Mechanical properties of oriented bamboo scrimber boards made of Phyllostachys pubescens (moso bamboo) from Taiwan and China as a function of density

The properties of oriented bamboo scrimber boards (OBSB) have been investigated at three density levels (0.8, 0.9, and 1.0 g cm3), while the boards were made from moso bamboo (Phyllostachys pubescens) grown in Taiwan (T-OBSB) and China (C-OBSB). A non-destructive technique (NDT), ultrasonic-wave velocity (Vu) measurements were applied and the dynamic modulus of elasticity (MOEdyn) was calculated. Moreover, static modulus of elasticity (MOE), modulus of rupture (MOR), profile density distribution, internal bond strength (IB), springback (SB), and dimensional stability were determined based on traditional methods. Positive linear relationships between density and Vu, MOEdyn, MOE and MOR were observed, no matter if the measurements were done parallel (//) or perpendicular (⊥) to the fiber direction of the OBSBs. Moreover, Vu(//), MOEdyn,u(//), MOE(//), and MOR(//) were higher than Vu(⊥), MOEdyn,u(⊥), MOE(⊥) and MOR(⊥). C-OBSB had slightly lower Vu(//), Vu(⊥), MOEdyn,u(//) and DMOEu(⊥) values than T-OBSB. T-OBSB had higher MOE(//), MOE(⊥) and MOR(//) than C-OBSB, but less MOR(⊥). The profile density distribution of high-density T-OBSB showed singnificant data scattering. The profile density distribution of C-OBSB was homogeneous at all density levels. IB and SB data are directly proportional to density, but water absorption, thickness swelling and volumetric swelling are inversely proportional to density. T-OBSB has better bonding and strength properties, and dimensional stability than C-OBSB