Air-coupled ultrasonic diffuse-wave techniques to evaluate distributed cracking damage in concrete

Eunjong Ahn, Myoungsu Shin, John S. Popovics

Research output: Contribution to journalArticlepeer-review


In this study, we investigated the suitability of applying air-coupled ultrasonic diffuse-wave techniques to concrete structures for the evaluation of arbitrarily distributed micro-cracking damage. Air-coupled test results were compared with those obtained using a conventional full-contact measurement system. Three different micro-cracking damage levels were simulated by embedding varying amounts of low-stiffness polypropylene fibers in concrete samples. Two principal diffuse-wave parameters, diffusivity and dissipation, were determined using air-coupled and full-contact test configurations. Wave frequencies of 300–600 kHz were employed, which set up significant ultrasonic scattering owing to the heterogeneous characteristics of concrete components (e.g., aggregates, micro-cracks expressed by fibers, and pores). In addition, the sensitivities of diffusivity and dissipation to the number of measurement locations were examined. The results demonstrated that the air-coupled method can provide an equivalent reliability to the full-contact method, allowing a much faster and flexible data collection. The spatial averaging of 20 arbitrarily selected data (measured at different locations) yielded sufficiently accurate diffuse-wave parameters, showing less than a 5 % difference from the average of 32 spatially different data.

Original languageEnglish (US)
Article number106800
StatePublished - Sep 2022


  • Air-coupled ultrasound
  • Diffuse wave
  • Diffusivity
  • Dissipation
  • Distributed cracking damage
  • Non-destructive evaluation

ASJC Scopus subject areas

  • Acoustics and Ultrasonics


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