Interlaminar shear strength of multi-layered oriented strength board from plantation species

A Study was conducted to determine the interlaminar shear strength properties of multilayered oriented strand boards (OSB). Boards produced were 12 X 360 X 360 mm in dimensions. The strands with predetermined dimensions were blended with phenolformaldehyde resin (53.2% solid content) at 5 and 7 percent resin content. A Five-point Bending Test (ASTM D 1037) and Span Length Shear Test (AsTM D 2718) were used to assess the interlaminar shear strength (S-max) of specimens cut from the oriented strength boards (OSB). Two sets of test specimens (each of Hevea brasiliensis and Acacia mangium, respectively) were tested with each set consisting of three types of OSB specimens. The OSB types were 3-layered, five-layered and veneer laminated seven-layered OSB. This study showed that the board types affected the interlaminar shear strength significantly in both type of tests. Shear failure were primarily in the core layer in the regions of maximum shear forces between the active loads and the supports. No bending failure was recorded for all specimens tested. The laminated OSB boards did not fail in shear in the glue interface between the lamination material and the OSB. Increasing the number of layers will decrease the value of interlaminar shear strength. The OSB fabricated from acacia had higher value in S-max, therefore it is more suitable for structural applications where shear strength is important compared to rubberwood OSB such as flange rather than web in an I-joist structural system.