新型混杂纤维UHPC双向板弯曲韧性研究  

Flexural toughness of two-way slabs of UHPC with new hybrid fibers

作　　者：于跟社 邓宗才[2] YU Genshe;DENG Zongcai(School of Civil Engineering,Central South University,Changsha 410075,China;College of Architecture and Civil Engineering,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]北京工业大学建筑工程学院,北京100124

出　　处：《哈尔滨工程大学学报》2025年第2期219-226,233,共9页Journal of Harbin Engineering University

基　　金：北京市教委科技重点项目(KZ201810005008)。

摘　　要：为研究混杂纤维对超高性能混凝土板弯曲性能的影响,本文开展了混杂纤维超高性能混凝土方板弯曲试验。试验共设计7组尺寸为500 mm×500 mm×50 mm的方板试件,其中单掺钢纤维1组,钢纤维分别与2种长径比粗聚烯烃纤维混掺2组、与2种长径比粗聚乙烯醇纤维混掺2组,与2种长径比粗聚酯纤维混掺2组。测定了各组板试件的荷载-挠度曲线、初裂荷载和峰值荷载,计算并分析了双向板的裂后弯曲韧性指标和能量吸收值等。结果表明:板的破坏经历了弹性阶段、强化阶段和软化阶段;混杂纤维超高性能混凝土板变形曲线具有明显的硬化特征;与单掺钢纤维比较,混杂纤维有利于提高板峰值荷载和裂后弯曲韧性;混掺长径比较大的粗合成纤维有利于改善板强化阶段和软化阶段力学性能,特别是显著改善了板的裂后韧性和耗能能力;粗聚酯纤维的直径不宜大于0.75 mm。To investigate the contribution of hybrid fibers to the bending performance of ultra-high performance concrete(UHPC)slabs,bending tests were conducted on hybrid fiber-reinforced UHPC square slabs.Seven groups of square slab specimens(500 mm×500 mm×50 mm)were designed:one group containing only steel fibers(SF),two groups with SF mixed with macro-polyolefin fibers of two different large aspect ratios,two groups with SF mixed with macro-polyvinyl alcohol fibers of two different large aspect ratios,and two groups with SF mixed with macro-polyethylene(PET)fibers of two different large aspect ratios.The load-deflection curves,initial cracking loads,and peak loads of each group of specimens were measured,and the bending toughness indexes and energy dissipation capacities were calculated and analyzed.The results indicated that the damage to the slabs progressed through three stages:elastic,strengthening,and softening.The deformation curves of the hybrid fiber-reinforced UHPC slabs exhibited notable hardening characteristics.Compared with slabs with only SF,the hybrid fiber-reinforced UHPC slabs demonstrated improved peak loads and bending toughness after cracking.In addition,mixing coarse synthetic fibers with larger aspect ratios enhanced the mechanical properties during the strengthening stage and softening stages of the slabs.Especially,the postcrack toughness and energy dissipation capacity were significantly improved.Furthermore,the diameter of the PET fibers should not exceed 0.75 mm.

关 键 词：UHPC 混杂纤维 弯曲韧性 能量 韧性指标 双向板 弯曲 力学性能 

分 类 号：TU528.572[建筑科学—建筑技术科学]