Fundamental to healthy concrete is a solid substrate. Well-compacted soils provide a foundation upon which concrete structures perform. Over time, forces of nature take their toll. Decomposing soils, erosion, freeze-thaw cycles and groundwater migration can break down this foundation. This is the root cause for the damage or failure of many structures, from buildings to highways.

Injecting polyurethane resins and gels into loose or less dense soils, voids, pores and fissures will strengthen the earthen substrate and provide watertight encapsulation. Prime Resins has been providing soil stabilization solutions for more than 20 years with our Prime Flex polyurethane foams and gels. The techniques and products used depend on what you are trying to accomplish, the type of substrate you are working with and what type of equipment you have available.

Typical structures around or under which soil stabilization may be required include:


• Roadways/Highways • Tunnels
• Storm sewer pipes • Bridges
• Catch basins • Seawalls
• Airport runways • Dams
• Driveways • Patios/Walkways
• Foundations • Pools
• Porches • Tanks
• Railroad tracks • Elevator pits

There are many benefits of using chemical grouts vs substrate replacement or excavation repair:

  • Faster
  • Less disruption
  • Less expensive
  • Less environmental impact
  • Safer
  • Permanent

Permeation Grouting // Compaction Grouting // Void Filling

Soil stabilization solutions generally fall into three areas: permeation grouting, compaction grouting and void filling.

Permeation Grouting

Permeation grouting is typically defined as the flow of a low viscosity grout into the pores of the soil without displacing or changing the soil structure. The characteristics of the ground are modified with the activation of the grout into a foam or gel. This serves two purposes:
• to increase the strength and cohesion of granular soils, increasing its load-bearing capacity
• to decrease the permeability of the soil

Migration of water through poor or loose soil substrates (sandy soils, poorly compacted fill, decaying organic matter, etc.) results in erosion, movement and/or loss of soils causing failure in above- and below-grade structures such as slabs, foundations, roadways and bridges. Permeation grouting is usually the solution for these situations. A low dose of catalyst is used slowing down the reaction, which allows the material to permeate loosely compacted soil. The resin is normally injected through small diameter pipes or “probes.”

Compaction Grouting

Compaction grouting is a process by which rapidly expanding chemical grout (fully expanded in 30-60 seconds) is injected through probes into the ground. (One such process is currently under patent: US6634831 B2.) The foam fills voids in the immediate area, fractures the soil with lenses and veins of resins, and compacts the surrounding soil using expansive pressure. Where soil has eroded or settled underneath concrete, resulting in uneven or unstable slabs, is often a situation that calls for compaction grouting in advance of slab lifting.

Void Filling

Erosion, settling soils and decaying material can result in voids around or underneath structures, undermining their integrity and potentially leading to damaged structures. Voids can be quickly and cost-effectively filled with our Prime Flex 985 series of products. These structural foam resins are injected using a two-component pump. The Prime Flex 985 will flow into the voids and cavities and fill them by expanding up to 20 times (depending on formulation). The rigid foam re-establishes contact between the slab and the sub-grade and is strong enough for heavy traffic loads within 15 minutes.

In highway projects, roadways can often remain open to traffic.

Please feel free to call a technical consultant at Prime Resins to assist you in selecting the right solution for your situation. We offer the industry’s best technical support 24/7 if you have questions during your job: 1-800-321-7212.



Product Properties

Permeation Grouting Prime Flex 910 Hydrophobic, polyurethane, extra low viscosity, variable set time
Prime Flex 920 Hydrophobic, polyurethane, low viscosity, variable set time, NSF/ANSI 61 compliant
Hydro Gel SX Hydrophilic, polyurethane, extra low viscosity, single-component, NSF/ANSI 61 compliant
Compaction Grouting Precision Lift 4.0 Hydro insensitive, polyurethane, two-component, set time adjustable with additives
Precision Lift 4.75 Hydro insensitive, polyurethane, two-component, set time adjustable with additives (stronger formulation than 4.0)
Rock Grout 9200 Polyurethane, very low viscosity, two-component, watertight, rock consolidation
Void Filling Prime Flex 985 LX10 Hydrophobic, polyurethane, low viscosity, two-component, ideal for wet conditions
Prime Flex 985 LX20 Hydrophobic, polyurethane, low viscosity, two-component, ideal for wet conditions. Double the expansion capacity of 985 LX10. Certified NSF/ANSI 61 compliant.
Prime Flex 985 5.0 Hydro insensitive, polyurethane, low viscosity, two-component, high strength/ high density, bonds with concrete
AR 800 Hydrophilic, acrylate (acrylamide-free), super low viscosity, low toxicity, elastomeric gel, NSF/ANSI 61 compliant, primarily for geotechnical applications


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