Investigation of dynamic compression performance of high-strength concrete under near-field impact based on high-speed DIC

In order to gain insight into the damage characteristics and high strain rate mechanical response of high-strength concrete materials in assembled precast bridge structures under near-field impact loading, uniaxial impact compression tests were conducted on C60 and C80 high-strength concrete using a 100 mm large-diameter split Hopkinson pressure bar ( SHPB ). Dynamic parameters such as stress-strain curves, dynamic modulus of elasticity and dynamic increase factor of the concrete were obtained. The high-speed digital image correlation ( DIC ) technology was used to study the strain field on the concrete surface and analyze the crack propagation process during the failure process. Test results show that: the dynamic compressive strength of high-strength concrete specimens under high strain rate shows obvious strain rate effect, but its modulus of elasticity remains constant. And the logarithmic function model can better characterize the dynamic strength evolution pattern of high-strength concrete under high strain rate. Macroscopically, the observed damage patterns can be classified into four modes: intact specimen, axial splitting, concrete bursting, and crushing. At high strain rates, the instability of crack and its expansion rate increases with strain rate. © 2023 Chinese Vibration Engineering Society. All rights reserved.