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Impact-echo (IE)

Impact-echo (IE) is an ultrasonic testing technique that entails introducing mechanical energy, in the form of a short pulse, into a structure and measuring its response. A transducer mounted on the impacted surface of the structure receives the reflected input waves or echoes as changes in the acoustic impedance in the materials are detected. Spectral analysis of the reflected compression wave is then performed to identify flaws and/or deterioration in the concrete or other material and to measure the thickness.

YAES engineers have extensive experience using the IE test method. In the 1990s they collaborated with the Federal Highway Administration (FHWA) Turner-Fairbank Highway Research Center in McLean, VA in the research and development of the technology. YAES has applied the IE test method to identify concrete related problems in bridges, tunnels, slabs, foundations, pavements, and masonry and stone facades.


The IE test method is commonly used in concrete, stone, shotcrete, and masonry structures to detect internal flaws such as honeycombing, voids, and delaminations. It is also used to detect freezing and thawing deterioration, grout conditions in post-tensioned tendon ducts, and grout conditions in CMU construction. It is also an effective tool to assess the overall quality of concrete.


  • One-sided test method
  • Estimates concrete thickness without coring
  • System portability
  • Reliable and repeatable results when performed by experienced operators