Bond durability characterization of preservative treated wood and E-glass/phenolic composite interfaces

The objective of this study was to determine the effects of various wood preservative systems and treatment processes (pre- and post-treatment) on wood/FRP composite adhesive bond durability and shear strength. The effects of common wood preservative treatments on the durability of wood and E-glass/phenolic pultruded sheet interfaces and wood/wood interfaces was studied through a standard accelerated cyclic exposure test method. Pre-treatment of individual wood laminations with oil-borne (copper naphthanate, pentachlorophenol and creosote) and water-borne (CCA and CDDC) preservatives increased the delamination between the wood and FRP composite reinforcement with respect to untreated control samples. Post-treatments of wood/FRP composite laminated beams with the same preservative systems had more limited effects than pre-treatments on delamination. In most cases, for both pre and post treatment the wood/FRP delamination was beyond the limit allowed for wood-wood gluelines by the standard. Compatible preservative systems for use with E-glass/phenolic composite reinforcement in pre- and post-treatment applications, which are appropriate for the preservative/pressure treatment used by the wood-lamination industry, were identified. Preservative treatment recommendations were developed.