Evaluation of the dynamic properties of quasi-brittle materials is of the utmost
importance for assessing the vulnerability of structural components under dynamic loadings
such as collision or explosion. To investigate the dynamic strength of (quasi)-brittle
material, three-point bending tests are performed on a modified Split Hopkinson Pressure
Bar. Such an apparatus is often used with pre-cracked specimen to determine the dynamic
stress intensity factor of metallic materials. With quasi-brittle materials special care
has to be paid to the processing of the test since fracture can occur at very low strains.
The specimen remains in an out-of equilibrium state and fracture occurs before the support
reactions appear as if it was a support-free impact test. A special non-equilibrium
analytical approach has been developed to process the tests. Finite-element simulations
are used to assess relevance of the proposed analysis for normalized short beams.
Experimental results on brick and concrete samples showing a significant dynamic strength
increase are presented.