钢-PVA混杂纤维高强机制砂混凝土断裂性能研究  

Study on fracture performances of high⁃strength and manufactured sand concrete added with steel and PVA fibres

作　　者：栗帅武 丁德鹏 何少华 卢俊蓉 熊哲[2] 武念铎 LI Shuaiwu;DING Depeng;HE Shaohua;LU Junrong;XIONG Zhe;WU Nianduo(China Railway 17th Bureau Group(Guangzhou)Construction Co.,Ltd.,Guangzhou 510663,China;School of Civil and Transportation Engineering,Guangdong University of Technology,Guangzhou 510006,China;China Construction Eighth Engineering Division Co.,Ltd.,Shanghai 200135,China)

机构地区：[1]中铁十七局集团(广州)建设有限公司,广州510663 [2]广东工业大学土木与交通工程学院,广州510006 [3]中国建筑第八工程局有限公司,上海200135

出　　处：《建筑结构》2025年第5期47-54,共8页Building Structure

基　　金：广东省自然科学基金-杰出青年项目(2024B1515020028)。

摘　　要：依托黄埔区科学城连接知识城快速通道(南段)工程钢箱梁顶面钢纤维混凝土叠合层施工项目,研究钢纤维和聚乙烯醇(PVA)纤维的混合使用对提升高强机制砂混凝土抵抗裂缝发展的作用。对预制裂缝梁进行三点弯曲加载试验,探究机制砂替代率、PVA纤维掺量对高强机制砂混凝土断裂性能的影响。结果表明:过大机制砂替代率使得试件在裂缝的发展过程中出现次生裂缝,而PVA纤维协助混凝土抗拉从而抵抗裂缝发展;50%以下的机制砂替代率可以提高试件荷载-跨中挠度曲线的峰值荷载,而PVA纤维掺量的增大会使曲线下降段变得平缓;随着机制砂替代率的增大,混凝土断裂能、起裂韧度以及失稳断裂韧度均呈先增大后减小的趋势;当PVA纤维掺量在0%~0.3%范围内增大,断裂能、起裂韧度以及失稳断裂韧度随之增大;当机制砂替代率和PVA纤维掺量分别为50%、0.3%时,断裂能、起裂韧度以及失稳断裂韧度达到最大值,相较未添加机制砂和PVA纤维的情形,断裂能、起裂韧度以及失稳断裂韧度分别提高70.03%、68.79%、154.88%。Based on the construction project of the steel fiber reinforced concrete composite layer on the top surface of the steel box girder of the Huangpu District Science City Connection Knowledge City Expressway(south section),the effects of the mixed⁃use of steel and polyvinyl alcohol(PVA)fibres on enhancing the ability of high⁃strength and manufactured sand concrete to resist crack development were studied.Three⁃point bending tests for prefabricated cracked beams were applied to investigate the effects of replacing ratio of manufactured sand and PVA fibres content on the fracture performances of high⁃strength and manufactured sand concrete.The results show that excessive relacing ratio of manufactured sands makes the specimen appear secondary cracks in the process of crack development,while the PVA fibres help concrete bear the tensile stress so as to resist the crack development.The relacing ratio of manufactured sands less than 50%improve the maximum load of the load⁃mid span deflection curves of the specimen,while the increase of the PVA fibre contents make the descending section of the curve gentle.With the increase of relacing ratio of manufactured sands,the fracture energy,initial toughness and unstable fracture toughness of concrete firstly increase and then decrease.When the PVA fibre content increase from 0%to 0.3%,the fracture energy,initial toughness and unstable fracture toughness increase.When the replacing ratio of manufactured sand is 50%and PVA fibre content is 0.3%,the fracture energy,initial toughness and unstable fracture toughness reach the maximum;compared to the concrete without manufactured sands and PVA fibres,the fracture energy,initial toughness and unstable fracture toughness are improved by 70.03%,68.79%and 154.88%,respectively.

关 键 词：钢纤维 PVA纤维 机制砂混凝土 断裂能 断裂韧度 

分 类 号：TU528[建筑科学—建筑技术科学]