Core sample / core testing The extraction of a small cylindrical column of hardened concrete from a sidewalk to test its thickness and compressive strength in a laboratory.
If the NYC DOT suspects a contractor used subpar materials or skimped on thickness, they may order a core sample test. The extracted cylinder is crushed in a hydraulic press to measure its actual PSI. If the test reveals the concrete is weaker than the required 3,000–4,000 PSI, the property owner may be forced to rip out and replace the new sidewalk.
Frequently Asked Questions About Core sample / core testing
What is core sample testing?
Extracting a cylindrical column of hardened concrete from the finished sidewalk to measure its actual thickness and compressive strength in a laboratory.
When is a core test ordered?
When there is reason to suspect the concrete is thinner or weaker than specified.
What happens if the core fails?
The non-conforming work can be rejected, requiring removal and replacement at the responsible party's expense.
How is the sample tested?
The cylinder is crushed in a hydraulic press to determine the pressure it withstands, reported in PSI.