Crack propagation in biodegraded wood
INRA, Université Bordeaux 1, CNRS, UMR US2B, Bâtiment A11, 351, Cours de la Libération,
2 Université Bordeaux 1, INRA, CNRS, UMR US2B, Bâtiment A11, 351, Cours de la Libération, 33405 Talence Cedex, France
* Corresponding author:
Accepted: 3 February 2010
• Fungal attack in wood involves severe mechanical losses, even in the early stages, due to depolymerisation of polysaccharides. The safety of building components could therefore be affected. It is believed that fracture properties could be much more sensitive to decay than conventionally measured properties, such as weight loss.
• In this study, we propose the application of a fracture mechanics test, which measures the fracture toughness, KIC, during the biodegradation process. Two softwoods commonly used in construction, maritime pine and Douglas fir, were inoculated with Poria placenta. Samples were removed twice a week to determine the evolution of the decrease in their mechanical properties.
• Toughness was initially greater for maritime pine, but a significant decrease of this property was observed during decay progression, while KIC remained more stable for Douglas fir. For maritime pine there was a loss of 52% of KIC, after 6 weeks of degradation. This species appears to be less durable even with respect to weight loss, which is less sensitive to decay than toughness.
• This is a promising test for bio-damage quantification; however, due to the wood heterogeneity, measurement of the true impact of biodegradation is still difficult.
Key words: decay / Douglas fir / fracture / maritime pine
© INRA, EDP Sciences, 2010