Schmidt Rebound Hammer Test

• Schmidt hammer test is conducted to find out the compressive strength of concrete by using a Schmidt hammer. The rebound of any elastic mass depends upon the hardness of the surface of any material.

When the plunger of the Schmidt hammer test is pressed against any surface, the piston rebounds and the extent of such a rebound depends on the surface hardness of the concrete.

The spring-loaded piston of the hammer must travel with a consistent and reproducible velocity. The rebound distance of the steel hammer from the steel plunger is measured on a linear scale attached to the frame of the instrument.

The tests can be performed in any intermediate angled positions in relation to the surface. The devices are furnished with correlation curves by the manufacturer. Further these curves are refined with the help of testing carried out by various other methods to prepare the correlations like ultrasonic pulse velocity, concrete coring compression testing and capo test.