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Wood modification is an appropriate way of improving the natural durability and dimensional stability of wood without the use of biocides. Different thermal and chemical wood modification processes are available for this purpose, very differently affecting the structural integrity of wood. In this study, thermally modified, melamine resin treated, acetylated, furfurylated, and mDMDHEU treated wood underwent abrasion tests according to two different methods representing different loads in practice. The Taber Abraser method caused crosswise cutting into the wood surface, while the Shaker method challenged mainly the specimen edges with dynamic loads. Abrasion resistance of wood was affected by all types of cell wall modification, but the effects were strongly dependent on the type of modification and the applied load type. For characterising the suitability of wooden materials with respect to wear resistance under outdoor conditions, it is recommended to apply a set of methods rather than a single test procedure to fully reflect the loads occurring in practice.

Wood modification is an appropriate way of improving the natural durability and dimensional stability of wood without the use of biocides. Different thermal and chemical wood modification processes are available for this purpose, very differently affecting the structural integrity of wood. In this study, thermally modified, melamine resin treated, acetylated, furfurylated, and mDMDHEU treated wood underwent abrasion tests according to two different methods representing different loads in practice. The Taber Abraser method caused crosswise cutting into the wood surface, while the Shaker method challenged mainly the specimen edges with dynamic loads. Abrasion resistance of wood was affected by all types of cell wall modification, but the effects were strongly dependent on the type of modification and the applied load type. For characterising the suitability of wooden materials with respect to wear resistance under outdoor conditions, it is recommended to apply a set of methods rather than a single test procedure to fully reflect the loads occurring in practice., Modifikacija drva prikladan je način poboljšanja njegove prirodne trajnosti i dimenzijske stabilnosti bez upotrebe biocida. Za tu namjenu dostupni su različiti postupci toplinske i kemijske modifikacije, ali oni vrlo različito utječu na strukturni integritet drva. U ovom su istraživanju toplinski modificirano drvo, drvo modificirano melaminskom smolom, acetilirano i furfurilirano drvo te drvo modificirano mDMDHEU-om podvrgnuti ispitivanju otpornosti na habanje, i to primjenom dviju različitih metoda koje u praksi rezultiraju različitim opterećenjima. Metoda Taber abraser uzrokovala je poprečno habanje površine drva, a metoda Shaker dinamičkim je opterećenjima uglavnom prouzročila habanje rubova uzoraka. Na otpornost drva na habanje utjecale su sve vrste modifikacija drvnih stanica, ali učinci su izrazito ovisili o vrsti modifikacije i vrsti opterećenja. Za karakterizaciju prikladnosti drvnih materijala s obzirom na otpornost na habanje u vanjskim uvjetima preporučuje se primijeniti skup metoda, što je bolje od primjene samo jedne vrste ispitivanja kako bi se u potpunosti simulirala opterećenja koja se pojavljuju u praksi.

Eucalyptus nitens is a fast growing plantation species that has a good acclimation in Spain and Chile. At the moment it is mainly used for pulp and paper production, but there is a growing market for solid wood products made from this species. Thermal modification offers a good alternative to produce high quality material to manufacture products with high added value. This study used unmodified and thermally modified E. nitens wood from Spanish and Chilean plantations to elaborate external decking and examine if it complies with the necessary properties to be a competitive product. A process similar to ThermoWood® was applied at the following temperatures: 185 °C, 200 °C and 215 °C. For each modification and for an unmodified specimen mass loss, volumetric swelling, anti-swelling efficiency (ASE) and equilibrium moisture content (EMC) were determined. Brinell hardness, dynamic hardness, screw and nail withdrawal resistance, and abrasion resistance according to the Shaker method and the Taber Abraser method were also determined. According to this study, thermally modified E. nitens from both countries showed high potential to be used as decking material, particularly when modified at 200 °C., Eukaliptus nitens brzo je rastuća plantažna vrsta koja se dobro prilagodila klimi u Španjolskoj i Čileu. Trenutačno se uglavnom iskorištava za proizvodnju celuloze i papira, ali sve je veće tržište proizvoda izrađenih od masivnog drva te vrste. Toplinskom modifikacijom dobiva sa dobra alternativa za proizvodnju visokokvalitetnih proizvoda s visokom dodanom vrijednošću. U ovom je istraživanju kao materijal za vanjske podne obloge upotrijebljeno nemodificirano i toplinski modificirano drvo E. nitens sa španjolskih i čileanskih plantaža te je ispitana njegova sukladnost sa svojstvima potrebnima za postizanje konkurentnosti. Primijenjen je postupak sličan procesu ThermoWood®, i to pri temperaturama 185, 200 i 215 °C. Za svaki modificirani i nemodificirani uzorak određen je gubitak mase, volumno bubrenje, učinak smanjenja bubrenja (ASE) i ravnotežni sadržaj vode (EMC). Određene su i tvrdoća prema Brinellu, dinamička tvrdoća, otpornost na izvlačenje vijaka i čavala te otpornost na habanje prema metodama Shaker i Taber abraser. Na temelju ovog istraživanja može se zaključiti da su toplinski modificirani uzorci drva E. nitens iz obje zemlje pokazali visok potencijal za uporabu u obliku vanjskih podnih obloga, posebice ako su modificirani pri 200 °C.

