The growing demand for renewable raw materials, climate change and the sustainability of the circular economy force manufacturers to explore the use of new and underutilized wood species in wood products. In addition, rising prices and environmental factors contribute to the search for new solutions. The most common wood species used in plywood production in the Nordic countries and the Baltic region is birch (Betula pendula). Previous studies have shown that aspen and alder plywood have lower bending strength than birch plywood, while having lower price and density. To use these species as an alternative to birch, densified veneers were utilised in plywood production. In recent years, investigations showed that densifying wood increases its strength properties, however, the real effect on bending strength considering amount of material used and thickness loss were not investigated properly. The aim of this study was to evaluate the effect of different veneer thicknesses, lay-up systems and veneer densification on the mechanical properties of veneer-based composite produced from low quality and underutilized wood species such as aspen (populus tremula) and black alder (alnus glutinosa). Effects on modulus of rupture (MOR), modulus of elasticity (MOE), adhesive consumption, screw withdrawal, and density were observed.
Keywords: veneer, densification, aspen, birch, black alder, plywood, bending strength
Authors
Tolgay Akkurt
Tallinn University of Technology, Estonia
Jaan Kers
Tallinn University of Technology, Estonia
Anti Rohumaa
South Eastern Finland University of Applied Sciences, Finland
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