Abstract: To verify the effectiveness and applicability of Impact-Echo method in detecting the thickness and internal defects of concrete structures, in this study we design defect-free concrete specimens and concrete specimens containing different types and properties of defects in line with common defects of concrete structure in practical engineering, and apply Impact-Echo method to testing these model specimens. The basic characteristics and influence factors of low frequency stress wave excited by the impact echo method are studied, and the detection techniques and application range of impact echo method are analyzed systematically. Research results show that the impact echo method is currently the most effective non-destructive testing method for concrete structures with only a single detection surface. Within its scope of application, satisfactory detection results can be achieved, yet still with some limitations in the test capability.

Key words: concrete structure, internal defects of concrete, Impact-Echo method, non-destructive testing, model test