Effects of grading of veneers on properties of LVL made from Schizolobium amazonicum Huber ex. Ducke

Abstract

The work aimed at evaluating the influence of pre-classification of veneer made from parica (Schizolobium amazonicum Huber ex. Ducke) plantation trees on Laminated Veneer Lumber (LVL) properties. This species is native to the Amazonian and is fast growing with low density. For LVL production, veneers were separated into four classes according to the density or dynamic modulus of elasticity. LVL was produced considering three different strategies of assembly—random veneers assembly; assembly using veneers with greater EMd placed at the surface layer with gradual reduction up to the center of the panels; assembly using veneers with greater density placed at the surface layer and gradual reduction into the center of the panels. The following mechanical and physical properties were then evaluated: static bending modulus of elasticity (EM), modulus of rupture (fM), compression strength parallel to grain (fc0), shear strength parallel to glue-line (fv0), shear strength perpendicular to glue-line (fv90), water absorption and thickness swelling for 2 and 24 h of water immersion. Physical properties of LVL were not found to be influenced by different pre-classification strategies, while for mechanical properties only bending strength at flatwise position was influenced by pre-classifying veneers.