The effects of wood species, load direction, and adhesives on bending properties of laminated veneer lumber

Abstract

In this study, the bending strength and stiffness of laminated veneer lumber (LVL) produced from beech (Fagus orientalis L.), poplar (Populus x euramericana I-214), and eucalyptus (Eucalyptus grandis W. Hill ex Maiden) wood using urea formaldehyde (UF), melamine urea formaldehyde (MUF), and phenol formaldehyde (PF) adhesives were determined. The tests were conducted in the flatwise and edgewise directions. The modulus of rupture (MOR), modulus of elasticity (MOE), specific modulus of rupture (SMOR), and specific modulus of elasticity (SMOE) were calculated. Variance analysis of the bending properties indicated that the effects of the species of tree, the direction of the load, and the type of adhesive were statistically significant. However, according to variance analysis of the SMOR, the effects of the type of adhesive were not significant. The results showed that the type of adhesive did not influence the bending properties of laminated veneer lumber. It can be stated that the differences among groups were due to differences in their densities. The direction of the load and the species of the tree had significant effects on the bending properties.