Mistura de três espécies de reflorestamento na produção de painéis cimento-madeira

Abstract

The objective of this work was to evaluate the technical feasibility of producing cement-wood panels made up from different proportions of Australian cedar (Toona ciliata M. Roem.), Eucalyptus grandis x Eucalyptus urophylla and Pinus taeda wood wastes using two different curing procedures: acclimation and vaporization. Portland CP V - ARI/Plus cement was used as binder and calcium chloride as additive. The wood particles were previously treated in water for 24 hours. The following parameters were considered for the estimation: wood/cement ratio- ½.75; water/cement ratio - ½.5 (based upon cement weight); hydration water/cement ratio - 25% (based upon cement weight); chemical additive - 4% (based upon cement weight); target density - 1.10 g/cm3; panel dimensions - 480 x 480 x 150 mm. The pressing parameters were the following: room temperature, specific pressure of 40 kgf/cm2 and a time period of 10 minutes. Clasping time was 24 hours. The properties evaluated were water absorption and thickness swelling after 24 hours, static bending, compression and internal bonding. Experimental statistical design was entirely randomized with three replications and six treatments, arranged in a factorial design of 3 compositions and 2 curing procedures. Panels made from T. ciliata and Eucalyptus grandis x Eucalyptus urophylla presented higher average values for thickness swelling and inferior values for most mechanical properties. Vaporization cure improved physical properties, but negatively influenced most of mechanical properties.