How do you find the compressive strength of concrete from a rebound number?

Compressive strength (N/mm2) = Maximum crushing load / Cross – sectional area of specimen. Schmidt Rebound Hammer test is a non- destructive test.

How will you assess the quality of concrete from rebound numbers?

When the plunger of rebound hammer is pressed against the surface of concrete, a spring controlled mass with a constant energy is made to hit concrete surface to rebound back. The extent of rebound, which is a measure of surface hardness, is measured on a graduated scale.

How do we interpret the results of rebound hammer test?

6. Interpretation of Result. The rebound hammer method provides a convenient and rapid indication of the compressive strength of concrete by means of establishing a suitable correlation between the rebound index and the compressive strength of concrete. The procedure of obtaining such correlation is given in 4.2.

How do you find compressive strength?

Calculating Compressive Strength The formula is: CS = F ÷ A, where CS is the compressive strength, F is the force or load at point of failure and A is the initial cross-sectional surface area.

How do you calculate the compressive strength of concrete?

The compressive strength was calculated by using the equation [14] : F= P/A, where F is compressive strength of specimen in Mega Pascal, P is the maximum applied load by newton and A is the cross-sectional area estimated in mm 2 . …

What is compressive strength of concrete?

Compressive strength of concrete is the Strength of hardened concrete measured by the compression test. The compression strength of concrete is a measure of the concrete’s ability to resist loads which tend to compress it. It is measured by crushing cylindrical concrete specimens in compression testing machine.

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 value of compressive strength?

The average compressive strength values ranged between 10.2 and 22.2 MPa at a strain of 0.1.

What is compressive strength example?

Compression is a force that pushes the particles of a material closer together. For example, when a column supports a load, it is under compression and its height shortens, albeit often imperceivably. Materials which can resist high, applied compressive forces before failure are said to have high compressive strengths.

How do you solve for compressive strength?

How to measure compressive strength of concrete with rebound number?

The most suitable method of obtaining the correlation between compressive strength of concrete and rebound number is to test the concrete cubes using compression testing machine as well as using rebound hammer simultaneously.

How do you read the rebound on a concrete hammer?

Thus, the hardness of concrete and rebound hammer reading can be correlated with compressive strength of concrete. The rebound value is read off along a graduated scale and is designated as the rebound number or rebound index. The compressive strength can be read directly from the graph provided on the body of the hammer.

What is the difference between rebound hammer test and OPC test?

The use of supersulphated cement in concrete decrease the compressive strength by 50\% compared to that of OPC. The rebound hammer test work best for close texture concrete compared with open texture concrete. Concrete with high honeycombs and no-fines concrete is not suitable to be tested by rebound hammer.