Quasi-static and dynamic compressive behavior of bamboo scrimber subjected to air-dried, aged, and saturated treatments

Bamboo scrimber, as an eco-friendly and sustainable biomass composite material, holds significant potential for structural applications. However, its structural use exposes it to potential dynamic impact loads, hygrothermal conditions, and inevitable aging. A comprehensive understanding of its dynamic compressive behavior is essential for the impact-resistant design of bamboo scrimber structures. In this study, the quasi-static and dynamic compressive mechanical properties of bamboo scrimber are investigated across a range of strain rates, from 6.7 × 10⁻⁴ s⁻¹ to around 700 s⁻¹. The influence of two loading directions (longitudinal and transversal) and three specimen conditions (air-dried, aged, saturated conditions) on strain rate effect and energy absorption of bamboo scrimber is evaluated. Test results show that the yield and ultimate compressive strengths of bamboo scrimber increase nonlinearly with strain rate. The Dynamic Increase Factors (DIFs) for these strengths can be effectively described as a function of strain rate using the classical Cowper–Symonds (C-S) model. Under compressive loading, both aged and saturated bamboo scrimber exhibit higher strain rates and more severe damages, but lower mechanical properties and energy absorption than air-dried specimens. Additionally, aging treatment significantly reduces the DIF of the yield and ultimate compressive strength, primarily due to the degradation of inter-fiber bonding behavior in bamboo scrimber. In contrast, saturation treatment enhances the DIF under transversal impact loading while having minimal influence on the DIF under longitudinal impact. Under low-velocity impact, air-dried bamboo scrimber is more susceptible to the micro-inertia effect than to shock wave phenomena, regardless of the impact loading direction.