Identification of brittle damage in a UHPC beam using ultrasonic transmission tomography

This paper presents the results of ultrasonic testing conducted on a steel fiber-reinforced UHPC (Ultra-High Performance Concrete) beam with dimensions of 0.2 m × 0.24 m × 6.0 m. The beam was subjected to 13 loading stages, with an asymmetrical load application. For the first 11 loading stages, longitudinal ultrasonic wave propagation at a frequency of 150 kHz was measured prior to each loading step using an ultrasonic concrete tester. The recorded wave travel times were then processed in MATLAB using a least squares method with Tikhonov regularisation to reconstruct the damaged zones within the beam. The results enabled the identification of localised cracks and the progressive development of damage in the UHPC beam.