PVA纤维混凝土弯折试验研究  

Experiments on bending of PVA fiber concrete beams

作　　者：彭定超[1] 袁勇[2] 

机构地区：[1]上海现代建筑设计集团有限公司都市建筑设计研究院,上海200002 [2]上海同济大学地下建筑与工程,上海200092

出　　处：《混凝土》2004年第1期46-51,共6页Concrete

摘　　要：　混凝土的脆性以及抗裂性能很差,在其中掺入合成纤维成为增加韧性、提高早期和极限抗拉强度以及改善诸如梁柱节点等重要部位的抗震性能的一种很重要的方法;作为合成纤维中的一种,新型的聚乙烯醇(PVA)纤维还具有高强高模的特性,能否兼有合成纤维与高弹性模量纤维的优点,是本文研究的重点。本文从增加混凝土韧性、提高混凝土抗拉强度的观点出发,对PVA纤维混凝土进行了6种纤维体积含量(0 00%、0 05%、0 15%、0 30%、0 50%、1 00%)、4种龄期(3天、7天、14天、28天)的标准四点弯曲试验,试验结果表明:无论哪种龄期,PVA纤维混凝土梁的韧性要比普通混凝土梁高,提高幅度基本随纤维含量的增加而增大;初期抗拉强度与极限抗拉强度在体积掺量超过0 5%后均有明显增加,小于此含量时,变化规律不很明显。无论哪种纤维含量,混凝土梁的韧性随龄期变化规律不是很明显;初期抗拉强度与极限抗拉强度在早龄期(3天)就达到相应最终强度(28天)的85%以上,并随龄期的增加而有所提高,但变化规律不很明显。The concrete is a kind of brittle material and has poor crack resistance.With joining synthetic fiber into concrete,the toughness improves,and early tensile strength and utmost tensile strength enhance.The toughness of some important portions just like concrete frame joints enhance too under seismic load.So joining synthetic fiber into concrete is a good method changing the concrete into a kind of ductility material.As a sort of synthetic fiber,the Polyvinyl Alcohol Fiber(PVA) is kind of high strength and high modulus fiber too.Whether the PVA fiber holds the merits of synthetic fiber and high modulus fiber or not,this is a research facet in the paper.In ordering to enhancing toughness of concrete, and improving tensile strength of concrete,this paper studies a lot of PVA fiber concrete beams by standard four-points bending,and the beams have six kinds of fiber volume ratios including 0.00%、0.05%、0.15%、0.30%、0.50%、1.00% and four kinds of concrete ages including 3^(th) days、 7^(th) days、14^(th) days、28^(th)days.The results indicate that in all ages the toughness of PVA fiber concrete beams is higher than ordinary concrete beams',and the enhancing extent is improving with fiber volume ratio's improving basically,but the rule is not obviously.The cracking tensile strength and the utmost tensile strength are obviously enhancing with the fiber ratio over 0.5%,and below 0.5% the rule is not obvious.In all fiber volume ratios,the toughness of concrete beams including fiber concrete ones and ordinary ones change (without) obvious rule with the changing of ages.The cracking tesile strength and the utmost tensile strength under early age(3^(th) days) are almost not less than the 85% of ones under 28^(th) days,and increasing more or less with the increasing of ages,but the rule is not obvious.

关 键 词：PVA纤维混凝土 四点弯曲试验 早期强度 抗拉强度 韧性 抗震性能 聚乙烯醇 

分 类 号：TU528.572[建筑科学—建筑技术科学]