Effects of Veneer Treatment with Copper-Based Preservatives on the Decay Resistance and Mechanical Properties of Poplar LVL

Abstract

To improve the durability of poplar laminated veneer lumber (LVL), the veneers were impregnated with alkaline copper quaternary (ACQ) and copper azole (CA) at four retention levels, and the effects of the treatments on the LVL properties were examined. The results demonstrated that the treatments substantially improved the decay resistance of LVLs, with the decreases in mass losses ranging from 42.6% to 87.3%. However, retention levels greater than the specified standard values for Use Category C4.1 might be required for sufficient protection of poplar LVL against decay fungi. The bending and shear properties of all treated LVLs met the requirements for high-grade products specified in the LVL standard GB/T 20241. No significant effects of the treatments were observed on the mechanical properties of LVLs, and the LVLs did not display any visible delamination after boil-dry treatment. These results imply that the treatments significantly improved the decay resistance of poplar LVL products and had no appreciable impact on their mechanical and physical properties.