Li Guodong, Gu Jiarui, Ren Zhengyi, Zhao Fengnian, Zhang Yongquan
Transportation Institute, Inner Mongolia University, Inner Mongolia, Hohhot 010070, China.
Inner Mongolia Engineering Research Center of Testing and Strengthening for Bridges, Inner Mongolia, Hohhot 010070, China.
Materials (Basel). 2021 Oct 17;14(20):6161. doi: 10.3390/ma14206161.
This study presented evaluation of a concrete damage process by the acoustic emission (AE) technique under uniaxial multi-step compressive loading procedure combined with digital image correlation (DIC). The results showed that AE elastic wave velocity had good stress dependence in the damage process of concrete specimens with different sizes (cube, prism) and coarse aggregate characteristics (volume fraction, maximum size), and the effects of specimen sizes and coarse aggregate characteristics on the stress dependence can be nearly neglected. The standard deviation of 32 AE elastic wave velocities was used as the criterion to evaluate the relative stress ratio of concrete under different damage states, and the damage process of concrete was divided into three damage stages according to this criterion. When the standard deviation is below 70, in the range of 70 to 1700, and greater than 1700, the concrete damage process is defined as steady damage process, accelerated damage process and buckling damage process, respectively. The accuracy of the presented evaluation methodology was demonstrated by comparative results with digital image correlation. The results indicate that the standard deviation of AE elastic wave velocities can potentially serve as a reliable, convenient, and non-destructive evaluation criterion of concrete damage state under uniaxial compressive loading.
本研究通过声发射（AE）技术，结合数字图像相关（DIC）方法，对混凝土在单轴多步压缩加载过程中的损伤过程进行了评估。结果表明，在不同尺寸（立方体、棱柱体）和粗骨料特性（体积分数、最大粒径）的混凝土试件损伤过程中，AE弹性波速度具有良好的应力相关性，试件尺寸和粗骨料特性对应力相关性的影响几乎可以忽略不计。以32个AE弹性波速度的标准差作为评估不同损伤状态下混凝土相对应力比的标准，并据此将混凝土损伤过程分为三个损伤阶段。当标准差低于70、在70至1700范围内以及大于1700时，混凝土损伤过程分别定义为稳定损伤过程、加速损伤过程和屈曲损伤过程。通过与数字图像相关的对比结果验证了所提出评估方法的准确性。结果表明，AE弹性波速度的标准差有可能作为单轴压缩加载下混凝土损伤状态可靠、便捷且无损的评估标准。
