Investigation of weathering and soil burial effect on physical and mechanical properties of Phyllostachys edulis and Dendrocalamus asper bamboo treated with disodium octaborate tetrahydrate

Abstract

In this study, the effect of natural weathering on the physical and mechanical properties of two types of bamboo, Dendrocalamus asper, and Phyllostachys edulis was investigated. Twelve bamboo culms of each species were prepared, with six from each group treated with an 8% w/v disodium octaborate tetrahydrate (DOT) solution. The culms were half-buried in the soil for 33 months. After this period, the samples were removed, and the appearance condition of the exposed and buried parts was investigated regarding cracks and degradation. For microstructure characterization, the images were analyzed by SEM (scanning electron microscopy) to assess the changes in untreated and treated samples after natural aging. Physical and mechanical tests were carried out on all the samples, pre- and post-weathering. The results indicated no significant difference in the flexural strength of exposed parts between treated and untreated samples. For the buried section of both bamboo species, all untreated samples had rotten. Although the treated culms exhibited less degradation than the untreated ones, their use is not recommended, as the buried portions of the treated bamboo demonstrated more fragile behavior than the exposed parts. Despite the maintenance of mechanical properties in the exposed sections after ageing, the appearance of cracks caused by humidity variation and UV exposure could lead to weak points on the structure.