The Possibility of Using Nonlinear Acoustic Spectroscopy with a Single Excitation Signal for Testing of Concrete Elements Damaged by High Temperature

This paper focuses on the use of nonlinear acoustic spectroscopy with one excitation signal for NDT of concrete parts exposed to high temperature. The rate of the temperature rise, the highest achieved temperature, time of exposure to elevated temperature and the cooling rate has an influence on the overall damage of concrete structures affected by fire. The test specimens described in this paper have been heated for various periods of time and at a different temperature. Nonlinear acoustic spectroscopy method was performed before and after heat load.