Specialty Grouting

Compaction grouting is the high-pressure injection of a thick immobile grout into subsurface soils. Because of high grout viscosity, the grout expands radially as a homogenous bulb from the injection point instead of permeating into the soil pores. Compaction grouting is suitable for reducing the potential for soil liquefaction, for arresting foundational settlement, and for lifting and leveling structures.

Permeation grouts are placed into the soil void spaces by low and high-pressure injection through boreholes. A stabilizer can be added to the grout controls set time. The grout bonds with the soil particles, producing a composite with higher shear and compressive strengths than the un-grouted formation. Permeation grouting does not use mechanical means to restructure the soil in the process. The soil structure remains relatively undisturbed. Consequently, the operation creates minimal ground disturbances and better ensures against adverse deformation and damage to the ground formation.

Annular Space Grouting is process of filling the space between a host pipe or box culvert and a new liner pipe or conduit that has been pre-installed, better known as “slip lining”. Many state and federal transportation projects have been done utilizing this trenchless method with time and cost savings.

Polyurethane injection is most commonly used for water control by injection into cracks or joints to form a gasket, and by injection through a structure to form a barrier between structure and soil, or by injection into the soil to consolidate the soil into a monolithic, impermeable barrier.

Polyurethane resins or grouts form gels, foams or solids, and are hydrophilic or hydrophobic. They are very stable, and have good resistance to acids and alkalis. Life expectancy of polyurethanes can be measured in one to two decades. These resins have many desirable qualities, such as expansiveness, adherence to wet or dry surfaces, controllable set times, a tenacious bonding ability, chemical resistance, and are reacted by the very water that you may be trying to stop.

MCSI has been using polyurethane resins since the late 90’s, and in many different types of applications, including soil stabilization and injection into rock strata, dams, water tanks, water treatment plants, pools, and basements.

Chemical grouts constitute the other branch of permeation grouts. Like the cement grouts, the chemical grouts enter the soil by penetration. However, chemical grouts can penetrate into finer grained soils otherwise inaccessible to cement grouts. The primary design objectives of chemical grouts are ground improvement and water seepage retardation.

Cement grouts contain water and Type I or Type II Portland cement. Cement grout properties are variable. They can be altered by using other cement types, such as Type III (high early strength), Type IV (low heat of reaction), or Type V (resistance to chemical attack). Varying the water to cement ratio changes the grout’s bleeding rate, subsequent plasticity, and ultimate strength.

Mixing in an additive, such as bentonite, sodium silicate (a chemical grout), dispersants, retarders, and accelerators, will also alter grout properties and can be engineered for a specific desired goal.