Impact-Echo (IE)

JS Building Diagnostics specializes in the use of the Impact-Echo (IE) nondestructive evaluation technique for existing condition assessment, material property evaluation, and quality assurance testing. Based on the principles of reflective ultrasonics, IE testing requires access to only one side of a structural element. The method is typically used to detect the size and location of internal concrete flaws like planar cracking, delamination, honeycombing, and debonding of layered and repair systems. Equipment specially developed for use on structural concrete and software that offers real-time assessment has made IE an invaluable tool in forensic investigations.

Methodology

IE testing is based on the spectral analysis of reflected waves. The method involves introducing mechanical energy in the form of a short pulse to the testing surface. Stress waves reflected from changes in acoustic impedance in the material are measured using a signal displacement transducer positioned near the impact point. With knowledge of the propagation velocity through the material, the amplitude spectrum of the received waveform can be analyzed to determine the depth to internal flaws or the back surface of the element. Data interpretation and analysis is required by experienced operators.

Common Applications

Existing Structural Concrete

  • Detection of internal flaws in building elements, tunnels, dams, retaining walls, foundations, and other concrete structures

  • Approximate thickness measurement of elevated slabs, slabs-on-grade, walls, and other plate-like members

  • Detection and location of embedded insulation and block-outs

  • Quality assurance testing of shotcrete applications

Existing Infrastructure

  • Detection of internal flaws in concrete bridge elements, including barrier walls, bridge framing elements, and piers

  • Delamination detection of bridge decks

  • Verification of grout integrity in embedded post-tensioning ducts

  • Approximate thickness measurement of pavements

Repair Evaluation

  • Assessment of bond quality in cementitious repairs and bonded overlays

  • Assessment of bond quality of FRP strengthening systems

  • Quality assurance testing of repairs