Various biotic and abiotic agents affect the performance of wood products. Chemicals, thermal energy, radiation, as well as different organisms have the potential to alter the optical, haptic and functional performance of wood. These effects come along with a change of structural integrity of wood, which in turn affects its strength properties. Therefore, a test was developed to quantify the structural integrity of wood in terms of its Resistance to Impact Milling (RIM). In a High-Energy Multiple Impact (HEMI) – test, steel balls were used in a heavy vibratory mill for crushing wood samples. Thousands of single events were captured by analyzing the fragments. Based on the degree of integrity and the percentage of fine fragments (< 1mm), an indicator has been defined to detect structural changes on cell wall level with high sensitivity. The aim of this study was to investigate the variation of structural integrity within and between ten different wood species in comparison with some strength properties according to standardized test protocols and in dependence of wood density. HEMI-tests, bending tests, and impact bending tests were performed with matched specimens. Wood density turned out to have only a subsidiary effect on structural integrity, but is dominanting standard strength properties. Thus, RIM was found to be only slightly correlated with the impact bending strength (IBS) and bending strength (MOR). On the other hand, the method shows clear insensitivity to natural variation in anatomy of wood., Na svojstva proizvoda od drva utječu brojni biotički i abiotički činitelji. Kemikalije, toplinska energija, zračenja i različiti organizmi mogu promijeniti optička, haptička i funkcionalna svojstva drva. Te učinke prate i promjene strukturnog integriteta drva, što pak utječe na njegovu čvrstoću. Stoga je razvijen test za kvantificiranje strukturnog integriteta drva s obzirom na njegovu otpornost na udarce (RIM). Za provedbu testa višestrukih udaraca visoke energije (HEMI test) upotrijebljene su čelične kuglice u teškome vibracijskome mlinu za drobljenje uzoraka drva. Analizom fragmentiranog drva obuhvaćeno je više tisuća pojedinačnih događaja. Na temelju stupnja integriteta i postotka sitnih čestica (< 1 mm) defi niran je pokazatelj vrlo visoke osjetljivosti koji otkriva strukturne promjene na razini stanične stijenke. Ova je studija usmjerena na istraživanje varijacija strukturnog integriteta unutar i između deset različitih vrsta drva u usporedbi s odabranim svojstvima čvrstoće prema standardiziranim ispitnim testovima te u ovisnosti o gustoći drva. HEMI testovi, testovi savijanja i testovi ispitivanja žilavosti provedeni su na odgovarajućim uzorcima. Pokazalo se da gustoća drva ima samo sekundarni utjecaj na strukturni integritet, a da dominantnu ulogu imaju standardna svojstva čvrstoće. Rezultati su pokazali da je RIM slabo povezan sa žilavošću materijala (IBS) i čvrstoćom na savijanje (MOR). No predstavljeni je pokazatelj nedvojbeno neosjetljiv na prirodnevarijacije u građi drva.

Thermally modified timber (TMT) is increasingly offered in Europe as an alternative to preservative treated timber. TMT durability, infield tests as well as its moisture sorption behaviour in facade application was determined so as to consider its suitability for outdoor use. Additionally, abrasion and crack-formation of TMT deckings were examined and the optical appearance of a TMT facade was evaluated after 5 years of service. After 7.5 years exposure in ground contact, the various TMT materials tested were classed as "slightly durable" to "not durable" whereas the classification in above ground exposure was "very durable" to "moderately, durable", which was in line with the reduced moisture sorption of TMT in weathered application. Moreover, the TMT-decking showed less abrasion and crack-formation compared to references, though the TMT facade revealed considerable discoloration by weathering. Hence, the suitability of TMT for above ground use is suggested, but a surface treatment is obligatory if discoloration is objectionable.