Rachel A. Arango

Fifty-Year Durability Evaluation of Posts Treated with Industrial Wood Preservatives

Abstract Long-term durability data are needed to improve service life estimates for treated wood products used as critical structural supports in industrial applications. This article reports the durability of longleaf pine (Pinus palustris) posts pressure treated with ammoniacal copper arsenate (ACA), chromated copper arsenate (CCA), creosote, or pentachlorophenol and exposed for 50 years in southern Mississippi. During inspections, posts were subjected to a pass/fail evaluation by applying a load to the top of the post. No failures occurred in any of the 125 posts treated with CCA or in any of the 75 posts treated with pentachlorophenol. Three of 25 ACA-treated posts and 5 of 25 creosote-treated posts failed. Estimated times to 50 percent failure in the ACA- and creosote-treated posts were calculated as 96 and 78 years, respectively. The estimated years to failure for the CCA- and pentachlorophenol-treated posts could not be calculated because of the lack of failures but presumably would be greater than...

Northeastern United States species treated with copper-based preservatives: Durability in Mississippi stake tests

This paper reports on the ground-contact durability of lesser-used wood species of the northeastern United States after treatment with copper-based preservatives. Stakes (19 by 19 by 457 mm) cut from balsam-fir (Abies balsamea), eastern hemlock (Tsuga canadensis), eastern spruce (mixture of Picea glauca, Picea mariana and Picea rubens), red maple (Acer rubrum) or eastern white pine (Pinus strobus) were treated with one of four concentrations of chromated copper arsenate type C (CCA-C), copper citrate (CC), alkaline copper quat type C (ACQ-C) or copper azole type A (CBA-A) and placed into the ground at a test site in southern Mississippi. Similarly treated southern pine (Pinus spp.) stakes were included for comparison. The stakes were rated for decay and termite attack after 1, 2, 3, 4, 5, 8, 10 and 12 years. Eastern white pine and incised eastern hemlock and balsam-fir had durability similar to southern pine when treated with CCA or the other copper-based preservatives. Eastern spruce was less durable than the other softwood species, apparently because of low preservative uptake. Red maple had the least durability at all retentions and for all preservatives. This study indicates that several northeastern softwoods can be adequately durable when pressure-treated with CCA-C or copper-based preservatives.