Slabjacking (mudjacking)
Lifting a settled concrete slab back to grade by pumping grout or expanding polyurethane foam through small holes drilled into it.
What does slabjacking (mudjacking) mean?
The technique fills the void beneath the slab and raises it, which is far cheaper than removal and replacement when the concrete itself is sound. Traditional mudjacking uses a cementitious slurry, while polyurethane foam is lighter, cures in minutes, and requires smaller holes. It corrects elevation but does not repair broken slabs or fix the drainage problem that caused the settlement.
In practice
A sunken sidewalk panel or a settled garage apron is a good candidate; a slab broken into six pieces is not.