Relationships between Strength Properties and Density or Ultrasonic Velocity of Timber Attacked by Termite
Takuro MORI, Akihiro KOUSOKU, Yoshiyuki YANASE and Kohei KOMATSU
Abstract:To evaluate a decrease in strength of wooden members and wood-based materials attacked by termites or wood-destroying fungi is important for long-term maintaining of wooden constructions. The relationships between strength and degree of biodeterioration of wooden members and wood-based materials were not evaluated properly, though there were few techniques for evaluating the degree of biodeterioration in wooden constructions using screwdriver, palpation or other apparatus. In this study, the strengths of three species of wood attacked by termites were evaluated using bending test and compression test of perpendicular to the grain, and the relationships between the strength and the density or the velocity of ultrasonic in the attacked wood were also investigated. As the results, European spruce specimens had large damage comparison with other species. Thus the density of attacked wood was positively correlated with the bending strength and youngfs modulus. The velocity of ultrasonic in attacked wood was loosely correlated with the bending strength and youngfs modulus. In the case of picking up the European spruce material, between the velocity of ultrasonic and bending strength or youngfs modulus showed good correlation. On the other hand, it was not found that the density and the velocity of ultrasonic were positively correlated with the compression strength and youngfs modulus. Key Words:Termite, Bending strength, Compression strength, Ultrasonic velocity, Density, Biodeterioratio