How is the strength of concrete measured?

We place an awful lot of trust in concrete. Buildings, walkways, highways…what would this world be without concrete?  We take it for granted; however, concrete plays a major role in our daily lives. To gain an understanding as to how concrete can hold such incredible amounts of weight and last for so long, it helps to know how its strength is measured.

Different ways to measure concrete strength

The traditional and most accurate way

Compressive testing is the surefire way to measure concrete strength. Precisely, a cylindrical specimen is selected for the testing, either 6 by 12 inches in size or 4 by 8 inches. The specimen is placed into the compressor and compressed. The strength is determined by dividing the load at failure by the average cross-sectional area. Ideally, concrete’s compressive strength should range between 2500 psi and 4000 psi. Residential concrete will weigh towards the lower end of psi, while commercial concrete will weigh on the higher end.

Compression testing on existing structures

It’s one thing to test a new batch of concrete, but it’s another to test concrete that is already part of an existing structure. These specific tests either require a careful extract of a concrete specimen or the use of unique measuring tools. Traditional compression testing can still be done, though, it is quite challenging. Part of the concrete structure would have to be prepped and sawed. The professional would have to determine which part of the concrete is safe to be removed, in order to guarantee no damage to the structure itself. Once removed, the compression test can be completed in the same way as previously mentioned. The results from this method are the most accurate, but the riskiest. Of course, only professionals should attempt this method.

Pull out test

Pull out testing consists of attaching a small piece of equipment to an exterior bolt or fixing. The equipment is then pulled to the stress load level to determine its strength. Ultimately, it is similar to the compression test but with a smaller sample. The pull out test is relatively simple to execute; however, it once again requires removing and damaging concrete. Thus, it is also a risky way to measure concrete strength.

Rebound hammer

The use of a rebound hammer is by far the easiest way to measure concrete strength. Though, with it being easy, the readings and result will not be as accurate as the other measuring methods. This particular method involves impacting the concrete with the rebound hammer. That is all there is to it. The hammer is spring driven and a measurement will populate upon the hammer recoil. Again, the measurement will not be as accurate, but it is an indicator as to whether or not the concrete is in good condition. Certain factors can disrupt the rebound hammer’s reading as well. For example, rebar or sub-surface voids will affect the measurement reading. There is a lot more to measuring concrete strength, but we hope you now at least have a general understanding. For all of your concrete needs, Anani Pumping is your top source. Contact Anani Pumping today! Also, please visit our blog for additional news and information.