Natural durability, extractive ratio and selected mechanical properties of beech wood damaged by insects

Les je pomemben gradben materialv te namene se uporablja že tisočletja. Je naravno obnovljiva surovina, kar je ena njegovih glavnih prednosti. Ima več življenjskih ciklovodslužen les lahko ponovno uporabimo ali recikliramo v nove izdelke. V kolikor želimo takemu lesu povečati dodano vrednost, je dobro poznati njegove relevantne lastnosti (odpornost, poškodbe, mehanske lastnosti, itd.). Da bi osvetlili te lastnosti, smo iz stare bukovine izdelali vzorce in jih izpostavili 5 glivam razkrojevalkam lesa (Hypoxylon fragiforme, Pleurotus ostreatus, Trametes versicolor, Gloeophyllum trabeum in Antrodia vaillantii). Gravimetrično smo določili izgubo mase, mehanske lastnosti pa z metodo upogibne in tlačne trdnosti. Določili smo delež izpranih ekstraktivov. Rezultati kažejo, da je naravna odpornost stare bukovine primerljivo slabša kot odpornost sveže posekane bukovine. Žal pa so preiskovane mehanske lastnosti starega bukovega lesa bistveno slabše. Glavni vzroki za poslabšanje so izletne odprtine insektov in dejstvo, da je bil les že delno strohnjen. Uporabnost starega odsluženega bukovega lesa dodatno poslabšuje dejstvo, da star les vpija bistveno več vode kot svež.Wood is an important building material used for construction purposes for thousands of years. One of the main advantages of wood is that it is a naturally renewable raw material. Wood has more life cyclesused wood can be reused or recycled into new products. If we want a disused timber to raise the added value we have to be familiar with its relevant properties (resistance, damages, mechanical properties, etc.) To shed light on these properties, old beech samples were prepared and subjected to 5 species of wood decay fungi (Hypoxylon fragiforme, Pleurotus ostreatus, Trametes versicolor, Gloeophyllum trabeum, Antrodia vaillantii). The weight loss was defined gravimetriclymechanical properties by a method of flexural and compressive strength. The proportion of washed extractives was determined. The results show that the natural resistance of the old beech wood is worse compared to the resistance of freshly harvested beech wood. Unfortunately, the mechanical properties of the investigated old beech wood are much worse. The main causes of deterioration are the exit openings made by insects, and the fact that the timber is already partially decomposed. Use of old obsolete beech wood is further aggravated by the fact that the old wood absorbs significantly more water than fresh wood