Evaluation of Mechanical Properties of Cross-Laminated Timber with Different Lay-ups Using Japanese Larch

Japanese larch is one of the main plantation tree species in China A lack of engineered wood products made by Japanese larch, however, limits its application in wood structures. In this study, based on optimum process parameters, such as pressure (1.2 MPa), adhesive spread rate (200 g/m(2)) and adhesive (one-component polyurethane), the mechanical properties of Japanese larch-made cross-laminated timber (CLT) with different lay-ups were evaluated by means of the static method. Results of this study showed that variations in lay-ups significantly affected the mechanical properties of CLT. The strength and modulus of bending and parallel compression for CLT increased with the thickness of lumber, while that of bending, parallel compression and rolling shear all decreased with the number of layers. Thickness, layup orientation and the number of layers all had an impact on the strength of CLT. Failure modes obtained from numerical simulation were basically the same as those of experimental tests. There was also strong alignment between theoretical value and test value for effective bending stiffness and shear stiffness. Thus, the shear analogy method can be used to predict the mechanical properties of CLT effectively. This study proved great potential in using Japanese larch wood for manufacturing CLT due to its good mechanical properties.