混杂纤维混凝土带切口梁的跨中挠度与裂缝口张开位移研究  

Research on mid-span deflection and CMOD of hybrid fiber reinforced concrete notched beam

作　　者：夏冬桃[1] 吴伟波[1] 熊思慧 Xia Dongtao Wu Weibo Xiong Sihui(Civil Engineering and Building Academy, Hubei University of Technology, Wuhan 430068, Chin)

机构地区：[1]湖北工业大学土木工程与建筑学院,湖北武汉430068

出　　处：《建筑科学》2017年第7期40-44,51,共6页Building Science

基　　金：国家自然科学基金"挠度和裂缝宽度双参控制的混杂纤维混凝土韧性评定方法"(51108164)

摘　　要：选用总体积掺量不超过1%的钢纤维(SF)、塑钢纤维(MPF)和聚丙烯单丝纤维(PF),进行混杂纤维混凝土带切口梁三点弯曲试验,通过荷载-挠度曲线分析了纤维混杂方式和掺量对混凝土弯曲韧性的影响,对裂缝口张开位移-挠度曲线进行线性拟合,初步探究了基于荷载-裂缝口张开位移曲线的弯曲韧性评价方法。研究结果表明:三元混杂纤维增强混凝土具有较素混凝土、单掺及二元混杂纤维混凝土更优的弯曲韧性,基于弯曲韧性的最优混杂组合为0.7%SF、0.19%MPF、0.11%PF;跨中挠度δ与裂缝口张开位移呈较好的双折线关系,由基于荷载-挠度曲线的弯曲韧性评价方法得出的结论,与由基于荷载-裂缝口张开位移曲线的弯曲韧性评价方法得出的结论一致,通过荷载-裂缝口张开位移曲线对混杂纤维混凝土的弯曲韧性进行评价是可行的。The three-point bending test on notched beam is carried out to study on the mid-span deflection and crack mouth opening displacement（ CMOD）. Steel fiber（ SF）,modified polypropylene fiber（ MPF） and polypropylene fiber（ PF） are chosen to be reinforced in concrete with the total volume fraction not more than 1%.The effect of hybrid mode and volume fraction on flexural toughness of concrete is analyzed through the loaddeflection curves. The CMOD-deflection curves are linear fitted to investigate the evaluation method of flexural toughness preliminarily based on the load-CMOD curves. The results indicate that,compared with the matrix concrete,simplex or binary hybrid fiber reinforced concrete,the ternary hybrid fiber reinforced concrete in an appropriate combination has a better flexural toughness,and the optimal combination is 0. 7% SF,0. 19% MPF and0. 11% PF; the relationship between mid-span deflection and CMOD is bilinear form; the conclusion of the evaluation method of flexural toughness based on the load-CMOD curves is the same as that based on the loaddeflection curves. Therefore,the evaluation method of flexural toughness based on the load-CMOD curves is feasible.

关 键 词：混杂纤维 带切口梁 跨中挠度 裂缝口张开位移 弯曲韧性 

分 类 号：TU528.572[建筑科学—建筑技术科学]