A study of loading rate effect fracture behavior of concrete based on digital image correlation and finite-element method

To study the rate effect on the fracture properties of concrete, 700 mm × 150 mm × 100 mm specimens with a 60-mm notch were used for three-point bending test at the loading rate of 0.0005, 0.005, 0.05, and 0.5 mm/s, respectively. In the test, digital image correlation was used for monitoring the fracture process. The result shows that the fracture stress, unstable fracture toughness, and fracture energy have rate sensitivity. The numerical simulation was performed by extended finite-element model. The model calibration had a very good agreement with the experimental result under different loading rate. Meanwhile, fracture process zone length calculated by digital image correlation is similar to the result obtained by the extended finite-element model under different loading rate.