Quantitative vibration mode analysis of mortar and concrete blocks containing flaws

Abstract Impact resonance testing was carried out on mortar and concrete specimens containing artificial flaws. The observed peak frequencies in the impact resonance tests were identified with the possible normal modes of the blocks, and the depth and size of the flaws were determined by the resonant frequencies of the specimens. The frequency spectra of the mortar and concrete blocks were similar; however, the peak frequencies and peak widths of the concrete specimen were slightly higher and broader respectively than those of the mortar block. The flaw size, shape and location determined by the impact resonance tests were in good agreement with the real ones, and the results suggest that concrete can be treated as a homogeneous and isotropic material in impact resonance testing.