Behavior of glued laminated bamboo in compression perpendicular to the grain at elevated temperature

The study investigated the behavior of glued laminated bamboo (GLB) subjected to compression in different loading configurations. The temperature range of 20 °C to 250 °C and the loading configurations of full surface and local loading perpendicular to the grain direction were considered. The results were discussed in terms of the failure mode, load-deformation curve, and compressive strength, revealing the effect of varying loading configurations and temperatures. In the full surface compression specimens, inclined shear surfaces were observed, while the failure mode of the local compression specimens was characterized by cracks in the adhesive layers. Despite the different failure modes, the load-deformation curves were similar. Due to the confined dilation, the strength under local compression showed higher values than that under full surface compression. As the temperature increases, there is a gradual decrease in both the full surface and local compressive strength. The reduction factors of compressive strength were fitted using a bilinear function. Subsequently, a model, based on van der Put's equation, was proposed for the prediction of full surface and local compressive strength at elevated temperatures. Additionally, the scanning electron microscopy was used to observe the microstructure of thermally treated GLB specimens, and the impact of temperature on morphological changes was discussed.