碳纳米管混凝土三点弯曲梁的声发射及损伤演化特征  

Acoustic Emission and Damage Evolution Characteristics of Carbon Nanotube Concrete Three-Point Bending Beam

作　　者：李慧宽 黄山秀 陈小羊 郭佳奇[3] LI Huikuan;HUANG Shanxiu;CHEN Xiaoyang;GUO Jiaqi(College of Chemistry and Chemical Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China;Transportation Company of China Construction Seventh Engineering Division Co.,Ltd.,Zhengzhou 450004,Henan,China;College of Civil Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China)

机构地区：[1]河南理工大学化学化工学院,河南焦作454003 [2]中建七局交通建设有限公司,河南郑州454004 [3]河南理工大学土木工程学院,河南焦作454003

出　　处：《高压物理学报》2025年第1期86-97,共12页Chinese Journal of High Pressure Physics

基　　金：国家重点研发计划(2023YFC3805903);河南理工大学博士基金(B2024-34);中建七局交通建设有限公司委托项目(H22-661)。

摘　　要：为研究碳纳米管掺量对混凝土梁损伤演化过程及裂纹扩展规律的影响,制备了质量分数分别为0、0.1%、0.3%、0.5%的碳纳米管混凝土三点弯曲梁试件。采用搭载声发射测试系统的YNS300电液伺服万能试验机开展三点弯曲试验,得到了声发射能量、振铃计数和幅值等声学信息,并基于声发射参数对裂纹类型、损伤演化过程进行分析。结果表明:碳纳米管混凝土三点弯曲梁破坏时产生的声发射能量明显高于素混凝土梁,但随着碳纳米管掺量的增加,其破坏时产生的声发射能量逐渐减小;碳纳米管的掺入可以提高混凝土三点弯曲梁的承载能力,但超过某一界限后,其承载能力随着碳纳米管掺量的增加而降低;碳纳米管的掺入使得混凝土三点弯曲梁第一次声发射幅值突变的时间提前,试样破坏前,振铃计数及累计振铃计数增长缓慢,近似直线,试样断裂瞬间,两者均急剧上升;声发射信号源隶属于拉伸裂纹,碳纳米管混凝土三点弯曲梁断裂属于Ⅰ型断裂,拉伸裂纹和剪切裂纹占比与碳纳米管掺量之间没有明显关系,但声发射平均频率、上升角度信号源数量与碳纳米管掺量之间具有显著的相关性。不同碳纳米管掺量下,混凝土三点弯曲梁试样的损伤演化规律基本保持一致,试验前期损伤曲线基本为水平直线,破坏阶段损伤变量首先处于快速增长阶段,而后呈陡增式增长。To study the impact of the content of carbon nanotubes(CNTs)on the damage evolution and crack propagation in concrete beams,concrete three-point bending beam specimens containing 0,0.1%,0.3%,and 0.5%CNTs were prepared.The three-point bending tests were conducted by using the YNS300 electro-hydraulic servo universal testing machine equipped with an acoustic emission(AE)testing system.Acoustic information such as AE energy,ringing count,and amplitude were obtained.The crack type and damage evolution process were analyzed based on AE parameters.The results show that the AE energy of carbon nanotube concrete(CNTC)three-point bending beam is significantly higher than that of plain concrete beams.However,as the content of carbon nanotubes increases,the AE energy generated during failure gradually decreases.The addition of CNTs can improve the bearing capacity of concrete beam.However,after exceeding a certain threshold,the load-bearing capacity decreases as the CNTs increases.The incorporation of carbon nanotubes advances the time of the first amplitude mutation in the concrete threepoint bending beams.Prior to the failure of the specimens,the ringing count and cumulative ringing count increase slowly,approximating a straight line.However,at the instant of specimen fracture,both of them rise sharply.The AE signal sources belong to the tensile crack.The fracture of carbon nanotube-reinforced concrete three-point bending beams is classified as ModeⅠfracture.There is no significant relationship between the proportions of tensile-shear cracks and the CNTs content.However,the number of AE average frequency and angle of rise of signal sources is significantly correlated with the CNTs content.The damage evolution law of concrete beam samples with different CNTs is basically consistent.In the early stage of the test,the damage curve is basically horizontal,and the damage variable in the failure stage is in a rapid growth stage at first,and then abruptly increases.

关 键 词：碳纳米管 混凝土梁 损伤演化 裂纹扩展 声发射 

分 类 号：O347.4[理学—固体力学] TU45[理学—力学] O521.9[建筑科学—岩土工程]