Industrial floors crack mainly because of poor compaction below the slab, joints that are missing or cut late, loads the floor was never designed for, or poor curing. To avoid it, give the designer real racking, forklift and machine loads, compact the sub-grade in layers, use a proper base, cut and seal joints on time, and cure the slab fully.
1. State the real loads
Racking leg loads, forklift wheel loads and machine weights should be given to the designer. A floor specified only by thickness is a guess.
2. Compact what is underneath
Filled soil that was not compacted in layers will settle, and the slab will crack above it. Compaction is the cheapest insurance a floor has.
3. Base and membrane
A proper base layer, and a membrane where specified, give the slab uniform support.
4. Joints in the right place, at the right time
Concrete shrinks as it dries. Joints cut at the right spacing and time make it crack where you want, in a straight line you can seal.
5. Cure properly
A slab that dries too fast loses surface strength and starts dusting. Curing time must be in the schedule.
6. Plan around machines and pits
Machine foundations and pits should be isolated from the floor slab so vibration and settlement do not crack it.