LABORATORIES
Impulse Response Testing
ASTM C1740
Standard Practice for Evaluating the Condition of Concrete Plates Using the Impulse-Response Method
Evaluating Subgrade Support Condition
Determining Change in Stiffness of a Structure
Locate Areas of Voiding Beneath Concrete Slabs
Impulse Response Testing - What is it?
Impulse response testing is a non-destructive testing (NDT) method used to evaluate changes in stiffness and support in concrete plate structures. The test involves applying a low-strain mechanical impact to the concrete surface with an instrumented hammer while a velocity sensor measures the resulting response of the structure. The relationship between the applied force and measured response is analyzed to identify changes in the dynamic behavior of the concrete.
Impulse response testing is particularly useful for identifying areas of loss of support beneath slabs and liners.
Testing is performed systematically across a grid, allowing results to be compared and mapped over large areas. Testing is typically performed in conjunction with impact-echo to pair changes in stiffness with thickness measurements.
After the completion of impulse response, impact echo and ground penetrating radar - areas suspected to have a loss of support beneath the slab are often selected for concrete coring or drilling to investigate the condition of the subgrade.
Impulse response testing is well suited for evaluating spillways where loss of support beneath chute slabs is a primary concern.
