Search

Copper based wood preservatives are among the most important wood preservatives for heavy-duty applications. Wood treated with copper-based preservatives performs excellently if applied according to preservative specifications. If used improperly, premature failures can appear. In order to elucidate the properties of copper treated wood in use, utility poles and posts treated with copper-based preservatives were investigated. Poles were cut into smaller specimens, and copper and chromium penetration, retention, mechanical properties, extractive content, short-term water uptake and fungicidal properties were then determined. The results clearly showed that wood retains its properties if treated with sufficient amounts of copper-based wood preservatives. Insufficient amounts of preservatives applied result in premature failures of wood commodities. Regardless of the type of wood preservative used, the central part of spruce wood poles and piles is the weakest point, where the majority of the failures occurs. [ABSTRACT FROM AUTHOR]

Sweet chestnut ( Castanea sativa ) heartwood is one of the most durable European commercial wood species. Various aspects that could potentially influence the durability were studied in the present research: presence of extractives, ring width and weathering. The properties of wood that had been in outdoor use for 35 years were also examined. The results indicate that ring width and weathering (outdoor use) did not influence the durability. None of the fungi used were able to degrade sweet chestnut heartwood in a modified EN 113 experiment. After extraction with methanol or water, specimens lost between 11% and 15% of total mass by leaching of extractives. However, extraction only slightly decreased the durability of the leached wood. This indicates that other components (in addition to water and methanol soluble extractives) could be responsible for durability. Furthermore, analysis of 35-year-old wood showed that not all relevant properties of the old sweet chestnut wood deteriorated within the mentioned time frame. This proves that old sweet chestnut hardwood can potentially be reused for a variety of applications. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to investigate differences in the mechanical and fungicidal properties of three different wood species (English oak (Quercus sp.), common beech (Fagus sylvatica) and Norway spruce (Picea abies)) that had been in indoor use for several decades, compared to control specimens of freshly cut timber. The collected material was cut into smaller samples prior to further analysis. Extractive content, mechanical, fungicidal and sorption properties were determined according to standard procedures. The obtained results showed that the mechanical properties of oak wood do not deteriorate over the investigated time frame. On the other hand, the resistance of oak wood against fungi decreases over time. The reason for this is yet to be confirmed; it may be due to degradation of secondary metabolites. Similar results have been reported for spruce wood. There were no statistically significant differences in the mechanical properties of old and new spruce wood. In contrast to oak wood, there were also no significant differences in fungicidal properties, bearing in mind that spruce wood has lower durability than oak wood. Aging of beech wood resulted in a considerable decrease in the tested mechanical properties but showed no significant differences in fungicidal properties. Old beech wood specimens were moderately deteriorated by insects and fungi, which was the reason for the loss of bending and compressive strength. Our results confirm that most of the relevant properties do not deteriorate with time and that wood can be reused for a variety of other applications even after decades in service. [Copyright &y& Elsevier]

Thermal modification is the most important commercial modification procedure. Thermally modified (TM) wood has improved durability, but its performance does not meet expectations predominately under moist conditions. To reduce water uptake of TM wood, Norway spruce specimens were treated with suspensions of a natural wax by dipping impregnation (DipI) or by vacuum-pressure impregnation (VPI). Wax-treated specimens were subsequently TM at 185, 200, 215, and 230°C. Control specimens were heated up to 100°C only. Contact angle (CA), short-term and long-term water uptake, bending strength, and performance against wood decay fungi of the resulting material were determined. The results show that a combination of wax treatment and thermal modification have a synergistic effect that considerably improves hydrophobicity, reduces liquid water uptake, slows down water vapor uptake, and improves the resistance against fungal decay of the treated material. [ABSTRACT FROM AUTHOR]