The natural durability of wood refers to the resistance to attacks by wood-destroying organisms, e.g. fungi, insects and marine organisms. In this study the durability of thermally modified timber (TMT) was investigated. In field test (DIN EN 252, 1990) a variety of wood-dwelling and wood-destroying organisms occur simultaneously, while in lab test (EN DIN 113, 1996) idealized test conditions and the use of monocultures may lead to a different classification of the durability. The durability of TMT specimens was determined both in the lab test directly by the median fungal mass loss after a 16-week incubation period and in the field test by the durability factor of the samples, which were exposed for the moment 2.5 years. As a result an analog trend concerning all batches has been recognized in comparison of the two current tests. Within batches of lower treatment intensities the detected degradation was higher and deviations were greater compared to increased intensities. The smaller the median weight loss and the degradation rate of the specimens, the lower and thus better the durability classification. The process induced changes of the colour (L* b* variables from CIEL*a*b* system) showed strong correlation with the process evoked decrease in mass and consequently also with the classification of durability classes of the complete test set.
Keywords: colour, natural durability, thermally modified timber, outdoor exposure, quality control
Authors
Clauder L.
Wood Chemistry, Wood Physics and Chemical Engineering, Eberswalde University for Sustainable Development, Germany, Eberswalde
Pfriem A.
Wood Chemistry, Wood Physics and Chemical Engineering, Eberswalde University for Sustainable Development, Germany, Eberswalde
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