In recent years, enormous efforts have been devoted to accurately quantifying the residual load-bearing capacity of concrete at the material level when exposed to elevated temperatures. However, relatively less attention has been given to investigating the effects of dynamic events such as terrorist attacks, earthquakes, and hurricanes, which can cause complete collapse of concrete structures and have significant public and economic consequences. Hence, in the present study, a modified Kolsky compression bar system integrated with a momentum trapping technique was implemented to develop precisely controlled pre-/post peak high strain-rate loading to introduce distinctive states of damage inside the high strength concrete HSC-BBR9 specimens and to measure the corresponding plastic strain. Thereafter, the partially damaged specimens were tested to quantify the residual mechanical properties (e.g., residual stiffness and residual strength) at different plastic strain levels. Furthermore, a high-resolution laboratory micro-CT scanner was used to visualize the 3D crack network morphology in the partially damaged specimens. The findings demonstrated a remarkable decrease in the residual capacity with increasing levels of damage-induced plastic deformation. Additionally, the results showed a fundamental difference in the influence of internal damage on residual stiffness and strength to be acknowledged in the formulations of future constitutive damage models for concrete materials.

中文翻译：

---

高强混凝土BBR9在动单轴压缩荷载作用下的残余力学性能

近年来，人们付出了巨大的努力来准确量化混凝土暴露在高温下时的材料水平残余承载能力。然而，对恐怖袭击、地震和飓风等动态事件影响的研究相对较少，这些事件可能导致混凝土结构完全倒塌，并产生重大的公共和经济后果。因此，在本研究中，采用改进的 Kolsky 压缩杆系统与动量捕获技术集成，以开发精确控制的峰值前/峰值后高应变率载荷，以在高强度混凝土 HSC-BBR9 样本内引入独特的损伤状态并测量相应的塑性应变。此后，对部分损坏的样本进行测试，以量化不同塑性应变水平下的残余机械性能（例如，残余刚度和残余强度）。此外，还使用高分辨率实验室微型 CT 扫描仪对部分损坏样本中的 3D 裂纹网络形态进行可视化。研究结果表明，随着损伤引起的塑性变形水平的增加，残余容量显着下降。此外，结果表明，内部损伤对残余刚度和强度的影响存在根本差异，在未来混凝土材料本构损伤模型的制定中需要承认。