The influence of humidity on mechanical properties of bamboo for bicycles

Bamboo as an eco-friendly material has potential as construction material and proves his suitability in use as an alternative for more traditional materials such as steel, aluminium and composite. This work presents the influence of humidity on mechanical properties of two different bamboos, Pseudosasa amabilis (or Tonkin Cane) and Pleioblastus amarus (or Ku Zhu) which are used for bicycle frames. A large number of tensile, compression and bending tests were carried out in two conditions, dry (in terms of the environment) and wet (after 3 weeks in wet chamber). It is shown that both, Tonkin Cane and Ku Zhu, in spite of low change in weight after 3 weeks in wet chamber have lower values of mechanical properties. The results show that the tensile, compressive and bending strength of bamboo significantly decreased after bamboo samples were kept in an environment with humidity level of 60%. The reduction of strength in the wet state for both types of bamboo is statistically proven by two sample comparisons of their arithmetic means at significance level α = 0.05. The results of this study indicate that the minimum change of moisture in samples decreases bending, tensile and compression strength of bamboo. Potential application of the results of this research is in the design and production of bicycle frameworks.