Material Damage Evolution for Plain and Steel-Fiber-Reinforced Concrete Under Unconfined Compression Loading by Dynamic Ultrasonic Tests

This paper summarizes the results of a research aimed at assessing the damage of plain and steel-fiber-reinforced concrete when using ultrasonic compression and shear wave velocities. The ultrasonic waves and the axial compression loading were oriented to the same direction in order to track the damage progress during several loading steps. The concrete damage was monitored based on the evolution of the dynamic mechanical properties. The experimental program included 18 cylindrical specimens from six different mixtures that were cast by using 0, 0.3 and 0.5% fiber volume contents. Quantitative models were established linking the axial loads, the wave velocities, the dynamic Young's and shear moduli, the Poisson's ratio and a damage index.