摘要
为探究碳纤维增强作用对混凝土材料抗疲劳性能的影响规律,利用电液伺服压力机对4种(不掺、碳纤维、碳纤维布、碳纤维+纤维布)混凝土开展不同次数(0次、20次、40次、60次、80次、100次)循环加卸载疲劳致损,对疲劳损伤试件纵波波速及力学性能开展试验研究。结果表明:(1)随着循环加卸载次数的增加,4种混凝土试件纵波波速均呈降低趋势,其中素混凝土试件呈二次函数降低,其余试件均呈线性函数降低;(2)相较于素混凝土,碳纤维混凝土、碳纤维布混凝土、碳纤维+纤维布混凝土峰值应力增幅分别为18.60%、39.33%、64.33%,碳纤维、碳纤维布的使用均能增强混凝土材料抗外荷载、抗变形能力。循环加卸载次数的增加使得4种混凝土试件峰值应力均呈线性降低;(3)相较于未循环加卸载试件,循环加卸载20次、40次、60次、80次、100次时,碳纤维布混凝土弹性能降幅为4.43%、8.88%、12.36%、20.43%、25.26%,循环加卸载作用对试件造成疲劳损伤,从而降低混凝土材料的储能效果,对其造成不可逆的损伤破坏;(4)素混凝土、碳纤维混凝土、碳纤维布混凝土、碳纤维+纤维布混凝土对应突变点应变分别为0.64%、1.05%、1.00%、1.68%,纤维及纤维布的使用均使得混凝土试件突变点应变增加,纤维的使用能够增强混凝土材料的延展性,循环加卸载作用降低了试件的延性。
In order to explore the effect of fiber reinforcement on the fatigue resistance of concrete materials,the electro-hydraulic servo press was used to carry out fatigue damage caused by different times(0,20,40,60,80,100)of four kinds of concrete(plain,carbon fiber,carbon fiber cloth,carbon fiber and fiber cloth).The longitudinal wave velocity and mechanical properties of fatigue damaged specimens were investigated experimentally.The results show that:(1)With the increase of cyclic loading and unloading times,the longitudinal wave velocity of the four concrete specimens showed a decreasing trend,in which the plain concrete specimens showed a quadratic function decrease,and the other specimens showed a linear function decrease.(2)Compared with plain concrete,the increase of peak stress of carbon fiber concrete,carbon fiber cloth concrete,carbon fiber and fiber cloth concrete is 18.60%,39.33%and 64.33%,respectively.The use of carbon fiber and carbon fiber cloth can enhance the external load resistance and deformation resistance of concrete materials.The peak stress of four kinds of concrete specimens decreased linearly with the increase of cyclic loading and unloading times.(3)Compared with non-cyclic loading and unloading specimens,when cyclic loading and unloading were performed for 20,40,60,80 and 100 times,the elastic energy of CFRP concrete decreased by 4.43%,8.88%,12.36%,20.43%and 25.26%.Cyclic loading and unloading caused fatigue damage to specimens,thus reducing the energy storage effect of concrete materials.Cause irreversible damage to it.(4)The strain at the corresponding mutation point of plain concrete,carbon fiber concrete,carbon fiber cloth concrete,carbon fiber and fiber cloth concrete is 0.64%,1.05%,1.00%and 1.68%,respectively.The use of fiber and fiber cloth increases the strain at the mutation point of concrete specimens,and the use of fiber can enhance the ductility of concrete materials.Cyclic loading and unloading reduces the ductility of the specimen.
作者
石烁
刘纪桦
张震
SHI Shuo;LIU Jiye;ZHANG Zhen(Puyang Polytechnic,Puyang 457000,China;School of Civil Engineering,Zhengzhou University,Zhengzhou 450001,China;Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China)
出处
《混凝土》
北大核心
2025年第7期68-73,共6页
Concrete
基金
国家自然科学基金(52108183)。
关键词
疲劳荷载
碳纤维
碳纤维布
纵波波速
峰值应力
突变点应变
fatigue load
carbon fiber
carbon fiber cloth
longitudinal wave velocity
peak stress
abrupt point strain
