How do you calibrate a rebound hammer?

How do you calibrate a rebound hammer?

The cap has an adjustment screw and nut, which are used to calibrate the Rebound Hammer. 2. Using a 10 mm wrench, loosen the adjustment nut away from the cap. If the Rebound Hammer is reading low, tighten the adjustment screw (clockwise) into the cap.

How do you calculate rebound hammer results?

Higher strength is calculated by the rebound hammer on concrete that is subjected to carbonation. It is estimated to be 50% higher. So the hammer tests have to be performed by removing the carbonated layer and testing by rebound hammer over the non-carbonated layer of concrete.

How accurate is rebound hammer test?

As such, the estimation of strength of concrete by rebound hammer method cannot be held to be very accurate and probable accuracy of prediction of concrete strength in a structure is ±25 percent.

How is a Schmidt hammer calibrated?

Prior to testing, the Schmidt hammer should be calibrated using a calibration test anvil supplied by the manufacturer. Twelve readings should be taken, dropping the highest and lowest, and then taking the average of the ten remaining.

What are the limitations of rebound hammer test?

Limitations of Rebound Hammer Test:

• Rebound hammer has to be used against smooth and formed surface.
• Rebound hammer test should not be carried out on low strength concrete at early ages.
• Rebound hammer test evaluates surface hardness and in no way gives the exact compressive strength.

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.

What is the rebound hammer test?

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 is the is code for rebound hammer test?

Objective of Rebound Hammer Test As per the Indian code IS: 13311(2)-1992, the rebound hammer test have the following objectives: To determine the compressive strength of the concrete by relating the rebound index and the compressive strength. To assess the uniformity of the concrete.

Which of the following is the disadvantage of rebound hammer test?

Concrete with high honeycombs and no-fines concrete is not suitable to be tested by rebound hammer. The strength is overestimated by the test when testing floated or trowel surfaces when compared with moulder surfaces. As time passes, the relation between the strength and hardness of concrete will change.

What is rebound hammer test?

Is code for rebound hammer?

What is use of rebound hammer test?