What causes concrete slab to crack?

Question

What causes concrete slab to crack?

Answer 1

concrete is heavy, and if not supported, can crack under its own weight, a tree root may lift it up and break it, or the soil under may wash away

Answer 2

Concrete slab is supposed to develop hairline cracks over time; it's when the cracks are large that there's a problem.  If the slab was poured and no rebar or wire mesh used within it, you'll have major problems.  Our neighbor's driveway didn't get wire mesh laid down and they've got huge chunks broken off and another large area wanting to give way; all it'll take is for some dirt to wash out.  This happened when a delivery truck drove on their driveway.  A house slab can have structural problems for the same reason, as well as being caused by soil instability.

Answer 3

heat expansion

Answer 4

There are many reasons a concrete slab will crack. 1 Tree roots crack driveways all the time. 2. If the cement dries to quickly it can crack. The longer cement cures the stronger it is. #. The change from hot to cold in the seasons cause concrete to expand and contract which can cause concrete to crack as well. that's why you have the seperations in a sidewalk to help prevent this from happening.

Answer 5

FROM THE LOOKS OF IT YOU HAVE THE BEST ANSWERS ALREADY

THE ONLY ONE I HAVE IS SOMETHING WASN'T DONE RIGHT BEFORE IT WAS POURED

Answer 6

There are a hundred reasons why a slab can crack, one of which can be expansion, another is lack of control joints ( the lines you see in sidewalks and stuff) lack of expansion joints( the really thick lines you see in a sidewalk) lack of compaction of the soil underneath, water intrusion under the slab washing the soil away that supports the slab, placing a heavy weight on the slab that it wasn't designed for like a big truck parking on a side walk designed for people to walk on, and the list goes on and on inferior concrete lack of reinforcement etc. are you getting the idea? Anyone answering this question needs more information

Answer 7

when you salt them in the winter. only salt pavement. use calcium on concrete........................ or a jackhammer

Answer 8

Concrete slabs crack because the expanding and contracting. They expand and contract due to heat changes. They expand when it is hot and contract when it is cold.