Influência do tratamento preservativo com CCA nos defeitos visuais e nas propriedades físicas e mecânicas da madeira serrada de Pinus taeda L.

Abstract

The wood of Pinus taeda L. is widely recognized in the international timber market. A considerable part of this market is given to the production and commercialization of sawn timber from the conifer. As a procedure for processing sawn timber, wood treatment is a driving force in this market since the treatment aims to add value to the product by protecting the sawn timber against biodegradable agents such as fungi, bacteria, insects and marine borers. Among the wood treatment methods, the procedure carried out in an autoclave (Bethell method) has been used due to its high production capacity and effectiveness. However, it was observed that the application of the preservative product at high pressure has caused defects in the sawn timber. Thus, the objective of this study was to analyze the influence of the preservative treatment with CCA on the visual defects and physical-mechanical properties of sawn timber from Pinus taeda. Knots and cracks were evaluated through visual classification (NBR 7190-2: 2022), and physical properties (moisture content and apparent specific mass) and mechanical tests (compression parallel to the fibers and bending perpendicular to the fibers) were determined using Brazilian standard 7190-3:2022. The results obtained showed that the treatment influenced the occurrence of cracks through evaluation using the Wilcoxon signed-rank test. However, the cracks present after the treatment were not significant for disqualification by the NBR 7190-2 standard. Regarding the mechanical results, it was possible to see that the treated wood obtained better resistance performance for the flexural strength test and equivalent performance for the compression test, both at 5% significance for the Student's t-test and ANOVA analyses.