Study on shrinkage and rheological behavior induced by water migration during the conventional kiln drying process of moso bamboo strips

Bamboo, fast-growing and resource-rich, can replace wood, but drying-induced deformation and cracking hinder processing due to stress from moisture migration. Studying its drying stress–strain behaviour is key for drying techniques. This study examined bamboo strips’ moisture content (MC), shrinkage, and rheology at 45°C and 85°C during drying. Key findings include: Higher temperatures lead to a faster bamboo-drying rate but a more uneven MC distribution. Bamboo strips shrink at high MC, with radial shrinkage about twice the tangential one. Viscoelastic and mechano-sorptive creep strains (MSCS) are small at 45°C and larger/variable at 85°C. MSCS, the main cause of permanent deformation, exceeds viscoelastic creep. Bamboo warpage rises with temperature (0.5% at 45°C, 1.6% at 85°C). Temperature significantly affects drying stress–strain development, so low-temperature drying is better for control. Gradually increasing temperature and reducing humidity is recommended to prevent warping and cracking.