New aspects on the strength behaviour of thermally modified wood towards structural applications

Thermal modification is an environmental friendly technology to improve the dimensional stability and biological durability of wood. At present, the use of thermally modified wood (TMW) is limited to non-structural applications, e.g. cladding, decking. TMW gives lower mechanical strength due to loss in mass by thermal degradation of the wood material, and is more sensitive towards crack initiation and propagation. Nevertheless, there is a growing interest in using thermally modified timber for construction elements and previous results have shown that this potential exists. Therefore, the present project pursues the development of a multidisciplinary research in exploring the fundamentals of strength behaviour of TMW needed to expand its uses in the construction sector. Specifically, it will be studied the fracture characteristics, strain distribution around defects, creep, fatigue and long-term behaviour of mechanically loaded TMW to obtain reliable predictions of bending stiffness but also of its local variability and the effects of wood defects. By doing so, it is aimed to evaluate the possibility of developing a strength grading system of TMT, provide suggestions on its suitability for different structural uses, and give a feedback for adjustments of industrial production processes. It is foreseen that the project results will be disseminated to the scientific and industrial community, and to the stakeholders of the wood and construction sectors.