Lastnosti lesa po 7 letih izpostavitve na prostem

Jelšnik, Jure (author), Humar, Miha (mentor), Kržišnik, Davor (comentor)

Magistrsko delo obravnava lastnosti lesa po sedmih letih izpostavitve na prostem na terenskem polju Oddelka za lesarstvo. Testirali smo lesene vzorce smrekovine, ki je bila zaščitena z dvema tipoma bakrovih pripravkov (CCB in CuE pripravek) dveh različnih koncentracij (wCu = 0.25 % in 0.125 %). Les je bil izpostavljen v 3. in 4. razredu uporabe. Za primerjavo smo testirali kontrolne vzorce, ki niso bili izpostavljeni zunanjim dejavnikom. Cilji naloge so bili testirati les po sedmih letih izpostavitve na prostem ter izmeriti vsebnost bakra v lesu, določiti mehanske lastnosti lesa in ovrednotiti stopnjo razkrojenosti z mikroskopsko analizo. Rezultati so pokazali, da se je del bakrovih učinkovin spral iz lesa. Najintenzivnejše izpiranje smo opazili pri lesu impregniranem z zaščitnimi sredstvi z nizkimi koncentracijami v stiku z zemljo. Pri lesu izpostavljenim v tretjem razredu uporabe, je bilo izpiranje manj opazno. Tekom izpostavitve je les razpokal. Visoke koncentracije bakrovih učinkovin do določene mere preprečujejo pojav razpok. Mehanske lastnosti lesa izpostavljenega v tretjem razredu so bile boljše kot tistega v četrtem razredu uporabe. Les zaščiten s CCB in izpostavljen v četrtem razredu uporabe je razpokal, pri nižjih koncentracijah se je pojavila obarvanost, medtem ko so se pri s CuE zaščitenem lesu pojavili močan razkroj, zaznali smo spremembe barve in pri nekaj podzemnih delih vzorcev je prišlo do propada.

• Language: Slovenian
• Keywords: naravno staran les, zaščita lesa, CuE, CCB, mehanske lastnosti, gostota, pH
• Work type: Master's thesis/paper
• Organization: BF - Biotechnical Faculty
• Year: 2022
• PID: 20.500.12556/RUL-140877
• Publication date in RUL: 21.09.2022

Secondary language

• Language: English
• Title: Properties of wood after 7 years of outdoor exposure

Abstract

This Master's thesis deals with the wood properties after 7 years of outdoor weathering at the field test site of the Department of Wood Science and Technology. Spruce wood samples protected with two types of copper substances (CCB and CuE) in two different concentrations (wCu = 0.25 % and 0.125 %) were tested. The wood was exposed to the 3rd and 4th use class (UC). For comparison, control samples that were not exposed to the outside were also tested. The aim of the work was to test the wood samples after 7 years of exposure to weathering and to measure the copper concentration in the wood samples. Other objectives were to determine the mechanical properties of the wood samples and to classify the degree of decay by microscopic analysis. The results show that some of the copper substances were no longer present in the samples due to leaching. The strongest leaching was observed in wood impregnated with preservatives in low concentrations. These samples were also in contact with the soil. Wood samples that were subject to the 3rd UC were less affected by leaching. Cracks and splits were observed in the samples. High concentrations of copper substances reduce the likelihood of cracking and splitting to some extent. The mechanical properties of 3rd UC wood were better than those of 4th UC wood. Wood protected with CCB, subject to 4th UC, cracked and discolouration was observed at lower concentrations. On the other hand, severe decay was observed in the wood samples protected with CuE, as well as a change in colour and complete decay in some parts of the samples that were underground.

• Keywords: natural aged wood, wood protection, CuE, CCB, mechanical properties, density, pH