Alchatek Blog

This is where it all started. At a new solar field installation in North Florida, there were areas of bad soil where the H piles were not passing the loading and pull testing. Solar panels lie at an angle, so a strong wind from one direction can try to “lift” the panel and pile. A strong wind from the opposite direction creates a downward force that can drive the supporting pile into the soil.

Powerful Polymers

The general contractor, Stable Soils of Florida, contacted a local grouting specialist and asked if they could use cement grout to lock the piles into place. Because of the tight confines between rows of piles, the specialist suggested a chemical permeation grout: AP Soil 600 polyurethane grout. The equipment is more compact, and it is much cleaner to install than cement.

Painless Procedures

At the Alchatek plant where this resin is made, we set up a small demo (shown above). A steel C-channel was embedded in sand. AP Soil 600 was poured on top of the sand and allowed to soak in by gravity. AP Soil 600 is moisture activated (the same as Gorilla Glue), but it only takes about 5% moisture in the soil to make it react. In this case, we wet the sand slightly.

AP Soil 600 is heavier than water by design, and it is also hydrophobic. As it soaks in, it pushes through the moisture and displaces it. Once it cures, the sand is locked together.

Rapid Results

As AP Soil 600 soaks into the damp sand, it reacts and produces carbon dioxide. The CO₂ creates a swelling effect that drives the resin further into the sandy soil. In the image above, you can see the CO₂ starting to bubble.

Below is the finished result after the bucket was removed. We beat on the permeated sand with a 5 lb sledgehammer to see if we could break it off the C-channel. Because it is a resin, it is very tough, and we could not dislodge it from the steel.

Around 20 test piles were installed at the solar field. AP Soil 600 was injected right against the steel at a depth between 3 and 4 feet, with injection volumes varied across the test piles to establish the right rate for the site. All of the piles passed the pull testing and compression testing. The project was awarded, and around 4,000 piles were injected in total. It was a complete success.

Aerial view of the FPL Sunshine Gateway Energy Center after it was completed in 2018.

Fast forward to 2022 at a massive solar field installation in Ft. Green, Florida. Like many solar fields, it wasn’t built on the best land. The site was a filled-in phosphate mine, so the soil was layered with bands of clay, sand, and mine tailings. Once again, there were sections of the solar field where the piles were not passing the pull testing, load testing, and lateral testing.

Polyurethane grouting was proposed, but the manufacturer of the components (Sol Components from California) wanted the proposed polyurethane material to go through more vetting. Primarily, they wanted to know if the polyurethane grout would last for the 25-year service lifespan of the solar field. Job histories, accelerated testing results, and chemical resistance data were provided, to their satisfaction.

For this project, the owners wanted engineers involved in the grouting portion of the install. Mathers Engineering was in charge, and they contracted Madrid Engineering to handle the soil testing. Testing showed layers of clay and sand (referred to as zebra striping), so the grout was targeted in the sandy areas. The thinking was that the permeated sand would be locked in between layers of clay, improving both compression and pull strength.

As on the first project, test piles were injected at a range of volumes, and the engineers confirmed the injection rate that consistently passed testing. That rate was used for production. 5,000 piles were injected on this project, about 90% of them with AP Soil 600. There were some areas of organic soils, and for those, AP Fill 700 was injected and tested successfully. AP Fill 700 has over 30X expansion and works well at improving organic soils. The work was completed in the spring of 2022, and the solar field went into service.

In the fall of 2022, disaster struck Ft. Green, a location unfortunately positioned directly in the path of a Category 3 hurricane. The storm left a trail of destruction in its wake. Trees were toppled, and the solar field, designed to endure winds exceeding 100 MPH, faced unprecedented damage. The wind from the hurricane’s eyewall drove the piles of solar panels into the ground. Many panels were shredded, and a significant number of piles suffered movement.

Out of 5,000 piles injected, only 9 showed any sign of movement. The polyurethane grout was put to the test and passed with flying colors. The repair method has already been tested: the embedded piles were jacked back up to level and then grouted in place with AP Soil 600, and all of them passed. The field is now waiting for the insurance process to be completed so the rest of the damaged piles can be locked back into place.

AP Soil 600 carries the NSF / ANSI 61 rating. It is safe for contact with potable water, and in this application, it will not leach any chemicals into the soil or groundwater.

