Investigations on the Fracture Properties of the Full-Graded Dam Concrete under Increasing Amplitude Cyclic Loading

Cracking of full-graded dam concrete (FGDC) is a significant challenge for high arch dams, and such cracking is a substantial risk of damage and failure in an earthquake. To investigate the fracture properties of FGDC, increasing amplitude cyclic fracture tests were conducted. The results indicate that the failure load of FGDC increases with increasing frequency. The evolution of crack mouth opening displacement at maximum load can be divided into three stages. Acoustic emission (AE) and digital image correlation (DIC) were used to characterize the fracture process. A three-stage characteristic is also noted in the distribution of AE hits, and the transition times are identified by the Akaike information criteria picker. With increasing frequency, the first transition time increases, whereas the second transition time decreases. Furthermore, AE events are classified into four levels according to their absolute energy and localized. DIC is employed to trace the cracking process and reveal its brittle failure characteristic. Finally, it is verified that the b-value can be used to characterize the failure process of FGDC under cyclic fracture tests at different frequencies.