摘要
为研究钢纤维-超高性能混凝土(UHPC)基体界面粘结性能的影响因素,进一步阐明不同纤维类型、埋深下双根钢纤维、UHPC基体粘结性能及界面破坏形式,本工作通过双丝拉拔试验对不同埋深的高强钢纤维在UHPC基体中的拔出行为进行研究,以了解纤维的拉拔性能和UHPC的界面粘结性能。纤维拉拔试验以纤维类型及埋深为变量,对两根钢纤维在不同纤维埋深下的评价参数进行了表征和分析,并观察了纤维拔出后的微观形貌和UHPC基体的隧洞形貌。试验结果表明:端钩型纤维的拉拔性能优于直圆型纤维;利用SEM观察到拔出的直圆型纤维表面粘附有絮状或簇状的微小UHPC基体颗粒,并有不同程度的擦伤或长而宽的刮痕,在UHPC基体隧洞中发现了微裂纹,且在纤维拉拔过程中拔出口附近的基体会发生剥落。同时,钢纤维的拉拔性能与纤维埋深有关,但埋深对端钩型纤维影响更大,拉拔荷载峰值达到402.66 MPa,材料的强度利用率为94.9%;纤维的破坏模式也与纤维类型有关,端钩型纤维比直圆型纤维更易发生断裂。本研究可为进一步改善钢纤维增强超高性能混凝土的力学性能提供参考。
In order to study the influence factors of interfacial bond performance between steel fiber and ultra-high performance concrete(UHPC)matrix,to further clarify the failure mode of the bonding interface between two steel fibers and UHPC matrix under different fiber types and embedment depths.Through the double fibers pull-out test,the pull-out behavior of high-strength steel fibers with different buried depths in UHPC matrix was studied to understand the pull-out performance of fibers and the interfacial bonding performance of UHPC.The fiber pull-out test used fiber type and embedment depth as variables to characterize and analyze the evaluation parameters of two steel fibers under different fiber embedment depths,and observed the microscopic morphology of the fibers after pulling out and the tunnel shape of the UHPC matrix.The test results show that the pullout performance of end-hooked fiber is better than that of straight circular fiber;through SEM,it observes that the surface of the pulled straight circular fiber is adhered by floc or cluster of micro UHPC matrix particles,leaving varying degrees of scratches or long and wide scratches.There are microcracks in the UHPC matrix tunnel,and the matrix near the exit of the tunnel is peeled off during the fiber pulled out process.At the same time,the pullout performance of steel fiber was related to the fiber embedment depth,but the embedment depth had a greater impact on the end-hooked fiber,the peak pull-out load reached 402.66 MPa,and the strength utilization rate of the material was 94.9%;the failure mode of fiber was also related to the fiber type.The end-hooked fiber is more prone to fracture than the straight circular fiber.The research of this paper can provide a reference for further improving the mechanical properties of steel fiber reinforced ultra-high performance concrete.
作者
袁明
朱海乐
颜东煌
袁晟
黄练
刘昀
YUAN Ming;ZHU Haile;YAN Donghuang;YUAN Sheng;HUANG Lian;LIU Yun(School of Civil Engineering,Changsha University of Science and Technology,Changsha 410114,China;School of Road and Bridge Engineering,Hunan Communication Polytechnic,Changsha 410132,China)
出处
《材料导报》
CSCD
北大核心
2023年第16期131-139,共9页
Materials Reports
基金
国家自然科学基金项目(52078054,52278141)
湖南省交通科技项目(201932)
湖南省自然科学基金(2021jj30730)
湖南省研究生科研创新项目(CX20200832,CX20190650)。
关键词
桥梁工程
超高性能混凝土(UHPC)
双丝拉拔试验
钢纤维
粘结性能
纤维埋深
bridge engineering
ultra high performance concrete(UHPC)
double fibers pull-out test
steel fiber
bonding properties
fiber embedment depth
