“zero-volume” defects

Adhesion in this system is one of the most important factors that affect the reliability and durability of repair. According to the many standards and guidelines, a pull-off test is recommended for assessment of  a bond quality in repair systems. However, a growing interest in development of non-destructive techniques (NDT) for evaluation of concrete structures is recently noted. A majority of NDT methods mentioned in EN 1504-10 for repair efficiency assessment are based on propagation of stress waves. The impact echo method is considered as a one of the promising.