2018 Volume 64 Issue 4 Pages 149-155
To investigate the influence of preservatives on bond durability of glued-laminated-timber (GLT), sugi (Cryptomeria japonica D.Don) laminae were impregnated with five kinds of wood preservative (ACQ, NCU, CUAZ2, NZN, and AAC), and 5-ply GLTs of low and high density were fabricated using resorcinol-formaldehyde (RF) and phenol-resorcinol-formaldehyde (PRF) resin adhesives. They were subjected to 10 years of outdoor exposure testing, and after 1, 3, 5, and 10 years of exposure, block-shear tests were conducted. As the result, bond shear-strength decreased with exposure duration regardless of adhesive resin in GLT treated with ACQ, NCU, and CUAZ2, which contain copper as the main ingredient. The rate of decrease of bond shear-strength of GLTs treated with ACQ, NCU and CUAZ2 was greater when using RF than when using PRF. Comparing the bond shear-strengths of high and low density GLTs, it was recognized that decrease of bond shear-strength was greater for high density than for low density GLTs. Decrease of wood-failure ratio with exposure duration was low for all GLTs.
