Water uptake of thermally modified Norway spruce

Žlahtič, Mojca (author), Thaler, Nejc (author), Humar, Miha (author)

Thermal modification of wood has been commercially available for almost twenty years but the complete mechanism of improved durability is still not completely understood. It is known that the temperature and duration of the modification influences the properties of the final products. There are several potential reasons for the increased durability of the modified wood. In recent research in particular, water exclusion efficiency has been identified as one of the key mechanisms. In order to elucidate this presumption, specimens made of Norway spruce heartwood were thermally modified at 6 different temperatures (160 °C, 180 °C, 190 °C, 200 °C, 210 °C and 230 °C) for three hours according to the Silvapro procedure. Control specimens were left unmodified. Three sets of tests were performed: (a) samples were soaked in water for 4 days and then positioned on load cells and allowed to dry until a constant mass was achieved; (b) short term water uptake was determined with a tensiometer and (c) wood-water interactions were verified using constant gravimetric moisture measurement during outdoor exposure. As expected, the degree of modification was reflected in the moisture content of the wood during testing. Short and medium term water uptakes correlated quite well with the performance of wood in outdoor applications. On the other hand, long term tensiometer measurements were not in line with either short term water uptake or outdoor measurements.

• Language: Croatian
• Keywords: Picea abies, merilna celica, tenziometer, termična modifikacija, navzem vode, terenska testiranja
• Work type: Not categorized
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2015
• Number of pages: Str. 273-279
• Numbering: Let. 66, št. 4
• PID: 20.500.12556/RUL-82446
• UDC: 630*813.13
• ISSN on article: 0012-6772
• DOI: 10.5552/drind.2015.1421
• COBISS.SI-ID: 2479241
• Publication date in RUL: 25.05.2016

Record is a part of a journal

• Title: Drvna industrija : Znanstveno stručni časopis za pitanja drvne tehnologije
• Shortened title: Drv. ind.
• Publisher: Šumarski fakultet Sveučilišta u Zagrebu, Hrvatsko šumarsko društvo, Croatiadrvo, d. d., Exportdrvo, p. o.
• ISSN: 0012-6772
• COBISS.SI-ID: 2858754

Secondary language

• Language: English
• Title: Upijanje vode toplinski modificirane norveške smreke

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P4-0015
• Name: Les in lignocelulozni kompoziti

• Funder: ARRS - Slovenian Research Agency
• Project number: L4-5517
• Name: Preprečevanje vlaženja lesa, kot merilo učinkovitosti zaščite lesa pred glivami razkrojevalkami