The ultrasonic method is a non-destructive investigation method applicable to concrete structures for determining the speed of propagation of longitudinal waves (P-waves) within the hardened concrete.
The instrumentation used to perform the test is constituted by a central control unit of the signal and two transducers - the probe emitting and the receiving - characterized, for conventional applications, from a signal frequency of 54 kHz. The tool allow us to measure the time of flight of the ultrasonic signal within the concrete and, given the distance between the transducers, it is possible to calculate the speed of propagation of longitudinal waves.
The study of the mode of propagation of the pulse allow us to deduce information concerning the mechanical properties of the concrete, such as the normal dynamic elastic modulus, and the homogeneity of the material by determining the presence of any cavity (linked to the jet) , detachment of the concrete cover or cracks.
Besides the study of the characteristics of the concrete casting, an important feature of the survey it is offered by ultrasonic means of measuring the depth of lesions in reinforced concrete elements.