基于声发射技术的冻融劣化混凝土单双轴动态抗压试验
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摘要
为研究混凝土材料在冻融循环后单双轴动态抗压时的力学性能,利用10 MN大型多功能液压伺服静动力三轴仪进行单、双轴试验,采用新型动态无损检测声发射技术实时采集声发射数据,分别建立不同加载速率、不同冻融循环次数下的应力和声发射参数与时间的对应关系,分析混凝土在不同工况下内部损伤破坏的过程及规律。结果表明,动态加载速率下,在加载前期无声发射能量信号产生,达到峰值应力附近时能量急剧释放;双轴状态下声发射最大能量滞后效应增大,卸载阶段有声发射能量产生;随着冻融循环次数的增加,损伤演化路径随冻融程度的加深逐渐发生前移。所建立的损伤模型能很好地反映由声发射能量数确定的损伤值D与应力水平V(%)之间的关系。
In order to study the mechanical properties of concrete materials in the dynamic compressive stress of the single dual-axis after freeze-thaw cycle,a uniaxial and biaxial test were carried out using 10 MN large multi-function hydraulic servo hydrodynamic triaxial instrument.The corresponding relationship between stress and acoustic emission parameters of different loading rate,different freeze-thaw cycle times and time was established by using real time acquisition acoustic emission data with dynamic nondestructive test coustic emission technology.The process and law of internal damage and failure of concrete under different working conditions were analyzed.The result shows that under the dynamic loading rate,the silent emission energy signal is generated before the stress loading,and the energy is released rapidly when the peak stress is reached;Under the uniaxial condition,the maximum energy lag effect of AE is obvious,and there is almost no acoustic emission energy during the unloading stage.The established damage model can well reflect the relationship between the damage value D and the stress level V(%)determined by the AE energy number.
In order to study the mechanical properties of concrete materials in the dynamic compressive stress of the single dual-axis after freeze-thaw cycle,a uniaxial and biaxial test were carried out using 10 MN large multi-function hydraulic servo hydrodynamic triaxial instrument.The corresponding relationship between stress and acoustic emission parameters of different loading rate,different freeze-thaw cycle times and time was established by using real time acquisition acoustic emission data with dynamic nondestructive test coustic emission technology.The process and law of internal damage and failure of concrete under different working conditions were analyzed.The result shows that under the dynamic loading rate,the silent emission energy signal is generated before the stress loading,and the energy is released rapidly when the peak stress is reached;Under the uniaxial condition,the maximum energy lag effect of AE is obvious,and there is almost no acoustic emission energy during the unloading stage.The established damage model can well reflect the relationship between the damage value D and the stress level V(%)determined by the AE energy number.
引文
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[6] 钱涛,岑国平,张严,等.高寒环境下掺外加剂水泥混凝土抗冻融性能研究[J].混凝土,2011(12):83-87.
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[9] 张明,李仲奎,杨强,等.准脆性材料声发射的损伤模型及统计分析[J].岩石力学与工程学报,2006,25(12):2 493-2 501.
[10]千力.基于声发射技术的混凝土损伤评估[D].武汉:华中科技大学,2005.
[2] Song W L,Li X F,Ma K F.The Effect of Freeze-thaw Cycles on Mechanical Properties of Concrete[J].Advanced Materials Research,2010,163-167:3 429-3 432.
[3] Rao M,Li M,Yang H,et al.Effects of Carbona-tion and Freeze-thaw Cycles on Microstructure ofConcrete[J].Journal of Wuhan University of Tech-nology-Mater,Sci.Ed.,2016,31(5):1 018-1 025.
[4] Shang H S,Yi T H.Freeze-thaw Durability of Air-entrained Concrete[J].The Scientific World Jour-nal,2013(1):650791.
[5] 宋玉普,徐秀娟,刘浩.冻融循环后全级配混凝土及其湿筛混凝土的力学性能比较[J].水利学报,2012,39(1):69-75.
[6] 钱涛,岑国平,张严,等.高寒环境下掺外加剂水泥混凝土抗冻融性能研究[J].混凝土,2011(12):83-87.
[7] 田威,谢永利,党发宁.冻融环境下混凝土力学性能试验及损伤演化[J].四川大学学报:工程科学版,2015,47(4):38-44.
[8] 胡伟华,彭刚,黄仕超,等.基于声发射技术的混凝土动态损伤特性研究[J].长江科学院院报,2015(2):123-127.
[9] 张明,李仲奎,杨强,等.准脆性材料声发射的损伤模型及统计分析[J].岩石力学与工程学报,2006,25(12):2 493-2 501.
[10]千力.基于声发射技术的混凝土损伤评估[D].武汉:华中科技大学,2005.