Monte Carlo simulations of meso-scale dynamic compressive behavior of concrete based on X-ray computed tomography images

• XCT-image based concrete meso-models built for dynamic MCS for the first time.
• A new CDIF–strain rate relation proposed with statistical information up to 100/s.
• A new strength–strain rate–void content relation proposed for the first time.
• Damage develops into more complicated crack networks at higher strain rates.
• The dynamic behavior is more sensitive to void contents at higher strain rates.

The dynamic damage and fracture behavior of concrete under compression with strain rate up to 100 s−1 is investigated by Monte Carlo simulations (MCSs) of realistic meso-scale models based on high-resolution micro-scale X-ray computed tomography (XCT) images, using the concrete damaged plasticity (CDP) model. For a given strain rate, 93 2D XCT images of a 37.2 mm concrete cube are simulated to obtain statistical results of macroscopic stress–strain curves. The predicted compressive dynamic increase factor (CDIF)–strain rate curve is in good agreement with existing experimental data and empirical curves. The effects of aggregate/void area fraction on dynamic compressive strength are also analyzed, and an augmented compressive strength-strain rate relation considering the void area fraction is proposed. A full 3D model is also simulated under various strain rates. It is found that the realistic XCT-image based meso-models with the CDP model are very promising in effectively elucidating the complicated and fundamental dynamic failure mechanisms of concrete.