In end-jointing of laminae for the glulam timber, finger-joint is generally used. However, the strength properties of the glulam timber greatly decrease by slippage-off and destruction in starved joints of fingerjointed part when the laminae with starved joints in the finger-joint are located on the external layer of the glulam timber. Therefore, for the glulam timber with good strength properties, the evaluation of finger-joint properties after finger-jointing is important, and the method is hoped to be simple and non-destructive. In this study, to examine the optimum adhesive condition in finger-joint part which influences strength properties of the large-scale sugi finger-jointed laminae, the block shear tests with sugi block specimens which assumed finger-joint part and glued under various adhesive conditions was performed. The main results are summarized as follows: In the case of the specimen of W-O (With curing agent, One side spreading) under 40-20 (open assembly temperature and time set to 40'C and 20 min) with resorcinol phenol resin type adhesive, the tendency to decrease of the shear strength was shown. From the fracture morphology, the reason was considered that the adhesive did not transfer on none-spreading side because the surface of the adhesive has stiffened by setting the open assembly temperature and time. In other conditions, an enough glued performance was considered because the shear strength showed a comparatively large value. Moreover, in the case of None-specimen (Without curing agent), the shear strength shows a small value and the tendency to decrease was shown by setting the open assembly temperature and time. In three conditions of W-O, None-B (Without curing agent, Both sides spreading), and None-0 (Without curing agent, One side spreading) under 40-20 with aqueous polymer solution-isocyanate adhesive, the shear strength had decreased remarkably. In other conditions, the difference was not admitted and the tendency to decrease of the shear strength was shown by setting the open assembly temperature and time.
|Number of pages
|Journal of the Faculty of Agriculture, Kyushu University
|Published - Feb 2013
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science