Drying and heat treatment of bamboo: Cell collapse and restoration

作者：Yeling Xia, Huijun Dong, Kate Semple, Jingda Huang, Wenbiao Zhang, Chunping Dai · 发表于：Construction and Building Materials · 年份：2025 · DOI：10.1016/j.conbuildmat.2025.140314 · 被引用次数：9 · 研究领域：Bamboo properties and applications、Wood Treatment and Properties、Tree Root and Stability Studies

Bamboo is becoming a more competitive supplement material for timber due to its fast growth, high carbon sequestration rate, and superior strength compared to wood. Engineered bamboo manufacturing requires bamboo strips to be first carefully dried, heat treated, and restored for dimensional stability, bond-ability, and durability. This research is an in-depth examination of a typical industrial bamboo strip drying and treatment process at both macro and cellular scales. Unlike lumber, bamboo drying involves five successive lengthy steps: 1) pressurized steam treatment or ‘caramelization’, 2) primary drying, 3) ambient equalization, 4) steam restoration, and 5) secondary drying. Moisture content reduction and equalization take place predominantly during primary drying. In addition to normal shrinkage, low permeability of the thin-walled parenchyma cells with tiny pit connections makes bamboo highly susceptible to cell collapse. The combination of shrinkage and collapse resulted in three patterns of warping in strips: 1) longitudinal bowing, 2) cross-sectional cupping, and 3) differential edge distortion between nodes and internodes. Scanning electron microscopy (SEM) revealed collapse in parenchyma cells, with complex patterns in strip cross-sections governed by the cell locations relative to fiber bundles and inner or outer position in the culm wall. Cell collapse was greatest (43.6 %) near the inner wall, followed by the outer wall (24.1 %) and the middle region (17.3 %). Su...