尼龙纤维水泥基复合材料的老化性能研究

Weatherability of Nylon Fiber Reinforced Cement Composites

通过人工气候试验和 70°C饱和氢氧化钙溶液浸泡试验 ,对尼龙纤维水泥基复合材料的老化性能进行了研究 .70°C饱和石灰水中浸泡 1 80d以后 ,尼龙纤维水泥砂浆的抗冲击强度表现出快速减小的趋势 ,纤维含量越高 ,减小越明显 .在 3 60d时 ,3种纤维含量砂浆试样的抗冲击强度的差别大大减小 ,抗冲击强度保持率均为 3 0 %左右 .在氙灯人工气候老化条件下 ,尼龙纤维本身发生明显的降解 ,而净浆内部的纤维因为水泥浆对光的屏蔽作用 ,其降解情况显著改善 .老化 40 0h后 ,尼龙纤维水泥砂浆的韧性指数与抗冲击强度的保持率分别可达 82 %～ 87%和 94%～ 99% .

The Weatherability of nylon fiber reinforced cement composites were studied with xenon lamp exposure and immersing in 70 °C saturated calcium hydroxide. The results show that the decrease of impact strength of nylon fiber mortars is accelerated after 180 days immersion. The decrease is markedly enhanced when more fibers were added. After 360 days immersion, the composites remain about 30% of their original strength, there is little difference in impact strengths among three types of mortar with fiber volume content of 0.5%, 1.0% and 1.5%. Under xenon lamp exposure, the IR spectra of nylon fiber showed great change while the IR spectra of nylon fiber in the cement paste had little difference. This indicates the degradation of nylon polymer when it is exposed under UV light, and the cement paste has a shielding effect for nylon fiber. After 400 h exposure, the toughness index measured from flexure test kept 82%～87% of the original value while impact strength kept 94%～99%.