Determination of some physical and mechanical properties of laminated veneer lumber impregnated with boron compounds

The aim of this study was to determine the effects of Tanalith-C 3310 (T-C 3310), borax (Bo), boric acid (Ba), borax + boric acid (Bo + Ba), and diammonium phosphate (D) impregnations for some physical and mechanical properties of laminated veneer lumber (LVL). The veneers used for the LVL samples (based on BS EN 204) were cut from Scots pine (Pinus sylvestris L.), oriental beech (Fagus orientalis L.), and poplar (Populus nigra). They were impregnated with full-cell method according to ASTM-D 1413 standards and bonded with phenol formaldehyde (PF) and melamine formaldehyde (MF) adhesives. The following parameters have been tested: density, compression strength, bending strength, modulus of elasticity (MOE) in bending, and shear strength tests. Test results obtained from this study showed that impregnation with Boric acid and Tanalith-C 3310 (based acidic characteristic) affected the strength of LVL negatively, when the wood material is impregnated with acidic impregnations and bonded with PF, which is an alkali, the glue-line becomes more elastic, the bonding strength of adhesive weakens. Boric acid and Tanalith-C 3310 impregnations could not be recommended for LVL elements exposed to bending or shear strength. © 2007 Wiley Periodicals, Inc