Non-Destructive Testing of High Temperature Degraded Concrete Composite of Portland Cement CEM I 42.5 R and Gravel Aggregate 11/22 by Transverse Waves

This paper study applicability of non-destructive method of impact echo for diagnosis of high temperature degraded plain concrete. Impact echo method is often used for detection of defects, cracks, and non-homogeneity in constructions. It's based on impact-generated mechanical wave that propagate through the mass of testing specimen and is reflected and partially absorbed by voids and surface. In this paper, we present results of an experiment where test specimens of dimension 0.1 x 0.1 x 0.4 m were created with usage of coarse aggregate 11/22 mm. Specimens has been divided to 7 sets. First set of test specimens were kept at laboratory conditions as a reference. Next six sets were heated up to 1200 ° C. After this heating, the specimens were cooled spontaneously and then tested by impact echo method. We used a steel hammer as an exciter of mechanical wave, which has been transferred to signal by the piezoelectric sensor. Then we analyzed this signal and we focused on transverse waves. Results from non-destructive tests were compared with results from destructive tests.