首页|混杂钢纤维UHPC拉伸韧性及其评价方法

混杂钢纤维UHPC拉伸韧性及其评价方法

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  • 国家科技期刊平台
  • NETL
  • NSTL
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为研究混杂钢纤维对超高性能混凝土(ultra-high performance concrete,UHPC)拉伸性能的增强、增韧作用,考虑钢纤维的类型、体积掺量和混杂方式等因素,设计并制作8组UHPC狗骨状受拉试件.通过单轴拉伸试验,分析混杂钢纤维UHPC的受拉损伤过程、应力-应变关系曲线、拉伸特征参数和断裂能,提出UHPC拉伸初裂点的量化确定方法,并建立其拉伸韧性的优化评价指标.结果表明:混杂钢纤维UHPC呈现多缝开裂和斜向断裂的韧性破坏特征,拉伸曲线的应变硬化特征明显;短直和端勾钢纤维混杂能显著提升UHPC拉伸应力水平和应变硬化特征,而长直和端勾钢纤维混杂产生的相互作用降低了其拉伸性能;端勾钢纤维的峰前增韧效果显著,1.0％端勾和1.0％短直钢纤维混杂的UHPC,其拉伸韧性达到最高并具有良好的峰前韧性,比单掺2.0％短直钢纤维UHPC提高18.89％～32.56％;长直钢纤维具有稳定、良好的全阶段增韧作用,增大其掺量能提高约30％的UHPC拉伸韧性,但混掺端勾纤维导致的纤维团聚和基体损伤削弱了其增韧作用,UHPC拉伸韧性下降10％以上.基于现有标准和UHPC拉伸韧性评价结果,提出考虑纤维增韧作用和韧性水平的UHPC拉伸性能分级方案,将其分为高增韧型、低增韧型和微增韧型,并给出相应的建议指标.
Tensile toughness of hybrid steel fiber reinforced ultra-high performance concrete (UHPC) and its evaluation method
To investigate the strengthening and toughening effects of hybrid steel fibers on the tensile properties of ultra-high performance concrete(UHPC),eight groups of UHPC dog-bone tensile specimens were designed and manufactured considering the type,volume content and hybrid mode of steel fibers.The tensile damage process,stress-strain curves,tensile characteristic parameters and fracture energy of hybrid steel fiber reinforced UHPC were analyzed by uniaxial tensile tests.Additionally,a quantitative method for determining the initial tensile cracking point of UHPC was proposed based on an analysis of its tensile properties,and optimized indicators for evaluating the tensile toughness of UHPC were further established.The results indicate that hybrid steel fiber reinforced UHPC exhibits the tensile failure modes of multi-crack developing and oblique fracture,and its tensile stress-strain curves display clear strain hardening characteristics.A hybrid of short-straight and hooked-end steel fibers can significantly enhance the tensile stress level and strain-hardening characteristics of UHPC,whereas the interaction of long-straight and hooked-end steel fibers reduces the tensile properties.The highest level of tensile toughness in UHPC is achieved when a blend of 1.0％ hooked-end and 1.0％ short-straight steel fibers is used.This is due to the remarkable pre-peak toughening effect of the hooked-end steel fiber,resulting in excellent pre-peak toughness,which is 18.89％-32.56％ higher than that of UHPC with 2.0％ short-straight steel fiber.Long-straight steel fibers provide a stable and better toughening effect during the entire deformation stage of UHPC.Increasing the content of long-straight fibers can improve the tensile toughness of UHPC by approximately 30％.However,the blending of hooked-end fibers weakens the toughening effect of long-straight fibers due to fiber agglomeration and matrix damage,reducing the tensile toughness of UHPC by more than 10％.Finally,a classification scheme of UHPC tensile properties is proposed considering the fiber toughening and toughness level according to the existing standards and the evaluation results of the UHPC tensile toughness.

ultra-high performance concrete(UHPC)hybrid steel fiberuniaxial tensile testaxial tensile propertyevaluation of tensile toughness

梁林、王秋维、史庆轩

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西安建筑科技大学土木工程学院,陕西西安 710055

超高性能混凝土(UHPC) 混杂钢纤维 单轴拉伸试验 轴拉性能 拉伸韧性评价

国家自然科学基金项目国家自然科学基金项目陕西省教育厅协同创新中心项目

521785055187854323JY043

2024

10.14006/j.jzjgxb.2023.0685

建筑结构学报
中国建筑学会

建筑结构学报

CSTPCD北大核心
影响因子：1.546
ISSN：1000-6869
年,卷(期)：2024.45(9)