Wood is an important material used for railway sleepers. Because railway sleepers are exposed to moisture and various organisms (fungi and insects) we have to adequately protect them. For impregnation of railway sleepers in Europe creosote oil is predominately applied. However, according to the European Biocidal Guidelines, creosote oil will only be allowed for wood protection until a new adequate preservative is developed. In this work, prepared in the framework of the ERASMUS student exchange at the University Georg-August Göttingen, Germany, we tested three newly developed copper-ethanolamine biocidal products with working names 181, 169 and Impralit NN. We used them to protect the wood of beech (Fagus sylvatica), oak (Quercus sp.) and Scots pine (Pinus sylvestris) and tested the uptake of the preservatives, resistance of impregnated wood to fungal decomposition, bending strength of the impregnated wood and the influence of the selected preservatives on metal corrosion. With accelerated aging we also evaluated the changes in impregnated wood. We found that the copper-based preservative 181 proved to be sufficiently effective against the fungi Coniophora puteana and Trametes versicolor, and that the impregnation did not significantly affect relevant mechanical properties. Preservatives also did not significantly affect metal corrosion. During accelerated aging fewer cracks occurred in the wood samples impregnated with the biocide of lower concentration. In general, all three preservatives proved to have at least some appropriate properties, but it will be necessary to do further research before the studied biocides could replace the creosote oil.
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