Influence of temperature on the mechanical properties of engineered bamboo laminate

Abstract

Engineered bamboo (EB) products as a promising biocomposite construction material are increasingly used, and the fire resistance capacity is one of its governing design considerations. This research aims to obtain the basic mechanical properties of two types of engineered bamboo laminate panels used for glubam structures, unidirectional and multidirectional bamboo, exposed to elevated temperatures. The increasing temperature from 20 ℃ to 220 ℃ and different loading conditions, including during heating, shortly after heating in 15–30 mins, and heating plus 48 h of maintenance (20℃, 65% relative humidity-RH) were considered in this research. The experimental studies on compression, tension, and bending were conducted. The variables involved in these tests were heating time, specimen height, heating temperature, loading condition, and bamboo panel type. Corresponding failure modes and test results were summarized. Test results showed that three heating times used in this research had little influence on the mechanical performance of EB panels. The elastic parameters of engineered bamboo changed apparently during and after the heating process. All mechanical properties experience an apparent degradation during the heating condition but would recover and even gain higher compressive and bending strength and stiffness in certain temperature regions after the heating. The 160 ℃ was observed as an essential temperature to change the properties of the bamboo panel. Meanwhile, a simplified stress–strain relationship model with reduction factors based on data obtained from compression and tension tests was developed to analyze the bending performance of bamboo members under different elevated temperatures and maintenance conditions. Simulation results indicated that this model could provide reasonable predictions for estimating the residual fire resistance capacity of glubam members.