Thiele Marc, Pirskawetz Stephan
Bundesanstalt für Materialforschung und-prüfung (BAM), 12205 Berlin, Germany.
Materials (Basel). 2022 Jan 4;15(1):341. doi: 10.3390/ma15010341.
The fatigue process of concrete under compressive cyclic loading is still not completely explored. The corresponding damage processes within the material structure are especially not entirely investigated. The application of acoustic measurement methods enables a better insight into the processes of the fatigue in concrete. Normal strength concrete was investigated under compressive cyclic loading with regard to the fatigue process by using acoustic methods in combination with other nondestructive measurement methods. Acoustic emission and ultrasonic signal measurements were applied together with measurements of strains, elastic modulus, and static strength. It was possible to determine the anisotropic character of the fatigue damage caused by uniaxial loading based on the ultrasonic measurements. Furthermore, it was observed that the fatigue damage seems to consist not exclusively of load parallel oriented crack structures. Rather, crack structures perpendicular to the load as well as local compacting are likely components of the fatigue damage. Additionally, the ultrasonic velocity appears to be a good indicator for fatigue damage beside the elastic modulus. It can be concluded that acoustic methods allow an observation of the fatigue process in concrete and a better understanding, especially in combination with further measurement methods.
混凝土在压缩循环加载下的疲劳过程尚未得到充分研究。材料结构内相应的损伤过程尤其没有得到全面调查。声学测量方法的应用有助于更深入地了解混凝土的疲劳过程。通过将声学方法与其他无损测量方法相结合，研究了普通强度混凝土在压缩循环加载下的疲劳过程。声发射和超声信号测量与应变、弹性模量和静态强度测量一起进行。基于超声测量，可以确定单轴加载引起的疲劳损伤的各向异性特征。此外，观察到疲劳损伤似乎不仅由与载荷平行的裂纹结构组成。相反，垂直于载荷的裂纹结构以及局部压实可能是疲劳损伤的组成部分。此外，除弹性模量外，超声速度似乎也是疲劳损伤的一个良好指标。可以得出结论，声学方法能够观察混凝土的疲劳过程并有助于更好地理解，特别是与其他测量方法结合使用时。
