Recycling of pentachlorophenol-treated southern pine utility poles. Part II: Mechanical and delamination properties of laminated beams.

摘要

Reusing decommissioned utility poles and other preservative-treated wood reduces the total amount of preservatives in the environment and the need to fall the trees in the forest, offering economic and ecological advantages. In a previous study, the pentachlorophenol (penta) retention and mechanical properties of decommissioned penta-treated southern pine utility poles and pole sections were investigated. The current study evaluated the mechanical and delamination properties of laminated beams made of penta-treated utility pole wood. A total of 45 laminated beams and 15 solid-sawn beams were fabricated from decommissioned penta-treated utility pole wood and untreated southern pine virgin wood. Three composition schemes and two surface preparation methods were investigated for their effects on penta retention, bending, glue-line shear, and delamination properties of the laminated beams. Penta-treated utility pole wood absorbed more penta than virgin wood during retreatment. The bending strength of the laminated beams met American National Standard Institute Standard 05.3. However, percent delamination of the laminated beams failed to meet the standard requirement set by ASTM Standard D2559, and thus, penta-treated utility pole wood beams consolidated by resorcinol phenol formaldehyde resin cannot be used in exterior exposure conditions.