In this paper, we describe a method of evaluating the strength of concrete by the quality factor of the resonant peak of multireflected elastic waves propagating inside the concrete. An electromagnetic-induction-type sound source and a piezoelectric transducer are employed as an elastic wave transmitter and a receiver, respectively. Linear predictive coefficient processing and resonant analysis methods are employed for spectrum derivation and quality factor calculation, respectively. Three types of concrete specimen with the same dimensions but different strengths are measured, with variations in the geometrical arrangement of the sound source and receiver. Although it is difficult to distinguish the differences in strength from the time domain signals, the quality factors of the resonant peaks of multireflected elastic waves corresponding to different types of concrete show stable results, and this tendency agrees well with that of the concrete strengths.

No abstract

No abstract

No abstract

No abstract