QUALITY OF GRUE-BOND EUCALYPTUS WOOD SPECIMEN GLUED IN TWO DIFFERENT DENSITIES AND SHEAR PLANES

Abstract

This work evaluate a glue-bond quality was also determined according to NBR 7190/97 in samples representing the two different densities and the shear planes. Eucalyptus lumber was purchased in the local market for the research purpose. It was foun, that the whole lot could be segregated into two sub-lots, one containing higher specific gravity timber, another containing lower density wood, later, in samples made to represent the two different densities; the shear planes, however, included two possibilities: the two pieces that formed the block had their fibers both parallel or one of the parts had their fibers perpendicular to those of the other part. The adhesive used was resorcinol formaldehyde. Shear strength was determined by compression using these blocks; the percentage of wood failure was also measured. It was found that the low density wood glued better, because the average shear strength of the blocks with fibers of the parts parallel to the direction of the force did not differ from the shear strength of solid wood. It was found the behavior of shear planes follows that of the samples made with fibers of the parts parallel to the shearing force.