Study of the mechanical behavior of glued laminated wood of Hevea brasiliensis bonded with polyurethane adhesive

Abstract

The aim of this work was to evaluate the properties of rubber wood (Hevea brasiliensis) for the production of structural pieces of glued laminated timber. Six trees with ages of approximately 12 years and diameter at breast height (DBH) greater than 25 cm were felled. Glued laminated timber beams were produced with three layers measuring 6.0 × 2.0 × 120.0 cm per beam, in a total of 6 beams, using the one-component polyurethane adhesive. The moisture, apparent density and porosity of the solid wood were determined. The modulus of elasticity (MOE), the modulus of rupture (MOR), shear strength (single and double line), delamination and visualization of the glue line were determined by means of photomicrographs of the laminated wood samples. The values of the analyzed properties were close to the species traditionally used for the production of beams of glued laminated wood, meeting the minimum requirements for this purpose according to the norms NBR 7190 and JAS 234 for MOR (30 MPa) and for single and double glue line shear strength (5.40 MPa) in the dry condition.