摘要
将细短钢纤维定向分布在水泥浆中制备超高性能混凝土(UHPC),在不同的钢纤维体积掺量下,对比分析了定向分布钢纤维UHPC(D-UHPC)与乱向分布钢纤维UHPC(L-UHPC)的抗压、抗折和弯曲抗拉等强度,通过弯曲韧性、钢纤维与UHPC基体的界面黏结强度及宏观、细观照片来揭示其增强作用机理。结果表明:随着钢纤维掺量的增加,L-UHPC的抗压强度先增大后减小,D-UHPC的抗压强度则持续增大;两种UHPC的抗折强度均随着钢纤维体积掺量的增加而不断增大;在相同的钢纤维体积掺量下,D-UHPC的抗折强度均比L-UHPC的更高;试样受弯断裂过程中,D-UHPC所产生的裂缝宽度比L-UHPC的更窄,且出现了更多细小裂缝,可通过分散吸收荷载而表现出更高的弯曲韧性;D-UHPC的初裂挠度、极限抗拉挠度、初裂强度、极限抗拉强度和韧性指数在相同的钢纤维体积掺量时均比L-UHPC的有大幅度增加;钢纤维的埋入角越大,拔出荷载峰值越小,且荷载峰值对应的挠度越大,显示出钢纤维方向对UHPC力学性能的显著影响。
Fine and short steel fiber was orientally distributed in the paste to prepare a ultra-high performance concrete(UHPC). The compressive strength, flexural strength, flexural tensile strength, and the interfacial bonding strength between steel fiber and UHPC matrix of the directionally distributed steel fiber UHPC(D-UHPC) and the disorderly distributed steel fiber UHPC(L-UHPC) at different volume contents of steel fiber were analyzed. The results demonstrate that the compressive strength of L-UHPC firstly increases and then decreases, and the compressive strength of D-UHPC continues to increase as the volume content of steel fiber increases. The flexural strength of both types of UHPCs improves with the increase of the volume content of steel fiber. At the same volume content of steel fiber, the flexural strength of D-UHPC is greater than that of L-UHPC. In the tensile fracture of the specimen, the crack width produced by D-UHPC is narrower than that of L-UHPC, and D-UHPC has more small cracks by dispersing and absorbing loads. The initial cracking deflection, ultimate tensile deflection, initial cracking strength, ultimate tensile strength, and toughness index of D-UHPC all increase, compared to that of L-UHPC at the same volume content of steel fiber. Increasing the embedding angle of the steel fiber decreases the peak value of the pull-out load and increases the deflection corresponding to the peak value of the load, thus indicating that the direction of the steel fiber affects the mechanical properties of UHPC.
作者
苟鸿翔
朱洪波
周海云
杨正宏
GOU Hongxiang;ZHU Hongbo;ZHOU Haiyun;YANG Zhenghong(Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education,Tongji University,Shanghai 201804,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2020年第11期1756-1764,共9页
Journal of The Chinese Ceramic Society
基金
国家“十三五重点研发计划”(2018YFC0705400,2018YFD1101002)。
关键词
钢纤维
定向分布
超高性能混凝土
力学性能
细观分析
steel fiber
orientation distribution
ultra-high performance concrete
mechanical properties
mesoscopic analysis
作者简介
第一作者:苟鸿翔(1995-),男,硕士研究生;通信作者:朱洪波(1965-),男,博士,副教授。
