粉煤灰对聚乙烯醇纤维水泥基材料弯曲性能与微观结构影响  

Effects of fly ash content on bending properties and micro structure of polyvinyl alcohol fiber reinforced cementitious composites

作　　者：牛恒茂[1,2] 武文红[3] 李继军[2] 李仙兰[1] 张汉军[1] 

机构地区：[1]内蒙古建筑职业技术学院建筑工程学院,内蒙古呼和浩特010070 [2]内蒙古工业大学理学院,内蒙古呼和浩特010051 [3]内蒙古工业大学信息工程学院,内蒙古呼和浩特010051

出　　处：《混凝土》2016年第12期102-106,共5页Concrete

基　　金：国家自然科学基金项目(11562016);内蒙古自治区高等学校科学研究项目(NJZY330);内蒙古自治区自然科学基金项目(2013MS0107);内蒙古工业大学科学研究项目(X201423)

摘　　要：采用3点弯曲试验,结合宏观裂缝形态与PVA纤维桥接状态,研究了不同粉煤灰掺量下聚乙烯醇纤维水泥基材料(PVA-ECC)的弯曲性能;通过分析试件断裂面处纤维表面、纤维嵌入端和纤维拉断或拔出端的扫描电镜形貌,研究了不同粉煤灰掺量下PVA纤维-基体界面微观结构特征。结果表明:不同粉煤灰掺量下PVA纤维对水泥基材料的增强增韧效果不同,高掺量下增强增韧的效果显著;随粉煤灰掺量增加,基体结构特征更均匀,裂缝处PVA纤维的桥接应力和纤维-基体界面黏结力降低,桥接裂缝的PVA纤维状态由少量纤维短距离滑动拔出转变为大量纤维长距离滑动拔出,纤维桥接裂缝的效率提高,增强增韧的作用增加。Three-point bending test was implemented to evaluate effects of fly ash content on bending properties of polyvinyl alcohol （PVA） fiber reinforced cementitious composites（PVA-ECC） based on crack patterns and PVA fibers morphology in cracks,the mechanism of PVA fiber-reinforced and fiber toughening cementitious composites was analyzed.SEM micrographs of PVA fiber side surface,fibers＇ embedded and ruptured or pullouted ends in fracture surface were investigated to analysis PVA fiber-matrix interface microstructure.Test results find out that PVA fibers play a significantly role on strength and toughness.Moreover, the rate of improvement remarkably increases with more fly ash content.With increasing fly ash content, the eementious matrix characteristic become more uniform, the strength of PVA fibers bridging cracks and interface bonding ability become lower.Meanwhile, the PVA fibers morphology of bridging cracks changes from little PVA fiber short pullouted and slipped to larger number fibers long pullouted and slipped,which significantly improve the rate of fiber-reinforced and fiber toughening and increase bending strength and toughness.

关 键 词：聚乙烯醇纤维 水泥基材料 纤维桥接 纤维增强增韧 界面微观结构 

分 类 号：TU528.041[建筑科学—建筑技术科学]