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刘   波¹ , 周   政¹ ,  张   理² ,  于   琳³

 

( 1. 西安市市政设施管理中心 , 西安   710016 ;  2.  西安市东郊市政设施养护管理有限公司 ,  西安   710000 ;

3. 石家庄市排水管护中心 , 石家庄   050000)

摘  要 :  为提升市政桥梁超高性能混凝土  ( UHPC)  的韧性 ,  借助室内试验的方法 ,  设计了 16 组不同钢 - PVA 混杂纤维的 UHPC 配合比 , 制备试件并开展中心拉拔试验与四点弯曲试验 , 获取其黏结应力-滑移曲线与荷载-挠度曲线 , 分析纤维的协同增强机理 。结果表明 : 混杂纤维能显著改善 UHPC 的界面性能与构件力学行为 ;混杂纤维最优配比为 2. 5%钢纤维+ 1. 5%PVA 纤维 ; 混杂纤维最优配比时 , 黏结强度峰值为 42. 7 MPa , 滑移峰值为 0. 78 mm , 相比于素 UHPC 增幅分别达 49. 8% 、550% , 破坏模式转变为高延性破坏 ; 混杂纤维最优配比时 ,试件极限抗弯承载力达到 119. 9 kN ,  相较素 UHPC 提升 52. 2% , 极限挠度达 24. 8 mm ,  为素 UHPC 梁的 4 倍 , 耗能能力约为素 UHPC 梁的 3. 8 倍 。研究成果明确了钢-PVA 混杂纤维对 UHPC 综合性能的改善效应及最优纤维掺量范围 , 可为该材料在桥梁关键受力部位的应用提供试验依据。

关键词 : 超高性能混凝土 ; 混杂纤维 ; 黏结性能 ; 抗弯性能 ; PVA ; 钢纤维

中图分类号 : TU528           文献标志码 : A           文章编号 :  1005- 8249  (2026)  03-0044-07

DOI :10. 19860/j. cnki. issn1005- 8249. 2026. 03. 008

 

LIU Bo¹ , ZHOU Zheng¹ , ZHANG Li² , YU Lin³

( 1. Xi ’an Municipal Facilities Management Center , Xi ’an 710016 , China;

2. Xi ’an Dongjiao Municipal Facilities Maintenance and Management Co. , Ltd. , Xi ’an 710000 , China;

3. Shijiazhuang Drainage Pipeline Maintenance Center , Shijiazhuang 050000 , China)

Abstract :  To enhance the toughness of ultra-high performance concrete  ( UHPC)  for  municipal bridges , 16 groups of UHPC mix proportions with  different  steel - PVA hybrid fibers were  designed  using  indoor testing  methods.    Test   specimens  were prepared and subjected to center pull-out tests and four -point bending tests to obtain their bond stress - slip curves and load - deflection curves , and the synergistic reinforcement mechanism of the fibers was analyzed.   The results showed that hybrid fibers significantly improved the interfacial properties and mechanical behavior of UHPC components.   The optimal proportion of hybrid fibers was 2. 5% steel fibers +  1. 5% PVA fibers.   At this optimal proportion , the peak bond strength reached 42. 7 MPa and the peak slip was 0. 78 mm , representing an increase of 49. 8%  and 550% respectively compared to plain UHPC.   The failure mode transitioned to high ductility failure.   At this optimal proportion of hybrid fibers , the ultimate flexural bearing capacity of the test  specimens reached 119. 9 kN ,  an  increase  of  52. 2%  compared  to  plain  UHPC.    The  ultimate  deflection  reached  24. 8 mm , which was four times that of plain UHPC beams , and the energy dissipation capacity was approximately 3. 8 times that of plain UHPC  beams.    The  research  results  clarified  the  improvement  effect  of  steel - PVA   hybrid  fibers  on  the  comprehensive performance of UHPC and the optimal fiber content range , providing experimental evidence for the application of this material in key load-bearing parts of bridges.

Key words :  UHPC ; hybrid fibers ; bond characteristics ; flexural performance ; PVA; steel fiber