Slabjacking is a specialty concrete repair technology. In essence, slabjacking attempts to lift a sunken concrete slab by pumping a grout through the concrete, effectively pushing it up from below. The process is also commonly referred to as "mudjacking" and "pressure grouting" as well.
Most of the time a slab can be put back to its original position by pumping a mixture of sand, cement, fly ash, and other additives beneath your slab. Drill strategically placed holes into the slab. Using a portable pump and flexible hoses, the holes are filled with the special mixture. Lifting a slab using this method can often be accomplished in a few hours.