural Integrity 59 (2024) 595–600 Sviatoslav Homon et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Modified samples, treated with the autoclave method, are environmentally friendly, water-resistant, and fire resistant building materials. Prisms were tested under axial compression in a press for short-term loading under a rigid testing regime (based on the plate displacement increment) in accordance with standard documents (ASTM D 143-14: 2014; EN 380: 2008; DSTU 3129: 2015). 3. Results and discussion The physical method of wood modification, specifically vacuum impregnation, allows for changes in several material properties, namely:

− provides reliable protection against micro- and macroorganisms; − eliminates the need for pre-treatment with antiseptic substances; − increases the fire resistance of wood; − environmentally friendly process; − improves the physical and mechanical properties of wood.

Autoclave impregnation technologies depend on several factors and tasks determined by the experiment (Peretyatko et al. (2019)), as they take into account key initial parameters such as moisture content, pressure, and impregnation method (polymer solutions, oils, etc.). Therefore, the process occurs in logical chains, such as:

− vacuum – pressure – vacuum; − pressure – pressure – vacuum; − vacuum – atmospheric pressure – vacuum; − pressure – vacuum; − autoclave-diffusion impregnation; − combined (hybrid) drying – impregnation.

The research used the “pressure - vacuum” method for selected birch, pine, and spruce samples. Key stages of this method (semi-confined absorption or the Laurie method) include introducing the impregnating liquid into the wood under excess pressure, draining the solution, and holding the wood under vacuum. The pressure-vacuum method is typical for impregnating material with oils, achieving deep penetration. The results of experimental studies on solid wood at standard moisture content are presented in Table 2, and for modified wood (average values for 3 samples) in Table 2.

Table 2. Results of experimental studies on solid wood at standard moisture content 12%. Group Wood species f c , 0,d , MPa 1 Pine 46.2 2 Pine 44.4 3 Pine 44.7 Average value Pine 45.1 4 Birch 45.8 5 Birch 47.1 6 Birch 46.1 Average value Birch 46.3 7 Spruce 41.9 8 Spruce 44.8 9 Spruce 43.5 Average value Spruce 43.4

The results of the studies on prism-twins of different wood species (pine, spruce, birch), modified with a composition of linseed oil and an accelerator, tar oil, containing turpentine and linseed oil, as well as boric acid,