The temperature effect on the compressive performance of laminated bamboo lumber

To investigate the effect of temperature on the compressive performance of laminated bamboo lumber (LBL), 198 specimens were tested in three loading directions (parallel to the grain and perpendicular to the grain in both flatwise and edgewise sections) under exposure to 11 different temperatures in the range −60°C to 200°C. Through the macroscopic failure modes summarised by damage characteristics and microscopic vascular bundles observed by scanning electron microscopy, the failure mechanisms of LBL under different temperatures was analysed. The average compressive strength of the specimens in the three loading directions (parallel, perpendicular flatwise and perpendicular edgewise) at 20°C was 45.07, 12.13 and 10.75 MPa, respectively. The compressive strength in the three directions increased by more than 80% at the lowest temperature (−60°C), while the loss of compressive strength exceeded 70% at the highest temperature (200°C). This was due to thinning of the bamboo cell walls at high temperature, ultimately resulting in the disappearance of the layered structure of cell walls and thus the loss of bearing capacity. An empirical formula was developed to calculate the temperature effect factor for compressive strength varying with temperature.