Avaliação dos efeitos de pré-tratamentos da madeira de eucalyptus benthamii maiden & cambage no grau de compatibilidade com cimento portland1

Abstract

This study aimed to evaluate the effect of five different types of pretreatment on the compatibility between Eucalyptus benthamii wood and Portland cement. The wood was pretreated with cold water, hot water, sodium hydroxide, calcium chloride or calcium hydroxide. Compatibility degree was determined through the study of the heat of hydration on the first 24 hours, and the axial compression strength, after 28 days of the composites made with a 13.3:1 weight ratio for cement and wood powder. The axial compression strength after 28 days was also evaluated for composites made with a 2.75:1 weight ratio for cement and wood particles. The results of the tests made with wood powder indicated that the addition of 3% of calcium chloride is the most efficient treatment to reduce the specie inhibition, while the treatment of the wood powder with calcium hydroxide had a negative effect in the compatibility. However, the combination of calcium chloride additive with carbonated particles through calcium hydroxide treatment presented the highest axial compression strength within the composites made with a cement:wood weight ratio of 2.75:1. The wood of Eucalyptus benthamii has potential for wood-cement panels manufacture. The use of the methodology of particles carbonation in a solution of calcium hydroxide is also viable as pretreatment, independently of the results presented by traditional methods of measuring the compatibility degree.