The wood is one of the most versatile building materials, however considering the
environmental pressures associated with lack of native wood in the South and Southeast
region, alternatives woods must be used. The Eucalyptus species are a solution to this problem
however they have limitations such high levels of growth stress, high shrinkage, low
permeability, drying defects and susceptibility to rot fungi. A commercially attractive way to
improve the dimensional stability and durability of these products is this retification® process
after its drying. The objetive of this work was evaluating the effect of retification®, under
different temperatures on the quality of the Eucalyptus grandis Hill ex Maiden wood. In order
to do it so, were used logs of Eucalyptus grandis trees, with 5.9 years of age from company
Duratex-SA. Each board was cutting to provide pieces and those designed with control and
retified® with temperatures of 140oC, 160oC, 180oC, 200oC and 220oC. The quality of retified®
wood was determined by the following tests (1) mass loss and tickness variation of boards; (2)
physical properties (densities at 0%, 12.0% and 17.5% of moisture content, equilibrium
moisture content, volumetric and linears swelling, shrinkage coeficient and anisotropic factor);
(3) decay resitance of wood; and (4) mechanical properties (compression parallel to grain,
static bending and Janka hardness perpendicular to grain). The results showed that: (1) the
mass loss of Eucalyptus grandis boards exponentially increases from 0.004% to 5.7% with an
increase of retification® temperature; (2) near pith there is a variation in the boards thickness
reduction of up 99.6% with an increase of treatment temperature, while near bark this
variation was of up to 18.5%; (3) with increase retification® temperature has an significant
improvements on moisture content and volumetric, tangential, radial and longitudinal swelling
in theirs shrinkage coefficients of up 49.3% and 58.8%, 62.7%, 50.0%, 77.4% and 26.9%,
6.9% and 30.6%, respectively; (4) the retification® between 140oC and 220oC had a decreased
of mass loss from 5.1% to 77.4% and from 3.3% to 82.4% for agar-block and soil-block tests
with Picnoporus sanguineus fungus, respectively; (5) the retification® with temperatures
biggest than 180oC to caused significant decreases from 24.0% to 52.3% in the modulus of
rupture in static bending, however no changes were observed on modulus of rupture in
compression parallel to grain and neither on modulus of elasticity for both tests; (6) retified®
woods with temperature up 180oC to presented some samples with fragiles failures, which
were of 100% for heat-treated wood at 220oC; and (7) the temperature increased from 180oC
to 220oC caused significant decreases from 12.1% to 20.7% in Janka hardness perpendicular to
grain.
