龙竹竹材的吸水膨胀特性

A study on the character of water-absorption and expansion of Dendrocalamus gigangteus timber

对未处理、水煮处理和汽蒸处理的龙竹竹材的吸水膨胀特性进行了测试和分析,以了解处理方式对竹材吸水膨胀性能的影响。结果表明:不同处理后的竹材各个方向上吸水膨胀特性差异显著,且竹间部位和竹节部位的吸水膨胀特性也有一定差异。相同处理时,竹间试件吸水速度大于竹节试件,水煮处理竹间试件吸水速度大于汽蒸竹间试件和未处理竹间试件;水煮试件吸水膨胀率大于汽蒸试件和未处理试件。竹间试件弦向吸水膨胀率大于竹节弦向吸水膨胀率,竹间径向吸水膨胀率大于竹节径向吸水膨胀率。纵向产生吸水尺寸缩小现象,可能是泊松效应,此现象有待进一步试验和分析。

The impact of different treatment on the characters of water-absorption and expansion of bamboo timber was studied based on the determination and analysis of no treatment, water cooked treatment and steam treatment. The result showed that the difference of water-absorption and expansion of bamboo timber among three directions was distinct, and there was definite difference between the knot section and knotless section. The water-absorption rate of knotless section sample was faster than that of knot section sample in the same conditions. The water-asorption rate of knotless section sample cooked in water was faster than that of others. The expansion rate of the water-cooked bamboo sample was the highest in all samples. Both tangential water-absorption and expansion rate and radial direction of the knotless section sample were higher than that of the knot section samples. The phenomenon of reducing in the long direction took place maybe because of the Poisson effect. The phenomenon needs to be further studied.