Shrinkage crack A shrinkage crack is a crack caused by the natural reduction in concrete volume as excess water evaporates during curing. These cracks often appear shortly after placement.
Concrete shrinks slightly as it hardens, and this natural process can create cracking if internal stresses exceed the material's tensile strength. Proper joint placement, curing practices, and mix design help reduce the likelihood of significant shrinkage cracking. Most shrinkage cracks are non-structural, but wider cracks should be evaluated.
Frequently Asked Questions About Shrinkage crack
What is a shrinkage crack?
A crack caused by the natural reduction in concrete volume as excess water evaporates during curing. These appear shortly after placement.
Why does concrete crack while curing?
As it shrinks, internal tensile stresses build. If they exceed the concrete's tensile strength before it is fully hardened, it cracks.
How is shrinkage cracking minimized?
Correct joint placement and spacing, a controlled water-cement ratio, and proper curing that slows moisture loss.
Are shrinkage cracks serious?
Most are non-structural. Wider cracks, or cracks that go through the slab and open over time, should be evaluated.