What is the purpose of rebound hammer test?

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

Is rebound hammer test reliable?

Nevertheless, the rebound hammer can be a reliable device for assessing the general condition of a structure and the homogeneity of concrete, provided that it is calibrated and a rebound correlation curve is developed and used for the specific type of concrete to be tested.

Is rebound hammer test a NDT?

The rebound hammer is a nondestructive testing apparatus, whereby the rebound of the spring driven mass is measured after its impact with concrete surface. The output of the rebound hammer is referred to as rebound number and are correlated with surface hardness of concrete.

What are the limitations of rebound hammer test?

Rebound hammer test should not be carried out on low strength concrete at early ages. When the concrete strength is less than 7 N/mm2, the concrete surface could be damaged by the hammer.

Which part of rebound hammer is useful?

Procedure To Determine Strength Of Hardened Concrete By Rebound Hammer

Average Rebound Number	Quality of Concrete
>40	Very good hard layer
30 to 40	Good layer
20 to 30	Fair
< 20	Poor concrete

How rebound hammer test is done?

Procedure: The instrument firmly held perpendicular to the test surface and gradually pushed toward the test surface until the hammer impact. After impact, the pressure is maintained on the instrument. The rebound number is read on the scale to the nearest whole number and recorded.

Is the rebound hammer test a legitimate way to determine the strength of in place concrete?

Hence we can conclude that rebound hammer test results do not give the accurate strength of concrete. It is only useful for repairs as the strength of different elements at different locations can be compared relatively.

Which quality of concrete is tested by rebound hammer Mcq?

Rebound hammer is an instrument or a device, which is used to assess the relative compressive strength of concrete based on the hardness at or near its exposed surface.

What is the normally used rebound hammer for NDT?

Interpretation of results:

Average Rebound Number	Quality of Concrete
› 40	Very Good
30-40	Good
20-30	Fair
<20	Poor and/or delaminated

What is meant by calibration of rebound hammer?

Calibration and Reliability of the Rebound (Schmidt) Hammer Test. The typical procedure for calibrating a test is that of producing specific specimens with different strength but with the same concrete type (aggregate size and type), as in the previous section.

Which is good quality of concrete values of rebound hammer?

Which statement is true for rebound hammer test?

∴ Statement 4 is correct. Rebound Hammer Test: Rebound hammer test is a non-destructive testing method of concrete that provide a convenient and rapid indication of the compressive strength of the concrete. The rebound hammer is also called as Schmidt hammer.