The effect of an outdoor exposure on a content of extractives and compressive strength

Namen raziskave je bil preučiti vsebnost celokupnih fenolov ter organskega ogljika v izpirkih treh različnih lesov: domači kostanj (Castanea sativa Mill.), navadna bukev (Fagus sylvatica L.), navadna smreka (Picea abies L.) in navadna smreka zaščitena z baker-etanolaminskim pripravkom Silvanolin%. Prav tako nas je zanimala sprememba tlačne trdnosti vzorcev. Ti so bili izpostavljeni 3. razredu izpostavitve v obdobjih med 4 in 30 mesecev. Topni organski ogljik v izpirkih smo določili s TOC analizo, delež celokupnih fenolov pa z UV-VIS spektrofotometrijo. Meritve tlačne trdnosti smo opravili s strojem Zwick-Roell na zračno suhih vzorcih. Ugotovili smo, da se ob daljšem času izpostavitve delež ekstraktivov poveča, kar se odraža v večjem deležu topnega organskega ogljika in/ali celokupnih fenolov. Razlog za povečan delež ekstraktivov je predvsem biotska razgradnja lesa. Pri določanju tlačne trdnosti smo pri vseh lesnih vrstah ugotovili, da je ta obratno sorazmerna s časom izpostavitve vremenskim vplivom.The purpose of this thesis was to examine the total content of phenols and total organic carbon in the eluate of three different wood species: sweet chestnut (Castanea sativa Mill.), European beech (Fagus sylvatica L.), Norway spruce (Picea abies L.) and Norway spruce protected by a copper-ethanolamine preservative Silvanolin%. The research also explores the change of the compressive strength of the samples. They were exposed to third class exposure in periods between 4 and 30 months. Soluble organic carbon in the eluates was determined by TOC analysis, whereas the proportion of total phenols by UV-VIS spectrophotometry. Furthermore, measurements of compressive strength were performed with the machine Zwick-Roell on air-dried samples. The results show that longer exposure time increases the share of extractives, which is reflected in the greater proportion of soluble organic carbon and / or total phenols. The increased proportion of extractives is mainly caused by bio-degradation of wood. Finally, the study reveals that compressive strength in all wood species is inversely proportional to the time of exposure to weather conditions