An industrial floor slab on grade should be durable, free of excessive cracking, and suitably flat and strong enough for the traffic it must carry. Achieving all this takes consultation among the slab designer, owner, soils technologist, and the builder.
A quality industrial floor on grade requires a well drained, uniform subgrade of adequate bearing capacity. Gravels and gravel-sand mixtures have high bearing capacity. Bearing capacity of a weak subgrade can be improved by drainage, compaction, or soil stabilization.
Here's where accurate information from the owner is essential. He must provide information on: forklift trucks or other traffic loads; storage loads; post loads; building column loads.
CHOOSING THE TYPE OF SLAB: REINFORCED OR UNREINFORCED
The common types of industrial slabs on grade are: unreinforced ordinary portland cement concrete; reinforced ordinary portland cement concrete; shrinkage compensating cement concrete with reinforcement; and post-tensioned concrete.
Careful joint design and location are essential to a trouble-free floor. Control joints are provided to take care of concrete shrinkage. Maximum spacing between joints depends primarily on subgrade friction, slab thickness, whether or not there is reinforcement, and what shrinkage can be expected in the concrete.