Measuring the Acoustic Characteristics of Compact Concrete Building Structures Using the Impact Echo Method

The impact-echo method, which is a method of free vibrations, is used for testing building structures made of concrete that have the measured thickness H at least six times smaller than the other dimensions and is not used to test compact products in which the thickness H is comparable to the other dimensions. The problem with testing compact objects is that it is impossible to unambiguously determine the required resonant frequency f_0∼1/H determined by the product thickness H on the spectrum of the compact product against the background of closely spaced numerous resonances determined by other test object dimensions. Another reason is that due to a strong influence of the geometric dispersion of the sound speed in compact products, it is necessary to calculate a correction factor β for each new compact test object. The article proposes a solution to the problem of testing compact concrete building structures using a multiplicative impact echo method that allows one to determine the desired resonant frequency, as well as using various versions of the correlation impact echo method that allow one to measure the speed of sound in compact products for the subsequent determination of concrete strength both in the process of cement solidification and during the operation of building structures in order to predict the trouble-free service life of buildings and structures.