Study of the mechanical properties of glued laminated timber (glulam) with treated Hevea brasiliensis and epoxy adhesive

The search for sustainable alternative sources of materials for use as structural elements in civil construction has been gaining prominence in recent years. Glued laminated timber (glulam) is an environmentally friendly option aimed at replacing traditional steel and reinforced concrete structures. However, challenges in the production of these ecological composite materials are known, such as the choice of adhesive to join the wood lamellas, and also related to the biodeterioration of the wood, a situation in which the structural reliability of the building can be compromised. The use of preservative solutions is an alternative that mitigates this problem and ensures greater durability of the material. The objective of this work was to evaluate the mechanical properties of glulam beams produced with rubberwood treated with chromated copper borate (CCB), chromated copper arsenate (CCA) and pyrethroid preservatives using epoxy as an adhesive, a type of formaldehyde-free adhesive. The glulam beams were produced with 3 lamellas measuring 60 × 20 × 1200 mm, differentiated by the presence or absence of preservative treatment. Rubberwood had an apparent density of 0.528 g.cm-3, being classified as low to medium density, therefore ideal for the production of glulam parts. The preservative treatments with CCA and CCB significantly reduced the evaluated mechanical properties, for example, the compressive strength parallel to the fibers was reduced from 49.27 MPa to 43.86 MPa for the glulam beams without preservative and treated with CCA, respectively. However, pyrethroid treatment did not affect the mechanical strength of the beams under study.