Abstract
Use of engineered wood products, particularly structural glued laminated timber and/or cross-laminated timber (CLT), is indispensable for recent large-scale wooden buildings. Durability of adhesion of these materials is quite important for assurance of reliable mechanical properties throughout their service life. Therefore, only some highly reliable adhesives are permitted for use. Resorcinol resin adhesive has been used for a long time as a load-bearing structural wood adhesive. In addition, new structural adhesives such as the aqueous polymer-isocyanate adhesive developed in Japan and one-component polyurethane adhesives for structural use developed in Europe have recently been initiated for use in structural glued laminated timber and CLT. These isocyanate-based resin adhesives are different from resorcinol resin in terms of their chemical structure and physical performance. Therefore, the requirement of bond qualities of structural wood adhesives has been reconsidered, and standards have also been maintained in each country. Here the present standards for structural wood adhesives and evaluation methods for their bond performance are reviewed.
