Shrinkage Cracks In Concrete Slab

This restraint creates tensile stresses in the concrete slab which in turn may produce drying shrinkage cracking.

Shrinkage cracks in concrete slab.

Contraction joints or control joints when cracked are really just straight shrinkage cracks. Most of the water will eventually evaporate causing shrinkage of the concrete slab. Concrete and mortar are porous in their structure in the form of inter molecular space. They expand when they absorb the moisture and shrink when they dry.

See details at concrete shrinkage cracks. Shrinkage cracks in concrete occur due to change in moisture of concrete. When that water eventually leaves the slab it leaves behind large voids between the solid particles. Similar uncontrolled or random cracks sometimes due to poor joint layout meander across the surface.

Concrete slab drying shrinkage cracking can be the unfortunate end. Most of this excess water begins to exit the concrete during placement curing and causes the concrete to shrink. As the concrete slab dries after placement it shrinks. Plastic shrinkage concrete cracks when concrete is still in its plastic state before hardening it is full of water.

While the concrete is shrinking many things such as reinforcement or the subgrade restrain the concrete. Plastic shrinkage cracks are common in slabs. This is the main cause of concrete shrinkage cracks on drying. In addition to reading about repairing concrete shrinkage cracks if crack repair is needed at all.

While shrinkage in poured concrete walls or floor slabs is a normal property of curing concrete shrinkage cracks can be controlled or where they have occurred in some cases repairs are needed. Shrinkage cracking can be managed by the use of control joints placed in the slab. When concrete is mixed more water than is needed for hydration is mixed with the dry components such as sand cement and an aggregate. Shrinkage cracks in a slab photo above are unlikely to be of any structural concern but can be a source of water entry or radon entry in buildings and may form a tripping hazard.