Abstract

CALONEGO, Fred Willians; SEVERO, Elias Taylor Durgante  and  BRITO, Aline Fernanda de. Types of Failures in Thermally-Modified Eucalyptus grandis Wood. Silva Lus. [online]. 2013, vol.21, n.Especial, pp.153-161. ISSN 0870-6352.

This study aimed to evaluate the types of failures after the mechanical tests of thermally-modified Eucalyptus grandis wood. The present study utilized boards that contained the pith from 5 years and 11 months old Eucalyptus grandis trees. The boards were dried up to 10.0% moisture content, planing to 32-mm thick, and cutted into smaller pieces measuring 0.60 m in length. Subsequently, one piece was kept in its original condition and others pieces were thermally-modified at 140ºC, 160ºC, 180ºC, 200ºC and 220ºC over a period of 2.5 hours. Specimens were obtained for the compression-parallel­to-grain and static-bending tests. All of the specimens were placed in a climatic chamber (21ºC and 65% relative humidity) in the Laboratory of Wood Drying and Preservation in the Department of Natural Resources/Forest Sciences, FCA-UNESP, Botucatu-SP, in Brazil. After the mechanical tests the types of failures were classified as recommended by ASTM D-143 (2007). The results show that: (1) there is a direct relationship between the heat treatment temperature and brittle wood by chi-square test; and (2) the E. grandis wood when thermally-modified at 220ºC presented 100% of fragile failure.

Keywords : thermally-modified wood; Eucalypts; fragile failures; compression parallel to grain; static bending.

        · abstract in Portuguese     · text in Portuguese     · Portuguese ( pdf )