How do they get the sample out of concrete?

Question

I know they cut the hole with a long hole saw but how do they cut the bottom of the plug they just cut around?

Answer 1

Concrete has very low tensile strength and without reinforcement steel rods in it, you can break a 2 in dia concrete rod of 2 ft length yourself with your hands.

The core breaks from the bottom once you have drilled long enough with a simple wedging action

Answer 2

Normally they just cut the hole through the concrete slab. But if it has to be a blind hole, it can be cracked off the bottom using a wedge. Tilt the core to one side by smacking a wedge in the slot with a hammer. It takes very little movement to break it.