粉煤灰—地聚合物水泥基挤压复合材料的制备及其动态性能

利用自行研制的活塞式挤压流变仪研究了掺加PVA短纤维和粉煤灰的地聚合物浆体在挤压过程中的流变学特性,在此基础上通过单轴挤压机成功制备出宽厚比为12.5的短纤维增强地聚合物基复合材料薄板.利用Rdmana冲击试验机系统分析了各种纤维和粉煤灰掺量的地聚合物挤压板在冲击载荷作用下的力学响应行为.结果表明,PVA短纤维的加入改变了粉煤灰基地聚合物材料破坏模式:由脆性破坏变为延性破坏,使纤维的加入明显提高了粉煤灰基地聚合物材料的冲击韧性.对于不掺或掺加少量粉煤灰的地聚合物材料具有较高的冲击强度、刚度和韧性.当太多量的粉煤灰被加入后,粉煤灰基地聚合物复合材料薄板的抗冲击性能显著下降.通过扫描电镜(SEM)、X衍射(XRD)、激光粒度仪(LSA)等微观测试手段探讨了SFRGC的微观结构和冲击破坏机理.

Preparation and dynamical behavior of fly ash based geopoymeric cement extrudated composite

The effect s o f f ly ash and fiber on the rheo logical behaviors of geopo lymeric pastes were systematical ly invest igated by using the special ly designed ram rheometer. Based on the r heolog ical test ing result s, a PVA sho rt fiber reinforced f ly ash-g eo polymer composites manufactured by ext rusion technique ( SFRFGC) was successfully prepared by adjusting the fiber vo lume fr act ion and fly ash content . The dymanic behavior s were then studied on the SFRFGC by using Rdmana impact tester . T he ex perimental result s show that for no rmally curing SFRGC, PVA fiber addit ion great ly increases the ductility o f SFRGC, especially in the case of hig h v olume fraction of fiber, result ing in a change of impact failure mo de from britt le pat tern to duct ile one. As a r esult , a great increase in the impact to ug hness w as seen in SFRGCw ith high f iber content . Comparatively fly ash addition also exhibit s obvious influence on the r helog ical and impact behaviors. T he spherical shape of f ly ash part icles can g reatly improv e the ext rudabil ity of fr esh SFRGC pastes. SFRGC w ithout or w ith low per centage of f ly ash possesses very hig h impact st rength and st iffness. How ev er , w hen to o much f ly ash is incorporated, the impact resistance o f SFRGC is reduced rapidly . The cor respo nding micro st ructure and failur e mechanism ar e also explored by laser particle size analy sis ( LSA) , X-ray dif fr act io n analy sis ( XRD) , and scanning elect ron microsco pe ( SEM) .