Correlations between moisture expansion and flexural properties of bamboo strips in response to different loading rates

Abstract

Bamboo and bamboo products, known for their hygroscopic nature, exhibit sensitivity to different loading rates in dry conditions. However, with the increasing prevalence of heavy and extended precipitation events due to global warming, there is still a lack of investigation on the response of bamboo strips to various loading rates after being attacked by moisture. In this study, the bending properties of bamboo strips after exposure to extremely high-humidity environments were investigated to assess their responses to varying loading rates. Throughout different exposure durations, bamboo strips exhibited varying moisture contents up to 112% and evident volumetric moisture expansion. After moisture exposure, bamboo strips exhibited heightened sensitivity in flexural strength and modulus to loading rates, with the most pronounced sensitivity observed at 33.9% moisture content. In addition, a linear relationship was established between flexural strength loss and volumetric expansion rather than moisture content. Notably, the samples exhibited greater sensitivity in strength loss to moisture expansion under lower loading rates. These findings preliminarily elucidate how loading rates impact the mechanical properties of bamboo strips across varying moisture levels, contributing to understanding the deterioration in the properties of engineered bamboo products when exposed to high humidity and rainy environments with potential collision events.