Abstract
To prevent the degradation of structural glued laminated timbers (glulams) exposed to outdoor conditions, we investigated the reinforcement of those surfaces with poly vinyl alcohol fiber sheets (PVA-S). First, we studied the bonding of PVA-S on a wood surface with epoxy resin adhesive, including an examination of compatibility among wood preservatives (ACQ, AAC, NZN, NCU, CUAZ2), PVA-S and adhesive resin. Next, we studied the waterproof properties of PVA-S, the decrease of dimension changes and prevention of cracks or delaminations in reinforced glulam. We also investigated the influence of PVA-S reinforcement on the distribution of glulam moisture content via an outdoor exposure test. High bonding durability was obtained for wood-PVA-S adhesion, regardless of the pressing method, and the adhesion of preservatives-treated wood and PVA-S provided adequate bonding durability. Water did not penetrate below the surface of glulams with PVA-S lamination. Reinforcement with PVA-S decreased dimension changes of glulams and prevented the occurrence of delaminations or cracks during cyclic wet-dry treatment. PVA-S reinforcement prevented an increase of moisture content in glulams exposed to outdoor conditions.
