Slabjacking (also referred to as Mud-Jacking, concrete lifting or concrete leveling) is a construction procedure that is designed to correct sunken concrete slabs or roadways. This manual contains basic information that can be used when determining the best methods for correcting a slab defect. In no case should this manual be considered all-inclusive, but it does represent a strong basis of industry knowledge. All concrete slabs and roadways depend on the subgrade base materials to provide a solid bed for the concrete to rest on. When this bed is disturbed, the useful life of the concrete can be severely shortened. The most common disturbance occurs when water migrates under a concrete slab and compacts or removes the base materials. In some cases concrete has been poured over unacceptable materials or materials that were not properly compacted. When base materials are disturbed or removed, voids develop under the concrete. If left uncorrected, the concrete can drop and/or crack. Slabjacking is used to repair damaged slabs resulting from these conditions.
Slabjacking can be traced back over seventy years. Pressure injection for raising deteriorated slabs and roadways got its start in the early 1930’s. J.W. Poulter is credited for developing in 1933 what can be considered the first specialized machine for Slabjacking. This early pioneer in what was referred to then as mud-jacking, developed his machine primarily to correct the faults found at joints on roadways and major highways. The problem of water getting under and through the joints caused a pumping action when vehicles passed from one slab to the next.