Hammer Test

A Schmidt hammer, also known as a Swiss hammer or a rebound hammer, is a device to measure the elastic properties or strength of concrete or rock, mainly surface hardness and penetration resistance.

The operation is being executed as, When the plunger of rebound hammer is pressed against the surface of concrete, a spring controlled mass with a constant energy is made to hit concrete surface to rebound back. The extent of rebound, which is a measure of surface hardness, is measured on a graduated scale. This measured value is designated as Rebound Number (rebound index). A concrete with low strength and low stiffness will absorb more energy to yield in a lower rebound value.

The rebound hammer test method is used for the following purposes:
(a)  To find out the likely  compressive  strength  of  concrete  with  the  help  of suitable co-relations between rebound index and compressive strength.

(b)  To assess the uniformity of concrete.

(c)  To assess the quality of concrete in relation to standard requirements.

(d)  To assess the quality of one element of concrete in relation to another.