An Oakwood, Georgia corrugated metal pipe rehab job, involving the replacement of the end caps, resulted in soil migration through the new joints. This in turn led to depressions in the asphalt road above. The City of Oakwood public works department called in Atlanta-based geotech specialists LiftitRite to assess and repair the pipe and the soil.

Powerful Polymer

Alchatek's AP Fill 700 was an easy choice for this project. AP Fill 700 is a single-component, water-activated, hydrophobic polyurethane resin that is highly effective in cutting off high-flow underground leaks, filling voids, and stabilizing soil. It is also NSF/ANSI/CAN 61 approved for contact with drinking water.

Painless Procedure

The technicians began by stuffing the larger joints with resin-soaked Oakum to create an impermeable gasket. Then, injection ports were installed adjacent to the joint in a clock pattern. The crew injected AP Fill 700 until the joints were fully sealed and permeation of the surrounding soils was achieved.

Wanting to ensure a “belt and suspenders” repair was done, they opted to inject AP Fill 700 through the top of the road as well via injection probes. The probes were driven down to depths coinciding with the tops and sides of the culvert pipes. These injections ensured that all voids and shifted soils caused by the pipe infiltration were filled, permeated, and stabilized - thus preventing any future road depressions or dropouts.

Rapid Result

City of Oakwood officials were extremely pleased to see this issue remedied in just 2 days via an effective and affordable solution that involved minimal traffic disruption and zero excavation. 

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A general contractor on a new commercial construction job reached out to Atlanta-based geotech contractor SiteMix Pressure Grouting LLC about the foundation phase of a project they were working on.  Sheet pile panels were used for erosion control while they poured the foundation walls.  After the foundation concrete was cured, there was still a layer of gravel and soil being held in place by the sheet pile panels, located between the panels and the foundation.  If the contractor were to pull up the sheet piles without stabilizing that gravel and soil first, it could become unstable, leaving the foundation without a surrounding layer of supporting soil. The soil and gravel would need to be locked in place first before the sheet pile panels were removed. Soil stabilization specialists SiteMix Pressure Grouting LLC were the perfect subcontractors for this job.

Powerful Polymer

The technicians selected Alchemy-Spetec's AP Fill 720 structural polymer for the job due to its ability to permeate the soil and encapsulate the gravel into one solid mass.

Painless Procedure

The crew inserted injection rods to a depth of about 12 feet deep at a spacing ratio of 3 feet apart along the entire length of the foundation wall. Next, they injected the structural polymer until it was seen bubbling up through the surface of the ground (a.k.a. grouted to refusal).

Rapid Result

The entire layer of surrounding supportive soil and gravel was locked into place. When the sheet piles were pulled, only a thin gap from the sheet pile panels remained. The contractor then filled that gap with cement, leaving a solid supportive wall of soil/gravel/grout to support the foundation.

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Geotech specialists from Ground Consolidation Services were called into a job by a general contractor in Atlanta. A property owner was restoring a very interesting pool house in an upscale neighborhood. The pool actually sits atop and in the center of the pool house itself. During the initial restoration process, they discovered voids under the pool house foundation.

Powerful Polymer

The GCS crew recommended Alchemy-Spetec's AP Lift 475, a two-component, hydrophobic, structural lifting polymer designed for airport, highway, and railroad applications. It can be used to stabilize structures, fill voids, and lift slabs supporting tremendous loads. The real beauty of this material is its ability to be traffic ready in less than one hour.

Painless Procedure

The technicians used the compact PolyBadger pump system for this job since the location was not easily accessible with a slab lifting rig. The PolyBadger, manufactured by Alchemy-Spetec, is a tough and compact mobile cart system for pumping polyurethane resin. Using this pump, the crew was able to fill the voids at a relatively quick pace.

Rapid Result

The GCS technicians were out of the way and the restoration crew was able to start backfilling the area in a few short hours.

A property owner reached out to a geotech contractor for help with a leaking retention pond. The pond feeds into a creek via a concrete spillway. Over the years water has worked its way through the earthen dam and under the spillway, causing large voids and soil loss under the concrete.

Powerful Polymer

The technicians selected AP Fill 720 as the repair material for this job. AP Fill 720 is a single-component, closed-cell, hydrophobic, water-reactive, phthalate-free, low-viscosity polyurethane injection resin for cutting off large water leaks and filling voids around structures. This high-strength durable material will react and expand quickly upon contact with water and is one of the top soil stabilizers on the market. 

Painless Procedure

The spillway was about 15 x 15 feet in size, with one 15-foot side bordering the pond. After soil probe testing it was decided that the crew would inject AP Fill 720 directly next to the spillway on the pond side and then directly underneath the spillway via 5/8 inch drill holes in the concrete along the border with the pond. All injections were completed to a depth of four to five feet.

Rapid Result

This project was completed within a day. The AP Fill 720 structural polymer was cured within a couple of hours after injection. The homeowners were thrilled to see their pond system, which they were heavily invested in, finally functioning as it was designed.

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Recently Atlanta-based contractor Sitemix was called in for a highly urgent remedial project at a nearby university apartment building. A plumbing break quickly evolved into a bigger issue than just fixing some pipes. The breach resulted in large voids under the foundation slab that compromised the integrity of the entire structure. Sitemix answered the call and was immediately up to the challenge. 

Powerful Polymer

Alchemy-Spetec’s AP Lift 430 was chosen for the job due to its high density, high expansion rate, high yield, and cure strength. This two-component, high-strength, high-density, hydro-insensitive structural polyurethane foam is ideal for void fill and structural stabilization and void fill in situations like the one described above. AP Lift 430 weighs 2.75 – 3.25 pounds per cubic foot.

Painless Procedure

The structural polymer was injected through the slab to fill the voids and compact any compromised soil.

Rapid Result

The project was completed in a half day while most of the occupants were in class. The GC was ecstatic to have this emergency resolved quickly and painlessly.

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Settling Garage Floor Slab – Causes

As with most slab settling issues, voids and poor soil compaction are at the root of the problem. This is certainly the case with sunken garage slabs. They are typically constructed by backfilling the area after the foundation is poured (or blocked) and pouring the concrete on top. Achieving proper and adequate compaction is often difficult and just not achieved in many cases. This, combined with time and freeze/thaw cycles creates voids under the garage slab. Concrete itself is heavy and can settle, but when we park vehicles on top of a garage slab that has voids under it? It is obviously a recipe for disaster!

Settling Garage Floor Slab – Solution

Alchemy-Spetec can refer you to a contractor for a thorough site evaluation. A qualified contractor takes the time to properly inspect the issue, which generally entails probing the slab to determine if there is indeed a void and/or unstable soil (and to what extent). Gathering this type of information is key to designing a proper repair plan and calculating the amount of polyurethane lifting material needed.

Depending on the conditions found during site evaluation, there are a couple of different techniques the contactor may use (and oftentimes both). If the soil under the garage slab is soft and unstable to a certain depth, they may opt for the Deep Lift® method. The expanding structural foam creates a squeeze effect in the loose soil, essentially forming added support footings under the slab. The other injection method, Slab Lifting, entails going through ⅜-inch holes drilled directly through the slab. The same structural foam described above is used. The expanding foam travels the path of least resistance, therefore, filling all void areas as well as compacting any loose soil. Once the soil is compact, the expansion of the foam creates the power to lift the slab. Our high-density polyurethane cures to 90% in fifteen minutes – which translates to the slab being traffic-ready by the time we are packing up our equipment.

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