Effects of layered structure on the physical and mechanical properties of laminated moso bamboo (Phyllosachys edulis) flooring

The physical and mechanical properties of five different layered structure types of laminated moso bamboo (Phyllosachys edulis) flooring (LBF) were investigated in this study. In addition, the dynamic modulus of elasticity (DMOE) calculated from ultrasonic wave velocity was also investigated. A good correlation between the DMOE and modulus of rupture (MOR) values of the LBF was found (R2 = 0.92, p < 0.01). Results indicated that the DMOE can be a predictor of the bending properties of LBF. The mean linear length expansion value of the cross-laminated layered structure type LBF (group V) was higher than those of the other types. Overall, the mean thickness swelling, water absorption, linear width, and thickness expansion values obtained from group V were smaller than those from the other groups. Thus, group V should be of a better quality than the other groups from the viewpoint of its dimensional stability. The cross-laminated type (group V) of a layered structural design affected the MOE and MOR values significantly less than those of the other groups. However, the mean bending strength (87.5 MPa) of group V was suitable for flooring purposes, in addition, concerned to the orthotropic bending properties of group V, defined as the ratio of bending properties parallel to fiber direction (MOE(para), MOR(para)) to those perpendicular to fiber direction (MOE(perp), MOR(perp)) were 1.28 for MOE(para) to MOE(perp) and 1.20 for MOR(para) to MOR(perp), respectively. sults suggest that it is feasible to evaluate the bending properties of LBF using the DMOE, and group V should be a better choice than the other groups to meet the basic necessities for flooring purposes.