Decay resistance against wood decay fungi and mechanical properties of old wood from hayrack

Podjetje M SORA je v bližini Žirov podrlo dotrajan lesen kozolec v Sedejevi dolini v vasi Opale. Iz pridobljenega lesa razvija in izdeluje nova lesena okna. Za namen raziskave smo iz starega lesa kozolca odvzeli okvirno 1 m dolge vzorce tramov, leg in špirovcev. Večina odvzetih vzorcev je bila iz smrekovega lesa, en vzorec pa iz lesa češnje. Iz večjih vzorcev smo pripravili vzorce za testiranje odpornosti proti lesnim glivam po standardu (EN 113) in vzorce za testiranje mehanskih lastnosti. Pri mehanskih testiranjih smo določali upogibno in tlačno trdnost. Določili smo gostoto lesa, izgubo mase, vlažnost vzorcev po izpostavitvi glivam, upogibni elastični modul, tlačno trdnost in upogibno trdnost. Rezultati odpornosti lesna na glive bele in rjave trohnobe so pokazali da je izguba mase vzorcev izdelanih iz starega lesa iz kozolca primerljiva z izgubo mase kontrolnih vzorcev izdelanih iz sveže posekane smrekovine. Do podobnih ugotovitev smo prišli tudi pri mehanskih testih. Glede na dobljene rezultate naše naloge lahko zaključimo, da ima star les iz kozolca velik potencial za ponovno uporabo.M SORA has demolished an old wooden hayrack in the Sedej valley in Opale village near Žiri. From the obtained wood, the company develop and manufactures new wooden windows. For the research purposes, approximately 1 m long beams, rails and rafters were used. Most of the samples taken were made of spruce wood, and one was made of cherry wood. Larger samples were prepared for the testing of durability to wood decay fungi according to the standard (EN 113) procedure and samples for testing the mechanical properties. Three-point bending test and compressive strength tests were performed. In the research, the density of the wood, the mass loss, the moisture content of the specimens after exposure to fungi, were determined. Mass loss after exposition to white and brown rot decay fungi showed that the mass loss of samples made from old used wood was comparable to the mass loss of control samples made from fresh sawn spruce. Similar findings were obtained at mechanical tests. Based on the results of our work, we can conclude that old used wood has great potential for reuse in different applications