Serving the Southeast: North and South Carolina, Georgia, Tennessee and Virginia
Foundation Repair Services, Inc. performs several types of grouting services.
Pressure grouting, also called slab jacking, is done by drilling small holes, typically 1" to 2", through a concrete slab and pumping a cementitious grout under the slab to fill voids underneath. While the grout is still fluid, pressure is applied to the grout, creating a hydraulic lifting effect and thus raising the slab upward.
Compaction grouting is a process in which a very stiff, low-slump cementitious grout mix is injected deep into the subgrade soil to densify or compact soft subgrade soil in place. It is most effective in well-drained soils (e.g., sandy soils) and at deeper depths. For the most part, it does not work very well in highly cohesive soils (e.g., clay soils) or at shallow depths.
With fracture grouting, a very fluid, high-slump cementitious grout is injected into soft subgrade soil to improve bearing capacity. The grout is placed by applying enough pumping pressure to fracture the soils. The grout is then free to flow where it finds weak veins or voids. Fracture grouting is typically the only type of grouting that can be effective in high-clay soils, which are common in North Carolina and South Carolina; however, it has several limitations and can have unpredictable results. Surface heave and uncontrolled grout travel can limit the success of the overall grouting program.
Permeation grouting involves pumping a very thin grout through the subgrade strata to increase the bearing capacity by filling all the void space and densifying the soil. In order for permeation grouting to be effective, the subgrade must contain enough void space so that the grout can penetrate the strata. The grout itself must also be thin enough to permeate the soil.
Sands and gravels are easily permeated, but clay soils typically cannot be permeated. The grout used for permeation grouting can be cementitious, such as microfine cement, or it can be a chemical such as a urethane-based grout.
Chemical grouting refers to performing any of the above-mentioned grouting techniques using a chemical or urethane based grout rather than a cementitious grout. This process can be used for cutting off water as well as structural applications.