A concrete rebound hammer tester is a tool used to measure the hardness and strength of concrete. It works by measuring the rebound or bounce height of a spring-loaded mass when it strikes the surface of the concrete. The rebound height is proportional to the hardness of the concrete and can be used to estimate its compressive strength. The concrete rebound hammer tester is a non-destructive testing method that is quick, simple, and inexpensive, making it a popular choice for evaluating the quality of concrete in construction projects. The test results can be used to identify weak or damaged areas of concrete and to ensure that the concrete meets minimum strength requirements for structural safety.

Rebound Hammer test is a Non-destructive testing method of concrete which provide a convenient and rapid indication of the compressive strength of the concrete. The rebound hammer is also called as Schmidt hammer that consist of a spring controlled mass that slides on a plunger within a tubular housing.

To use a concrete rebound hammer tester:
Calibrate the rebound hammer tester according to the manufacturer's instructions.
Clean the surface of the concrete where you want to take the measurement.
Position the tester so that the impact point is centered over the concrete surface and perpendicular to it.Strike the concrete surface with the rebound hammer, holding the tester firmly.
Read the rebound value from the tester's display.
Repeat the measurement several times at different locations on the concrete surface to obtain an average value.
The rebound value can be used to estimate the concrete's compressive strength. The relationship between rebound value and compressive strength will depend on the specific rebound hammer tester you are using and the type of concrete.
Refer to the manufacturer's instructions or a reference manual for specific instructions on how to interpret the rebound value.

Note: It is important to use the correct procedures and follow the manufacturer's instructions when using a concrete rebound hammer tester to ensure accurate and reliable results.
 
Typically, the manufacturer of the rebound hammer will provide a conversion chart or equation that relates the rebound value to the compressive strength of the concrete. Some rebound hammers also have built-in software that performs the calculation for you.
 
It is important to note that the compressive strength estimated from a rebound value is an indirect measure, and the actual compressive strength of the concrete can only be determined by conducting a laboratory test.
 
To obtain accurate results, it is also important to follow proper testing procedures and to consider factors such as surface cleanliness, temperature, and moisture content of the concrete.
 
It is advisable to consult the manufacturer's instructions or a reference manual for specific instructions on how to interpret the rebound value for the specific rebound hammer you are using.