Este trabalho teve por objetivo avaliar o efeito do tratamento das partículas, da variação da relação madeira:cimento e da utilização de aditivos químicos sobre as propriedades físicas e mecânicas das chapas minerais fabricadas com partículas de Eucalyptus dunnii (Maid) combinada com cimento portland. Foram empregados três tratamentos de partículas (partículas sem tratamento, tratadas com água quente por 1 h a 80°C e tratadas com NaOH a 1%, por 24 h), duas relações madeira:cimento (1:2,5 e 1:3,0) e dois aditivos químicos (CaCl 2 e MgCl 2). Foram realizadas análises das propriedades físicas e mecânicas das chapas e os resultados demonstraram que, dentre os três fatores analisados, o tratamento das partículas foi o que causou efeito mais pronunciado sobre as propriedades das chapas, interferindo negativamente nos resultados. O aditivo químico que melhor desempenho apresentou foi o MgCl 2 .
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 °C; and particles treated with NaOH 1% for 24 hours; two wood:cement ratios (1:2.5 and 1:3.0), two chemical additives (CaCl 2 and MgCl 2 ) 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, MgCl 2 was the chemical additive with better performance.
