结构用工程竹抗紫外线老化性能的试验研究

紫外线是导致材料老化的主要因素之一,通过人工加速老化试验,模拟太阳光中的紫外线辐射,加上温湿度循环变化的影响,测试未经防护处理的工程竹的物理力学性能,并与花旗松木材在紫外线辐射下的物理力学性能变化进行对比,评价胶合竹、重组竹、花旗松木材试样的抗紫外线老化性能。结果表明,花旗松木材颜色对紫外线辐射比较敏感,受辐射面有明显的颜色变深,在紫外线辐射下胶合竹也发生颜色变黄但没有花旗松木材严重,重组竹的颜色变化不明显;除顺纹抗压强度胶合竹降幅最大外,顺纹抗压弹性模量、顺纹抗拉强度、抗弯强度、抗弯弹性模量均为花旗松木材降幅最大。总体来说,重组竹的抗紫外线老化性能最优,但胶合竹、重组竹、花旗松木材这三种材料在紫外线辐射作用下均有不同程度的力学性能退化,用于室外环境时需要进行防护处理。

Experimental study on anti-aging performance of engineered bamboo for structural use under UV radiation

UV radiation is one of the main factors that lead to material aging. Through artificial accelerated aging tests, UV radiation in sunlight was simulated, coupled with the influence of temperature and humidity cycles, to test the physical and mechanical properties of unprotected engineered bamboo. The physical and mechanical properties were compared with those of Douglas fir wood under UV radiation, and the anti-aging performance of laminated bamboo, reconsolidated bamboo and Douglas fir wood samples under UV radiation were evaluated. The results show that the wood color of Douglas fir wood is more sensitive to UV radiation, and the radiation surface has obvious color darkening. The laminated bamboo also has yellow color under UV radiation, but the color change of the reconsolidated bamboo is not as obvious as that of Douglas fir wood. In addition to the greatest reduction in grain compressive strength of laminated bamboo, the greatest reduction in grain compressive modulus, grain tensile strength, flexural strength and flexural elastic modulus of Douglas fir wood was found. In general, the recombination bamboo has the best anti-UV aging performance, but the three materials of laminated bamboo, recombination bamboo and Douglas fir wood all have different degrees of mechanical properties degradation under the action of UV radiation, so they need to be protected when used in the outdoor environment.