Influence of the treatment phase on the gluing performance of glued laminated timber

Glued laminated timber (glulam) is a wood-based product with frequent use in timber construction. Maritime pine (Pinus pinaster Ait.) is a species suitable for glulam production and is available with abundance in Portuguese forests. This study assessed the influence of the phase in which the preservative treatment is applied in the surface bonding performance. Several elements were produced considering different treatment scenarios: timber without treatment, timber treated before gluing, and timber treated after gluing. The bonding quality was tested by both shear strength and delamination tests, following the indications given in EN 14080 (2013). Glulam elements treated after gluing (TAG) presented less delamination when compared with the ones treated before gluing (TBG). However, TBG elements presented higher shear strength values than TAG elements. Despite the recorded differences, all the considered sets performed adequately both for delamination and shear strength tests.