Shear Performance of Adhesive Bonding of Cross-Laminated Bamboo

Abstract

Tests were conducted of the bonding shear strength of different bamboo configurations in terms of grain direction, adhesive, and clamping pressure. The bonding shear tests were carried out with two basic configurations: glued together with the grain in the same direction, and cross-laminated. Five different adhesives were used: emulsion polymer isocyanate (EPI), polyurethane (PUR), melamine-urea-formaldehyde (MUF), hybrid polymer adhesive (HPA), and polyvinyl acetate (PVA). To assess the optimum value, specimens were prepared with three clamping pressures. According to the test results, the most suitable adhesive for glued laminated bamboo surface is MUF; EPI is not effective for bonding laminated bamboo elements, and PVA performs the best for scrimber produced with cross-laminated bamboo. The results also showed that end grain specimens had the highest bonding shear strengths among the four configurations, and that, in accordance with the properties of raw bamboo, cross-laminated types exhibited similar mechanical characteristics in both directions. It can be concluded that the testing method used for cross laminated timber is also suitable for assessing the shear strength of adhesive bonds for cross-laminated bamboo.