聚合物纤维对水泥砂浆流动性及抗弯力学性能的影响  

Effects of polymer fibers on the flowability and bending performance of mortars

作　　者：刘辉[1,2] 孔祥明[1] 张珍林[1] 蒋凌飞[1] 徐涛[1] 王栋民[2] 

机构地区：[1]清华大学土木系土木工程安全与耐久教育部重点实验室,北京100084 [2]中国矿业大学(北京)化学与环境工程学院化学系,北京100083

出　　处：《混凝土》2014年第2期121-124,共4页Concrete

摘　　要：研究了四类聚合物纤维(超高分子量聚乙烯(UPE)纤维、聚丙烯(PP)纤维、聚乙烯醇(PVA)纤维、聚丙烯腈(PAN)纤维),对水泥砂浆流动性及抗弯力学性能的影响。结果表明:四种纤维都对砂浆的流动性产生不利影响,PAN纤维对砂浆流动性影响最显著。四种纤维对砂浆的三点抗弯力学性能产生不同程度的影响。在荷载作用下,掺加纤维使砂浆的破坏由单裂缝增长的脆性断裂转变为多点开裂。UPE纤维对砂浆力学增韧效果最为显著,纤维掺量为0.5%时,产生明显的应变硬化特征,提高了砂浆的韧性;PP纤维虽然拉伸强度和弹性模量比较低,但掺量0.5%时也可明显提高砂浆的延性。对比两种不同长径比的PVA纤维,测试结果表明,长且细的PVA纤维对扩展度的负面影响更显著,对砂浆的延性和韧性贡献更小。Four types of polymer fibers（ultra-high molecular weight polyethylene,UPE;polypropylene,PP;polyvinyl alcohol,PVA;polyacrylonitrile,PAN） were added into cement mortars to study their influences on the flowability and bending performance of mortars. Results showed that the four fibers had negative impact on the flow table spread ,among which PAN fiber led to the lowest flow table spread at the same dosage.Fiber reinforced mortars present multiple cracking feature under bending load while neat mortars exhibit brittle failure.UPE fiber modified mortars present strain hardening performance at low dosage ,which provided the mortars a better ductility under bending load.In spite of resulting in lowered elastic modulus and tensile strength of mortars ,PP fibers have positive impact on mechanical performance of mortars at high dosage （0.5%by volume） in terms of stress hardening characteristics,elongation at break etc.Comparison be-tween PVA fibers with different length-diameter ratios showed that the shorter and thinner PVA fiber has more pronounced negative ef-fects on the flow ability and mechanical properties of the modified mortars.

关 键 词：聚合物纤维 纤维增强砂浆 流动性 力学性能 

分 类 号：TU528.041[建筑科学—建筑技术科学]