Correct option is C
The Concrete Rebound Hammer Test, also
known as the Schmidt Hammer Test, is a widely used non-destructive testing method. This test provides a quick and convenient assessment of the compressive
strength of concrete on-site. The principle behind the test involves striking the concrete surface with a rebound hammer, and the rebound distance of the hammer correlates with the concrete's hardness and, consequently, its compressive strength. The rebound hammer test is valuable for quality control, assessing in-place concrete strength, and identifying potential areas of concern in structures without the need for
destructive sampling.
Components: Release Button: This does not move with the mass. It is only used to trigger the release of the spring. Scale: This is fixed and does not move. It is used to measure the rebound distance.
Rider: This is the component that actually moves with the mass. After the mass impacts the surface
and rebounds, the rider moves along the scale to show the rebound distance. The final position of the rider gives the rebound number, which is used to infer material properties.
Plunger: This also does not move with the mass after it rebounds. The plunger is pushed inwards by the initial force but remains in place during the rebound.
