The Effect of Pressure on Retention and Bending Properties of Copper Naphthenate and CCA Type C Treated Hardwoods
Keywords:CCA, Cu-N, copper naphthenate, hardwood, retention, pressure treatment, bending
AbstractThe objective of this study was to investigate the effect of the pressure level on retention and bending strength of some northern hardwood species after preservative treatment. Samples of red maple, sugar maple, beech, and red oak were pressure-treated with waterborne chromated copper arsenic (CCA) type C or with oilborne copper naphthenate (Cu-N) at four pressure levels: 0.69, 1.03, 1.38, 2.07, and 2.76 MPa. At a pressure level of 0.69 MPa (200 psi) for 2 h, retentions of 4.5 kg/m3 elemental copper from copper naphthenate and 10 ± 2 kg/m3 total oxides from chromated copper arsenate (CCA) were achieved for maples. The pressure level did not affect the retention of Cu-N in red maple, sugar maple, and red oak; the same observation was made for CCA in maples. A pressure level of 2.76 MPa was needed to obtain a 7.5 kg/m3 CCA retention and 1.08 kg/m3 copper metal in Cu-N-treated beech. Copper naphthenate treatment did not affect the bending strength, while CCA-treated samples exhibited a reduced bending strength between 0 and 33% depending on the species, pressure level, and preservative type.
American Society for Testing and Materials (ASTM). 1996. Standard method of testing small clear specimens of timber. D-143-94. Vol. 04.10 on Wood. Annual Book of ASTM Standards, West Conshohocken, PA.nAmerican Wood-Preservers' Association (AWPA). 1997. Book of Standards. Woodstock, MD.nBehr, E. A. 1967. Preservative treatment of beech by soaking. Michigan Agricultural Experiment Station, Bull. Michigan State University, East Lansing, MI.nBehr, E. A., I. B. Sachs, B. F. Kukachka, and J. O. Blew. 1969. Microscopic examination of pressure-treated wood. Forest Prod. J. 19(8):31-40.nButcher, J. A. 1979. Soft-rot control in hardwoods treated with chromated copper arsenate preservatives. V. A reason for variable performance of CCA treated hardwoods. Mater. Org. 14:215-234.nDe Groot, R. C., C. L. Link, and J. B. Huffman. 1988. Field trials of copper naphthenate treated wood. Proc. Am. Wood Preserv. Assoc. 84:186-200.nForest Products Laboratory (FPL). 1987. Wood handbook: Wood as an engineering material. Agric. Handb. 72, rev. U.S. Department of Agriculture, Washington, D.C. 466 pp.nGrace, J. K., R. T. Yamamoto, and P. E. Laks. 1993. Evaluation of the termite resistance of wood pressure treated with copper naphthenate. Forest Prod. J. 43(11/12):72-76.nHunt, G. W., and G. A. Garratt. 1938. Wood preservation. 1st ed. McGraw-Hill, NY. 457 pp.nKamdem, D. P., K. Gruber, and M. Freeman. 1995. Laboratory evaluation of copper naphthenate as wood preservative for northern red oak. Forest Prod. J. 45(9):72-76.nMicklewright, J. T. 1993. Wood preservation statistics, 1991. A report to the wood-preserving industry in the United States. Am. Wood-Preserv. Assoc., Woodstock, MD.nPizzi, A., W. E. Conradie, and M. Bariska. 1986. Polyflavonoid tannins—from a cause of CCA red dot failure to the "missing link" between lignin and microdistribution theories. Inter. Res. Group on Wood Preserv. Doc. IRG/WP/3359. Stockholm, Sweden.nRichards, J. M., and S. W. McNamara. 1997. The field performance of CCA type C treated sawn refractory redwoods from North America. Int. Res. Group on Wood Preserv., IRG/WP/40085. Stockholm, Sweden.nWalters, C. S. 1967. The effect of treating pressure on the mechanical properties of wood: I. Red gum. Proc. Ann. Wood-Preserv. Assoc. 63:166-186. Woodstock, MD.nWinandy, J. 1995. Effects of waterborne preservative treatment on mechanical properties: A review. Proc. Am. Wood Preserv. Assoc. 91:17-33.n
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.