Curling is the upward (or occasionally downward) warping of a slab’s edges or corners, caused by a difference in moisture or temperature between the top and bottom of the concrete.
In depth
As a slab cures and ages, the top surface often dries and cools faster than the bottom. The top shrinks relative to the bottom, and the edges lift, curling the slab. Curled edges leave the corners unsupported, so they crack under load and create small changes in level at joints, and the gap beneath the raised edge is itself a void.
Curling is primarily a concrete-behavior issue, but because it lifts edges off their support, void filling and joint stabilization are often used to restore contact beneath the curled areas and prevent cracking.
How Acme applies it. Where curling has left edges unsupported, Acme’s void filling and joint stabilization can fill the gap beneath the slab so the concrete regains uniform support.
Related terms: Under-Slab Void, Rocking Slab, Concrete Cracking, Expansion Joint
Frequently asked questions
What causes a slab to curl?
A moisture or temperature difference between the top and bottom of the slab makes one face shrink more than the other, lifting the edges or corners.
Can curled slab edges be stabilized?
Yes. Filling the void beneath a curled edge and stabilizing the joint restores support so the unsupported corner no longer cracks or moves under load.