Evaluation of the bonding process and interlaminar shear properties of hybrid cross-laminated timber prepared with larch and OSB

This study explores the application of oriented strand board (OSB) to hybrid cross-laminated timber (HCLT). OSB and larch were used to fabricate hybrid forms of HCLT for analysis. Firstly, the impact of surface treatment on OSB was investigated in terms of its influence on the bonding line between materials, encompassing both pre-treatment and post-treatment surface properties of OSB. The findings indicate that sanding has the ability to alter the surface properties of OSB, leading to an increase in surface roughness and surface free energy, and reduce the pre-cured layer. Notably, there is no significant disparity observed in both the shear failure mode and shear strength of the bonding line of CLT, and the failure is in the core layer of OSB. Secondly, two layups of HCLT were prepared by combining OSB with larch. The interlaminar shear strength was assessed in both the major and minor strength directions using a three-point bending test. The results showed that, due to the low density and mechanical properties of the core layer of OSB, its application in HCLT as perpendicular layer is not a favorable choice, because it cannot prevent the rolling shear failure in perpendicular layer, and it also diminishes the interlaminar shear strength of HCLT in the minor strength direction. However, the interlaminar shear strength increases in the minor strength direction when OSB was used as the parallel layer, and larch was used as the perpendicular layer, even stronger than that in major strength direction.