Time of Exposure at 60 °C Service Temperature: Influence on Strength and Modulus of Elasticity in Compression Parallel to the Grain of Hardwood Species

The aim of this research was to determine the influence of exposure time at 60 degrees C in the compression strength parallel to the grain (f(c0)) and modulus of elasticity in compression parallel to the grain (E-c0) for cupiuba (Goupia glabra), eucalypt (Eucalyptus saligna), garapeira (Apuleia leiocarpa) and jatoba tamarindo (Hymeneae sp.) wood species. The factor investigated in this research was the residence time in kiln (exposure at controlled temperature 60 degrees C) of specimens: 0 (wood tested at room temperature and moisture content around to 12%), 168, 456, 720, and 2160 hours, simulating the reaction of the material in confined roof structures. Compression parallel to the grain tests were conducted according to the methods of the Brazilian Standard Code ABNT NBR 7190 (1997). ANOVA results indicated that the temperature (60 degrees C) had a significant influence in the five exposure times. All studied wood species showed an increase in the f(c0 )value with increasing time of exposure at 60 degrees C. For E-c0, this phenomenon occurred only for the jatoba tamarindo and cupiuba wood species.