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再生混凝土临界破坏特征及单轴压缩损伤本构方程
Critical failure characteristics and uniaxial compression damage constitutive equation of recycled concrete
【摘要】 制作了5组不同再生粗骨料取代率的再生混凝土棱柱体试件并进行单轴压缩试验,采集棱柱体试件单轴受压全过程声发射(AE)参数,绘制单轴压缩应力-应变曲线。通过分析声发射能量参数,绘制压缩破坏过程中时间-声发射累计能量曲线,采用幂函数Power公式对该曲线进行拟合,将试验曲线与拟合曲线进行对比,结合能量加速释放理论对再生混凝土损伤过程声发射能量释放规律进行分析;将声发射累计能量突增的时刻视为临界破坏点,用受压全过程采集的声发射振铃计数定义损伤变量,考虑再生掺量带来的初始损伤,用再生粗骨料取代率百分数定义再生参数,借助Weibull统计方法与损伤理论建立声发射损伤演化模型,建立考虑再生粗骨料初始缺陷影响的声发射损伤本构方程,并将新建方程拟合应力-应变曲线与试验曲线进行对比。结果表明:拟合曲线与试验曲线吻合良好,新方程能够较好地描述再生混凝土的损伤演化过程。
【Abstract】 Five groups of recycled concrete prism specimens with different recycled coarse aggregate replacement rates were made and uniaxial compression tests were carried out. The acoustic emission(AE) parameters of the whole process of uniaxial compression of the prism specimens were collected, and the uniaxial compression stress-strain curves were drawn. By analyzing the acoustic emission energy parameters, the time-acoustic emission cumulative energy curve in the process of compression failure was drawn, and the curve was fitted by the power function Power formula. The test curve was compared with the fitting curve, and the energy release law of acoustic emission energy in the damage process of recycled concrete was analyzed by combining the energy accelerated release theory. The time when the cumulative energy of acoustic emission increased suddenly was regarded as the critical failure point, and the damage variable was defined by the acoustic emission ringing count collected in the whole process of compression, considering the initial damage caused by the amount of recycled coarse aggregate, the regeneration parameters were defined by the percentage of recycled coarse aggregate replacement rate. The acoustic emission damage evolution model was established by means of Weibull statistical method and damage theory. The acoustic emission damage constitutive equation considering the influence of initial defects of recycled coarse aggregate was established, and the stress-strain curve fitted by the new equation was compared with the test curve. The results show that the fitting curve is in good agreement with the experimental curve, and the new equation can better describe the damage evolution process of recycled concrete.
【Key words】 recycled concrete; acoustic emission; energy accelerated release; damage constitutive equation;
- 【文献出处】 建筑科学与工程学报 ,Journal of Architecture and Civil Engineering , 编辑部邮箱 ,2023年06期
- 【分类号】TU528
- 【下载频次】81