摘要
提出纳米-微米-毫米多尺度纤维复合增强超高性能混凝土(UHPC)的思路,利用不同尺度的纤维抑制不同尺度缺陷,整体提升UHPC的力学性能。通过掺加纳米尺度的碳纳米管、微米尺度的碳酸钙晶须和毫米尺度的钢纤维,设计了7组不同纤维掺杂的UHPC试件,测试了UHPC的轴心抗拉和轴心抗压应力-应变曲线。结果表明:宏观尺度的毫米钢纤维决定了UHPC试件的初裂强度和初裂应变,微观尺度的微米纤维和纳米纤维对初裂强度和初裂应变影响不大;但碳酸钙晶须和碳纳米管的加入,改变了UHPC试件开裂后的拉伸行为,显著增强了其应变硬化能力。不同尺度纤维对UHPC轴心抗拉和抗压性能都表现出类似的规律:与钢纤维复掺时,碳酸钙晶须的效果优于碳纳米管的效果,且碳酸钙晶须和碳纳米管两者同时掺加效果最好。
A nano-, micron-, and millimeter-sized multi-scale fiber composite reinforced ultra-high performance concrete(UHPC) was proposed. The mechanical properties of UHPC can be improved by suppressing the defects of different sizes with different fibers. Carbon nanotubes, micron-sized calcium carbonate whiskers, and millimeter-sized steel fibers were used to design 7 groups of UHPC specimens. The axial tensile and compressive stress-strain curves of UHPC were measured. The results show that the initial crack strength and strain of UHPC are determined by the millimeter-sized steel fiber in a macro-scale. However, micron-and nano-sized fibers have little effect on the initial crack strength and strain. The addition of calcium carbonate whiskers and carbon nanotubes changes the tensile behavior of UHPC specimens after cracking, thus enhancing the strain hardening capability. The tensile and compressive properties of UHPC with different sizes of fibers are similar. The addition of calcium carbonate whisker has a positive effect rather than that of carbon nanotube when mixing with steel fiber. The effect becomes optimum when adding calcium carbonate whiskers and carbon nanotubes.
作者
张文华
张仔祥
刘鹏宇
张云升
张春晓
佘伟
ZHANG Wenhua;ZHANG Zixiang;LIU Pengyu;ZHANG Yunsheng;ZHANG Chunxiao;SHE Wei(Department of Civil Engineering,Nanjing Forestry University,Nanjing 210037,China;Department of Materials Science and Engineering,Southeast University,Nanjing 211189,China;College of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;National Defense Engineering Institute,Academy of Military Science of PLA,Luoyang 471023,Henan,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2020年第8期1155-1167,共13页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金面上项目(51678309,51978339)
硅酸盐建筑材料国家重点实验室(武汉理工大学)开放基金资助
江苏高校优势学科建设工程资助项目(PAPD)。
关键词
超高性能混凝土
多尺度
纤维
碳酸钙晶须
碳纳米管
ultra-high performance concrete
multi-scale
fiber
calcium carbonate whisker
carbon nanotubes
