The rebound number determined by this method can be used to assess the uniformity of concrete in situ, to delineate zones or areas of poor quality or deteriorated concrete in structures.
This NDT test method is not intended as an alternative for the compressive strength determination of concrete, but with suitable correlations already saved in the instrument, it provides an estimate of the in situ compressive strength.
The hammer may be used for comparative testing, referenced against a concrete with known strength or against a concrete verified as conforming to a particular strength class.
The rebound hammers measure the rebound of an anvil impacting a plunger in contact with the concrete surface.
With this advanced instrument the rebound value is calculated with an innovative technology taking into account the anvil speed before and after the impact.
This new working principle is equivalent to the traditional measurement of maximum spring length after the impact, but it provides the following benefits:

• higher accuracy and stability of the readings not affected by wear and tear
• setting of the impact angle no longer required
• a check of the device reliability can be performed during each impact, even without the calibration anvil.