Decay Resistance Research Papers - Academia.edu (original) (raw)

Thermal modified wood has some advantages over natural wood, including decreased hygroscopicity, increased dimensional stability, and enhanced durability. In this study, European species of Scots pine, spruce, and ash and tropical species... more

Thermal modified wood has some advantages over natural wood, including decreased hygroscopicity, increased dimensional stability, and enhanced durability. In this study, European species of Scots pine, spruce, and ash and tropical species of iroko and tali were thermally treated at 180 °C and 210 °C for 1.5 and 2 hr, respectively. We evaluated the resistances of the untreated and thermally treated samples to decay induced by the white rot fungus, Trametes versicolor and two brown rot fungi, Coniophora puteana (C. puteana) and Postia placenta. In addition, the samples were exposed to the termite Reticulitermes grassei and the longhorn beetle species Hylotrupes bajulus to evaluate their resistance to damage by the insects. During the heat treatment, the mass loss of the samples generally was between 9 and 14%. After the heat treatment, experiments were conducted to determine the effects of white and brown rot fungi on samples of Scots pine and tali, the effect of C. puteana on spruce,...

In this study, we aimed evaluate the behavior of the brown-rot fungus Gloeophylum trabeum and white-rot fungus Pycnoporus sanguineus on thermally-modified Eucalyptus grandis wood. To this end, boards from five-year-eleven-month-old E.... more

In this study, we aimed evaluate the behavior of the brown-rot fungus Gloeophylum trabeum and white-rot fungus Pycnoporus sanguineus on thermally-modified Eucalyptus grandis wood. To this end, boards from five-year-eleven-month-old E. grandis trees, taken from the Duratex-SA company stock, were thermally-modified between 180 °C and 220 °C in the Laboratory of Wood Drying and Preservation at Universidade Estadual Paulista-UNESP, Botucatu, Sao Paulo state Brazil. Samples of each treatment were tested according to the ASTM D-2017 (2008) technical norm. The accelerated decay caused by the brown-rot fungus G. trabeum was compared with the decay caused by the white-rot fungus P. sanguineus, studied by Calonego et al. (2010). The results showed that (1) brown-rot fungus caused greater decay than white-rot fungus; and (2) the increase in temperature from 180 to 220 °C caused reductions between 28.2% and 70.0% in the weight loss of E. grandis samples incubated with G. trabeum.

Wood heat treatment is an attractive alternative to improve decay resistance of wood species with low natural durability. However, this improvement of durability is realized at the expense of the mechanical resistance. Decay resistance... more

Wood heat treatment is an attractive alternative to improve decay resistance of wood species with low natural durability. However, this improvement of durability is realized at the expense of the mechanical resistance. Decay resistance and mechanical properties are strongly correlated to thermal degradation of wood cells wall components. Mass loss resulting from this degradation is a good indicator of treatment intensity and final treated wood properties. However, the introduction of a fast and accurate system for measuring this mass loss on an industrial scale is very difficult. Nowadays, many studies are conducted on the determination of control parameters which could be correlated with the treatment conditions and final heat treated wood quality such as decay resistance. The aim of this study is to investigate the relations between kinetics of temperature used during thermal treatment process representing heat treatment intensity, mass losses due to thermal degradation and conferred properties to heat treated wood. It might appear that relative area of treatment temperature curves is a good indicator of treatment intensity. Heat treatment with different treatment conditions (temperature-time) have been performed under vacuum, on four wood species (one hardwood and three softwoods) in order to obtain thermal degradation mass loses of 8, 10 and 12%. For each experiment, relative areas corresponding to temperature kinetics, mass loss, decay resistance and mechanical properties have been determined. Results highlight the statement that the temperature curves’ area constitutes a good indicator in the prediction of needed treatment intensity, to obtain required wood durability and mechanical properties such as bending resistance and Brinell hardness.