This procedure I came across in one of the site.Just for info to Beginners. This test is called WINSOR probe test.
When the concrete is done and its up and you want to know the strength of concrete with minimum damage,this is the one of the test.
Engineer will select the location.In this case its in column.
They use this tool to drive the bolt type into the concrete. Then use a tool to measure the up stand length,from that you can get the penetration depth.Through the depth of penetration the concrete strength is being calculate.
This is on slab.
Take 3 points and take average depth to get the strength.
If you have a query, you can ask a question here.