PRESSURE GROUTING

Pressure grouting involves the injection of a liquefied cementitious material, under pressure, into large voids, void spaces between soil particles, cracks, or even between subsurface bearing materials and an existing structure. This technique is used to apply pressures on adjacent soil formations or building structures as in floor or foundation leveling. The process further requires that the grout gel or solidify within the areas treated. Pressure grouting can take the form of compaction grouting, curtain grouting, chemical grouting, permeation grouting or any other application where the grout material is installed under pressure.

COMPACTION GROUTING

Compaction grouting improves the bearing capacity of foundations and underlying soils by pumping a low-slump cement mixture into the soil, under pressure. The cement pushes aside the surrounding soil as it is pumped in, compacting the soil in the process and increasing its density, while forming a grout column or bulb. The method is thus simple in essence but requires careful planning based on a knowledge of onsite conditions to achieve best results at a given location.

CHEMICAL GROUTING

Chemical grouts an efficient and cost-effective means to bind in-situ soil particles and seal narrow joints, fractures, and seeps. Chemical grout is forced through joints and cracks into the surrounding soil where it solidifies with the soil to form a relatively impermeable mass. The process requires injection of a specially formulated fluid grout (typically sodium silicates, acrylates, polyurethanes or MC-Silicates) into existing pore spaces in finer-grained soils suh as silts and clays that resist penetration by cement. Various chemical grouts have different strengths, viscosities, toxicities, and costs.

CEMENT (SLURRY) GROUTING

Cement or slurry grouting is the pressurized injection of flowable particulate grouts ("flowable fill") into open cracks, voids and expanded fractures. Applications include injection into abandoned pipelines, pressure-injected anchors, stabilization of gravels and shot rock, rock foundation treatment for dams and, under proper conditions, confinement of plumes resulting from hazardous waste spills. The materials composing slurry grouting include finely ground slag or Portland cement, dispersants and large quantities of water to form a slurry mixture capable of penetrating fine sand or finely cracked rock.