PVA短纤维增强粉煤灰-地聚合物基挤压复合材料的动态行为

Dynamical behavior of PVA short fiber reinforced fly ashgeopolymeric extrusion composite

首先通过挤压成型技术制备出宽厚比为12.5的聚乙烯醇(PVA)短纤维增强地聚合物基复合材料薄板(SFRGC),然后利用Radmana冲击试验机系统研究了不同纤维体积分数和粉煤灰掺量的SFRGC在高速冲击载荷作用下的力学响应行为。通过激光粒度仪(LSA)、X射线衍射(XRD)、扫描电镜(SEM)等微观测试手段分析了SFRGC的微观结构和冲击破坏机制,结果表明,PVA短纤维的加入改变了地聚合物的冲击破坏模式:由脆性破坏变为延性破坏;对于不掺或掺加少量粉煤灰(≤10 wt%)的地聚合物基复合材料冲击强度高、韧性大,然而当大量粉煤灰(≥30 wt%)加入后,地聚合物基复合材料的冲击强度和韧性显著下降。另外,对SFRGC在20次冻融和1个月硫酸侵蚀作用后的冲击响应进行了研究,探讨了SFRGC在严酷环境条件下的耐久性能。

The polyvinyl alcohol （PVA） short fiber reinforced fly ash -geopolymer composites （SFRGC） （width to height ratio= 12.5） were firstly manufactured by the single-screw extrusion technique. The dynamic responses were studied on the SFRGC with different fiber and fly ash contents by using a Radmana impact tester. The microstructure and impact failure mechanism were also explored by laser particle size analysis （LSA）, X- ray diffraction analysis （XRD） and scanning electron microscope （SEM）. The results show that PVA fiber addition greatly increases the ductility of SFRGC, especially in the ease of high volume fraction of fiber, resulting in a change of impact failure mode from the brittle pattern to a ductile one. A comparative fly ash addition also exhibited obvious influence on the impact behavior. SFRGC without or with low mass fraction of fly ash （≤10%） possess high impact strength, stiffness and toughness. However, the impact resistance is greatly reduced when too much（≥30%） fly ash was incorporated. In addition, the changes in the impact response of SFRGC after subjecting to 20 freeze- thaw cycles and 1 month of H2 SO4 attack were systematically investigated.