Efeitos do tratamento das partículas de Eucalyptus dunnii (Maid), da variação da relação madeira-cimento e do uso de aditivos sobre as propriedades físicas e mecânicas de chapas de madeira-cimento

Abstract

This research assesed the technical feasibility of the production of mineral boards, through the utilization of Eucalyptus dunnii particles, and evaluated the particles treatments efficiency, the influence of the wood:cement ratio variation and the use of chemical additive. The used cement was the commercialy available Portland type. Three particles treatments were analized: particles without treatment; particles treated with hot water for 1 hour at 80 ºC; and particles treated with NaOH 1% for 24 hours; two wood:cement ratios (1:2.5 and 1:3.0), two chemical additives (CaCl2 and MgCl2) and their effects over physical and mechanical properties of boards. The assessed physical and mechanical properties were: static bending; parallel compression; internal bond; and dimensional stability (water absorption and thickness swelling after immersion in water). The results were statistically analyzed through factorial analysis of covariance. Among the analyzed factors, particles treatments caused a more pronounced effect on the boards properties, with a negative contribution to the results. The increment of the wood:cement ratio did not showed higher average values for the mechanical properties, except for the internal bond. In general, MgCl2 was the chemical additive with better performance.