permeation grouting slide

Permeation Grouting

Increase stability, reduce permeability.

How Permeation Grouting Works

The goal of permeation grouting is for the selected grout to permeate the soils, binding the individual soil particles together to increase the bearing capacity and reduce mobility and permeability of the treated zone. CJGeo performs permeation grouting using chemical grouts, including expansive resins, non-expansive resins, and acrylic grouts.

Prepolymer grouts tend to provide the highest compressive strengths within the treated mass, however are higher viscosity, so best utilized in larger grained soils such as gravels and sands. Acrylic grouts can be used in sands, silts, and to a limited amount in clays, and are primarily utilized to reduce soil mobility and groundwater permeability.

Prepolymer Permeation Grouting

Prepolymer chemical grouts are particularly advantageous for grouting gravels and course sands. Typically around 200 centipoise, they are not well suited for injection into find sands or silts, but have excellent mobility in courser grained soils. Sand treated with prepolymer chemical grouts can achieve unconfined compressive strengths greater than 1000psi.

Mobility of prepolymers can be controlled by varying the dosage of catalyst. Prepolymer permeation grouts react with existing moisture in the ground, and generally expand a few times their liquid volume, which allows for reducing the amount of material needed to treat a given volume of soil.

Prepolymer grouts are also excellent for addressing high velocity water flows through soils without washing out, as the reaction time can be set to be nearly instantaneous from contact with groundwater.

Acrylic Permeation Grouting

Acrylic grouts are exceptionally low viscosity–they can be difficult to distinguish from water. Because of this, acrylic grouts are know for their ability to very uniformly permeate fine grained soils. Similar to prepolymers, acrylic grout set times can be easily adjusted by varying the catalyst dosage.

In place, acrylic grouts range from the consistency of a cooked egg white to a hard silicone rubber.

Advantages of Permeation Grouting

Permeation grouting is an excellent alternative to deep foundation repairs in the case of unconsolidated granular soils below concrete slabs and foundations. Chemical grouting soil stabilization is generally paired with a shallow foundation repair such as polyurethane grouting in the case of settlement. Compared to deep foundation repairs, chemical grout soil stabilization is:

Cleaner

Permeation grouting is performed with compact, electrically-powered equipment. Dustless drilling is easily accomplished for interior applications, and mechanical connections in all components of the injection equipment ensure no loose material.

Less Disruptive

Compared to underpinning, permeation grouting is phenomenally less disruptive. Typical deep foundation repairs require 8″ diameter holes drilled through floors, and large access pits dug next to foundations. Deep soil stabilization only requires 1 5/8″ access holes drilled through floors and 3/8″ diameter injection pipes driven into the soil to be treated.

Faster

Permeation grouting is generally faster than underpinning repairs or other deep grout injection processes due to its compact equipment and ease of installation. Because of its compact equipment, fast reaction times and minimal surface disruption, work can easily be scheduled and planned to accommodate an area’s or structure’s normal use.

Speak With An Expert

Facing a challenge? Give us a shout or shoot us a text.

Kirk Roberts, d: 804-404-2683

Top