AGSS Chemical Soil Stabilization: a Cost-Effective Way to Neutralize Expansive Clay Soils

Expansive clay soil causes an extensive amount of damage to roads, walkways, foundations and other structural elements. According to the American Society of Civil Engineers, in a typical year, expansive soil causes greater financial losses to property owners in the U.S. than earthquakes, floods, hurricanes and tornadoes combined.

These statistics are surprising to many people, and that’s probably because the damaging effect of expansive soil typically happens in a gradual manner. Tests have demonstrated that clay can expand in volume by as much as 10% when it absorbs water. In doing so, it can exert as much as 5,500 pounds per square inch of pressure. This pressure can be applied as an uplifting force, as a sideways force, or from multiple directions.

Expansive clay soil has another characteristic that also causes structural damage: It contracts when it dries out. So after pushing up against a sidewalk, slab or wall during wet periods, it shrinks away as the soil dries out, creating voids that can also cause concrete elements to crack and sink. The deep cracks that occur during prolonged dry periods allow for greater water penetration when the weather changes, increasing expansion pressure.

Chemical Stabilization Methods for Expansive Soil

One way to protect foundations, sidewalks and other structures from expansive soils is to improve drainage in the area around them. Basic protective measures like channeling roof runoff away from a building and surrounding a foundation with highly permeable soil have proven to be effective.

However, sometimes it’s not possible to control the amount of moisture that gets into the soil. Roadways, parking lots and airport runways are simply too large to protect with water-management measures. This is where chemical treatment proves to be especially valuable.

As the name implies, chemical soil stabilization works by chemically altering the clay particles in the soil. Because of the mineral composition of clay and silt, these soil elements have a negative surface charge. Consequently, they tend to attract a positive charge, which can be found in water molecules. When clay-rich soil gets wet during rainy weather, water doesn’t pass through the ground like it does in soil that has a high sand and gravel content. Instead, clay particles attract and hold water molecules. The added volume of the retained water causes the soil to expand.

Chemical Ground Stabilization Process

In the chemical soil stabilization process, an ion exchange solution is applied to the soil to reduce the negative charge of clay particles. Once this happens, clay particles will actually repel water, allowing it to drain away.

There are two principle ways to apply the ion exchange solution. It can be sprayed over loose soil and mixed into the soil before the soil is compacted. This technique is often used prior to constructing a road, sidewalk or other slab-type element. A second application method is to drive perforated rods into the soil and inject the stabilizer under pressure. This technique us useful when soil stabilization needs to be done around existing structures, and when clay-rich soil extends to greater depth.

Home/Tract builders, airport taxiways/runways, HOAs, COAs and all new construction have benefited from the ESSL process. When you have an expansive clay soil problem, the AGSS Chemical soil stabilization method is your proven answer.

Foundation Repair California

Polymer injection provides a speedy solution to soil settlement problems

Soil settlement has the potential to stop commerce dead in its tracks. When a section of road, highway or runway sinks, a safe working surface becomes unusable. Such damage also costs the taxpayers millions in broken axles, blown tires and the time and taxes to rip and repour those sunken areas.

A similar disruption occurs when a foundation settles or part of a concrete slab floor breaks away and sinks into a soil depression. Whether this damage happens in a home, factory or commercial building, it demands quick attention to restore both function and safety.

Until recently, foundation repair contractors had to rely on concrete pumping or “mudjacking” techniques to fill voids beneath settled concrete slabs and push settled structural elements back toward their original elevations. But soil settlement problems often go deeper, literally and figuratively. Pumping a cement-based slurry immediately beneath the settled slab doesn’t address unstable soil at greater depths. In fact, the considerable weight of the pumped-in mortar can put more stress on weak soil at greater depths, which causes further settling.
Fortunately, EagleLIFT, Inc. repair specialists now have access to new technology that can stabilize and strengthen soil at different depths, rather than just at shallow depths. This stabilization technique, often referred to as “deep injection,” offers the additional advantage of being fast, affordable, and less intrusive than other solutions. The company that has pioneered this process, Uretek, has provided their patented technical support and injection technology to EagleLIFT, Inc. so that we can offer these specialized services to our customers in California, Arizona and Nevada.


Settlement issues arise when soil load-bearing capacity is limited

Soil is made up of many elements and the characteristics of each element determine how suitable the soil is for different uses. The most desirable soil for load-bearing functions such as roads, runways and building foundations contains high proportions of sand and gravel and much smaller amounts of organic and fill material. Unfortunately, construction often takes place on soil with poor load-bearing qualities. Eventually, structural elements (such as slabs, roadways and airport runways) combine with live loads (vehicles, machinery, aircraft, etc.) to exceed the load-bearing capacity of the soil, and settlement occurs.
Foundation repair specialists are often called in to deal with soil settlement issues, even when they involve roads, runways and structural elements other than foundations. The first things the contractor will do are a site inspection and recommend a soil test to assess soil conditions. In many cases, the URETEK void fill or deep injection method® of polymer injection will be recommended to restore structural integrity and help prevent future damage.


Polymer injection works by flowing, filling and expanding

The effectiveness of the Uretek void fill or deep injection techniques is due to the expansive reaction that takes place when the two chemical compounds are mixed together. The reaction caused through the mixing of the chemicals under the pressure of the soils is extremely strong and can support up to 5 tons per square foot.

Polymer injection can be performed directly beneath a settled structural element, or at depths of 30 ft. or more. Uretek’s proprietary technique of deep soil stabilization is called the Deep Injection Process®. Based on penetrometer tests that assess soil density, technicians establish an injection grid to target specific locations where the polymer must be placed. Holes are drilled in the slab or other structural element according to the injection grid; then a length of tubing is inserted in each hole. Tubing lengths vary based on the different injection depths that have been established.

The 2-part polymer is mixed right at the injection nozzle that’s connected to the tubing. As the resin and catalyst compounds combine, a powerful chemical reaction takes place that causes the liquid mixture to expand as soon as it exits the bottom of the tube. The polymer begins its expansive foaming action as it flows into the soil. Because the expanding material naturally follows the path of least resistance, it flows and fills where it’s needed most to increase soil strength.

The polymer stops expanding as quickly as it started, hardening within a minute or so. Within 15 minutes, it has attained about 90% of its final strength. Experienced technicians can tailor this injection process to lift settled slabs and other structural elements back to their original positions, while also stabilizing the surrounding soil to prevent future settlement. The Uretek Void Fill or Deep Injection Methods can lift and support tremendous loads. Polymer injection is a practical, effective and economic way to solve a wide range of soil settlement problems.