Originally Posted By: mcyr
This post was automatically imported from our archived forum.
In this type slab I would recommend cutting the slab control joints as close to a ten foot square as possible considering all the pipe penertrations and bond outs that I see.
Any time you create a bond out or a round penatration, the slab will relieve it's shinkage in those locations.
It can be possible to deviate from the ten foot parameter and locate the cuts under partion walls and aim as much as possible to pipes and/or bond outs. This way the cuts will be concealed and not be as visible to also impair floor coverings.
In my area it is also recommended to use 3000 PSI concrete with no air-entrainment. This seems to eleviate the slab curls normally seen at control joints and construction joints.
My concept of slab curl would be to seal the sawed control joints as soon as possible, because when the slab dose release, the air flows down under the slab and induces the slab curl syndrome. I have not proven this yet, but someone will eventually. When air flows to the underside of a concrete floor to meet the moist surface, it tends to dry like the surface and reacts like the dry surface, and tends to force upwards creating a curl and hump in the floor at the construction or control joint.
Remedial work for the flooring applications can be costly and time consumming.
Hope this helps.