超高性能钢纤维增强混凝土抗拉性能试验研究  

Experimental study on tensile properties of ultra-high performance steel fiber reinforced concrete

作　　者：杨小钰[1] 王尧[2] YANG Xiaoyu;WANG Yao(Shanxi Technology and Business College,Taiyuan 030032,China;Shanxi Water Resources&Hydropower Surveying and Designing Institute,Taiyuan 030024,China)

机构地区：[1]山西工商学院南校区,山西太原030032 [2]山西省水利水电勘测设计研究院有限公司,山西太原030024

出　　处：《混凝土》2022年第6期98-102,共5页Concrete

摘　　要：由于超高性能混凝土(UHPC)抗拉、抗压强度的不均匀性,在基体中添加微钢纤维可以改善混凝土的抗拉性能,提高拉压比。考虑到UHPC在使用过程中会受动态荷载的作用,采用直径20 mm的分离式霍普金森压杆(SHPB)装置,对UHPC在高应变率下的力学响应行为进行了研究。结合扫描电子显微镜(SEM)技术来探讨低速和高速加载时试件的失效机理。结果表明,在拉伸过程中,微钢纤维的加入可使抗拉强度提高2倍左右。UHPC动态抗拉强度和动态强度增加因子(DIF)均随应力速率的增加而增加,表现出明显的率效应。与不含微钢纤维的对照组相比,包含微钢纤维试件的动态增加因子(DIF)更低,率敏感性也较低,UHPC基体中的微钢纤维防止了试件的劈裂破坏,并在峰值应力后保持了试件的结构完整性。含有微钢纤维的UHPC试件在低速和高速冲击下表现出不同的损伤模式。Due to the non-uniform tension and compression strength of ultra-high performance concrete,micro-steel fibers can be added to concrete to improve its static tensile behavior and increase the tension-compression ratio.In view of the UHPC will be subjected to dynamic loads during operation,a 20 mm diameter split Hopkinson pressure bar(SHPB)was used to study the mechanical response of UHPC at high strain rates.Scanning electron microscopy(SEM)was used to investigate the failure mechanism of specimens under low speed and high speed loading.The results show that the addition of micro-steel fibers can increase the tensile strength by about two times.The UHPC dynamic tensile strength and dynamic strength increasing factor(DIF)both increased with the increase of stress rate,showing obvious rate effect.Compared with the control group without micro-steel fibers,the dynamic increasing factor(DIF)and rate sensitivity of UHPC specimens containing micro-steel fibers were lower.The micro-steel fibers in the UHPC matrix prevented the splitting failure of the specimen and kept the structural integrity of the specimen after the peak stress.The UHPC specimens containing micro-steel fibers exhibit different damage modes at low speed and high speed.

关 键 词：微钢纤维 SHPB 抗拉性能 DIF UHPC 

分 类 号：TU528.041[建筑科学—建筑技术科学]