By Rick Stone, In-house Engineer/Project Executive, Madison Concrete Construction
Concrete is known for its strength and resilience. At Madison Concrete, we take pride in pushing the envelope to build concrete structures that are bigger, stronger and more beautiful than ever. One way to ensure our projects meet and exceed strength requirements is through concrete cylinder testing.
Concrete test cylinders are vitally important in verifying the compressive strength of concrete. The process includes molding multiple cylinders from a fresh sample of concrete, curing them in standard conditions and testing them when they reach a certain age (usually 28 days.) All of this must be done in accordance with ASTM International standards.
But are these cylinders as strong as the in-place concrete they represent? It all depends on how they were handled, cured and tested.
Out of every 100 tests, you can expect one or two cylinders to fail simply due to variability. However, other factors can lead to low-strength cylinders through no fault of the placed concrete. They include reused molds, test cylinders left out in the sun or too close to radiant heating while curing, and even inaccurate testing machines.
In fact, Concrete Construction magazine recently reported that some curing methods allowed by ASTM C 31, Standard Practice for Making and Curing Concrete Test Specimens in the Field, may also lead to low-strength cylinders. (The article recommends immersing cylinders in water during the first 24 hours of curing.)
Low-strength cylinders can result in rejected concrete, delayed construction and expensive investigations into the strength of structures. To avoid such complications, it’s best to ensure cylinders are created and handled correctly from the beginning. We do this, first and foremost, by making sure that the testing technician who will make and cure the cylinders is properly trained and certified by the American Concrete Institute.
Madison has been delivering quality concrete construction for more than four decades. Let us know how we can use our experience to assist you in your projects.