Comparative study on the impact-induced microstructural damage in concrete using X-ray computed micro-tomography

To better understand the failure behavior of cementitious materials during dynamic loading, microstructural damage initiation and development in an ultra-high-performance concrete (UHPC) a special type conventional (CC) with average aggregate size only 2–3 mm are comparatively studied using X-ray computed micro-tomography (micro-CT) technique. Quantitative measurements reconstructed 3D crack morphology performed on specimens recovered from controlled intermittent loading experiments, different extents introduced through modified Kolsky bar apparatus. By correlating history specimen within bulk, quantitative relationship between several parameters (e.g., volume, surface area, void-crack interaction) increasing plastic strain obtained. The results demonstrate formation cracks prior to peak stress reveal fundamental difference two concretes being investigated. Further evaluation measured calculated constitutive variables indicates that compared UHPC, CC is capable sustaining considerable post-peak softening its residual mechanical properties (strength stiffness) more susceptible bulk material. Comparative analyses distribution void subsets also inherent connection pre-existing large-size voids material loading-induced network. These experimental provide comprehensive view evolution mechanisms for these under conditions may shed light future multi-scale models.