Bonding quality assessment of cross-layered Maritime pine elements glued with one-component polyurethane adhesive

• Published in: Construction & building materials 2019-06, Vol.211, p.571-582
• Main Authors: Santos, Pedro, Correia, João R., Godinho, Luís, Dias, A.M.P.G., Dias, André
• Format: Article
• Language: English
• Subjects: Analysis; Australian blackwood; Bonding quality; Cross-laminated timber; Delamination; Laminates; Maritime pine; Mechanical properties; Polyurethane adhesives; Shear strength; Soil shear strength
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.03.064

•Increasing the bonding pressure enhances delamination and wood failure percentage.•Pre-treatment with primer enhanced results for all the bonding quality parameters.•Layer thickness and adhesive spread rate showed few influence on results.•Shear strength requirements of EN 16351 were always fulfilled.•Delamination requirements of EN 16351 were not always fulfilled. This paper presents an experimental study about the bonding quality of Maritime pine (Pinus pinaster Ait.) cross-layered wood elements glued with one-component polyurethane adhesive. The experiments comprised shear and delamination tests according to standard EN 16351 focusing on the influence of the following parameters: bonding pressure, adhesive spread rate, pre-treatment with primer and layer thickness. The results obtained show that increasing bonding pressure increases significantly the wood failure percentage after delamination or shear tests, while the delamination and the shear strength are not significantly affected. Moreover, it was found that the use of primer enhances significantly the bonding quality; nevertheless, EN 16351 requirements are fulfilled even for the lower bonding pressure and adhesive spread rate recommended by the manufacturer of the adhesive used in the experiments. The layer thickness, for the tested range, had no influence on the delamination and shear results and limited one on the wood failure percentage after shear or delamination tests. No relevant influence was found for the adhesive spread rate. In the experiments the combination of gluing Maritime pine with Australian blackwood (Acacia melanoxylon R.Br.) was also investigated and, for this combination, the standard requirements were successfully fulfilled.