Rebound Hammer

[97EOs]

Does anyone own a Rebound Hammer? Have you tried testing it on a 1000 psi, 2000 psi, 3000 psi, 4000 psi, 5000 psi concrete to see if the results correlate supposing the surface is even and representative of the concrete? I saw it done and it seems to correlate somewhat.

 

[Ron]

I have used a rebound hammer many times. I've also seen it used incorrectly many times by others...both in the actual use and the interpretation of the results.

The rebound hammer is only good to determine the consistency of the concrete in a given area. Do not use it to determine compressive strength of in place concrete. Yes, there is a scale on the side that gives a correlation....do not rely on it.

A rebound hammer is susceptible to error in the readings based on surface preparation of the test area prior to testing, the type and size of coarse aggregate, the angle of "attack" of the hammer face, etc. Read the first page of the ASTM procedure for using a rebound hammer...it will tell you not to use it for compressive strength testing.

 

[Splitrings]

The hammer gives an "indication" of in place strength. ASTM C805 states this.

The ASTM requires you correlate the rebound number to core samples to estimate in place strengths.