Slab Stabilization Slab stabilization consists of pumping a grout through holes drilled through the slab surface, in order to fill voids beneath the concrete pavement slab or base layers. The voids usually occur near cracks, joints, or along the pavement edge, and are often not more than 1/8 inches deep. Slab stabilization should not be confused with slab jacking, which is done to raise depressed slabs. Several common destructive forces cause these voids. Heavy traffic loads induce the highest slab deflections near transverse joints and working cracks. These deflections may cause pumping, consolidation, and loss of the subbase or subgrade support. Without support underneath the slab, load stresses in the concrete increase and may cause other problems, such as faulting, corner breaks, and cracking.