Bamboo lumber – an innovative sustainable raw material and an accelerated weathering study for establishing its durability

Bamboo lumber was prepared using Bambusa bamboos species and its weathering performance was evaluated under natural and accelerated weathering. Specimens of bamboo lumber were exposed to natural weathering for 150 days. Another set of specimens were exposed to UV light source (UVA 360) in accelerated weathering tester up to 250 hours. A comparative study on the level of degradation in natural and accelerated weathering was made by evaluating CIEL*a*b* colour changes measured using a Hunter lab spectro-colorimeter. Rate of color change due to photo-degradation were evaluated. Results showed that all three color axes, viz. lightness (L*), redness (a*) and yellowness (b*) changed linearly with respect to time under natural exposure, but only L* was changed under accelerated weathering, keeping a* and b* values to be almost constant. Photodegradation of bamboo was mainly due to UV light absorption by chromophores present in the lignin, which constitutes about 32,2 % of total bamboo.