PT Journal AU Matysik, M Plskova, I Korenska, M Kucharczykova, B TI NDT of Mechanical Damaged Concrete Specimens by Nonlinear Acoustic Spectroscopy Method SO Transactions on Transport Sciences PY 2009 BP 166 EP 171 VL 2 IS 4 DI 10.5507/tots.2009.024 DE non-linear acoustic spectroscopy; light concrete; freeze-thaw cycles AB Current research and development of non-linear ultrasonic spectroscopy methods shows these methods to be very promising for material testing and defectoscopy in the near future. Our experiments focused on the testing of lightweight concrete specimens using the single-frequency excitation method. We studied the concrete specimens' structure after having been stressed by a mechanical force. Measurements were realized before and after mechanical loading. ER