湿筛混凝土循环拉伸和循环拉压力学特性

Cyclic Tensile and Cyclic Tension Compression Properties of Wet-Screened Concrete

关键词:  湿筛混凝土  循环拉伸加载  循环拉压加载  声发射

Key words:  wet-screened concrete  cyclic tensile loading  cyclic tension compression loading  acoustic emission

摘要:

为探究湿筛混凝土在循环轴拉作用下的损伤过程和裂缝演变规律，基于声发射（AE）技术，对加载速率为1、10 μm/（m·s）的混凝土试件分别进行循环拉伸和循环拉压试验. 结果表明：随着循环次数的增加，试件的卸载和重加载刚度降低，塑性应变增大；当位移达到0.1 mm时，试件的载荷-位移曲线已接近软化阶段，此后裂缝发展速率降低，损伤变量减小；试件在循环加载过程中，随着位移的增加，AE累计振铃计数和累计撞击次数基本呈阶梯式增长.

Abstract:

To investigate the damage process and crack evolution of wet screened concrete under the action of cyclic tensile and cyclic tension compression， the cyclic tensile tests and cyclic tension compression tests of concrete specimens with loading rates of 1，10 μm/（m·s） were carried out by acoustic emission （AE）. The results show that the speciments of the unloading and reloading stiffness decreases with the increase of the cycle times， and the plastic strain increases with the cyclic loading. When the displacement reaches 0.1 mm， the load displacement curve of the specimen is approaching the softening stage， and then the crack development speed decreases， and the damage index decreases. In the process of cyclic loading， with the increase of the displacement， the AE accumulative ring counts and the cumulative numbers of hit basically increase in a step pattern.