Mechanical performance of nail-laminated posts manufactured from reclaimed chromated copper arsenate-treated decking lumber

This study determined the mechanical properties of nail-laminated (nail-lam) posts manufactured from reclaimed chromated copper arsenate (CCA)-treated decking lumber. Though CCA-treated lumber is no longer accepted for use in residential applications, it is permitted in agricultural and industrial applications where health and environmental impacts are deemed to be minimal. This project focused on the reuse potential of this lumber for fabricating structural nail-lam members commonly used in agricultural post frame utility buildings. Significant amounts of waste CCA-treated lumber are generated by people replacing decks. Currently, this lumber is mostly landfilled as disposal waste. Finding other uses for this discarded material could reduce the waste burden of decking removed from service each year. For this study, 15-yearold decking material slated for removal and composed of nominal 2 by 6 CCA-treated Southern yellow pine (SYP; Pinus spp.) lumber was carefully reclaimed for structural post member fabrications. Similar structural nail-lam posts were fabricated from new, micronized copper azole-treated SYP lumber for comparative test purposes. Three experimental treatments were evaluated to examine mechanical performance in terms of bending strength, flexural rigidity, and ultimate compressive strength. The comparative results show slightly lower flexural performance but equivalent or slightly higher compressive strength for structural post member fabrications when constructed from the supply of reclaimed decking material. These results help to demonstrate the technical feasibility or reuse potential of recycled decking for this type of second-generation application.