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For warehouse and distribution-center operators, facility and property managers, shipping and logistics managers, and the contractors who serve them: what a sunken loading dock or ramp slab really costs to fix, why it keeps getting worse, and why lifting often beats replacing it.

A sunken loading dock or ramp slab does not fail all at once. It drops a fraction of an inch at a time: a lip at the dock door, a dip in the apron where the trailers line up, a drive-up ramp that slowly pulls away from level. By the time it is obvious enough to put on a work order, the slab is no longer the only cost. The cost of a sunken loading dock or ramp slab is measured in forklift and trailer downtime, damaged product, a dock leveler that no longer seats against the trailer, and the liability of a trip hazard in the busiest few feet of the building. Every one of those climbs while the concrete sits.

Here is what the numbers actually look like, and why lifting the slab may very well be more effective than replacing it.

What Causes a Loading Dock or Ramp Slab to Sink

The slab itself is rarely the problem. What fails is the ground underneath it, and a loading dock sits on some of the most vulnerable ground on the whole site. A raised dock is built on deep engineered fill placed behind the dock wall during construction. If that fill was never compacted to spec, it keeps consolidating for years, under its own weight and under everything that drives over it.

Water makes it worse, and the apron is exactly where water collects. Roof downspouts, trailer wash-down, and poor site drainage all concentrate runoff where the trucks park. Moving water carries the fines out of the subgrade and leaves voids behind. Once a void opens, the slab is spanning empty space instead of bearing on soil.

Then there is the load. A dock apron and a drive-up ramp take the heaviest, most repetitive loads in the building: fully weighted trucks, loaded forklifts, and trailer jacks hitting the same few feet of concrete thousands of times a year. Over a void, that traffic pumps the slab like a see-saw, driving it further out of level with every pass, chipping the joints and widening the gap underneath. On a ramp, even a small drop changes the slope and the approach angle. At the door, it drops the slab below the dock leveler, so the plate no longer meets the trailer bed and loads have to bridge a lip. The settlement does not stabilize on its own, because the loads that caused it come back every shift.

Why Patching the Lip Doesn't Last

Grinding the lip, feathering an asphalt patch, or pouring a thin cap all improve the surface for a while, which is why they are usually the first response. But a patch sits on the same unsupported base that let the slab drop in the first place. The void is still there, the traffic is still there, and within a season or two the patch cracks and the lip comes back.

There is a liability cost to the cosmetic fix as well. Under the ADA, a vertical change at a walking surface as small as a quarter inch is treated as a trip hazard that has to be corrected, and a loading dock is a pedestrian work area as much as an equipment lane. Painting or patching a known lip without addressing the cause can later be used to show that the owner knew about the hazard and chose not to resolve it. The repair has to reach the soil, not just the surface.

Cost of Inaction vs. Repairing It Right

The slab repair is the smallest number in this whole conversation. The expensive options are doing nothing and replacing the slab.

Read the first two rows together. The replacement figure is for the concrete alone. The real number is that price plus demolition, disposal, and the days or weeks the dock sits closed while new concrete cures. Lifting is an all-in number measured in hours, with the dock back in service the same shift. For a facility that ships on a schedule, the downtime difference by itself is often larger than the entire repair invoice.

There is also a cost that does not show up on any repair estimate: a forklift accident. Forklift incidents are among the leading causes of death in warehouse environments, and a loading dock or ramp is where that risk concentrates. The danger is not always something a driver can see. A sunken slab or a ramp that no longer meets the dock is at least visible. The more dangerous case is a slab that has not settled at all but has a large void beneath it. It looks level and sound, right up until the weight of a loaded forklift finds the hollow underneath. We have seen forklifts break through slabs that showed no settlement whatsoever, only an empty void below. By the time the surface gives way, the cost is no longer a repair bill. It is an injury, a stopped operation, and a liability claim.

Why Contractors Use Alchatek for This

Stopping the problem means filling the voids and raising the slab without piling more weight onto soil that already failed, which is exactly what structural polyurethane lifting foam does. Alchatek's AP Lift foams are injected as a liquid through small holes drilled in the slab, then expand to fill the voids underneath and raise the concrete back to grade in a controlled, measurable way. For the heavy, repeated loads a dock apron and ramp take, a high-density product such as AP Lift 475 carries the weight. Where the fill behind the dock wall has failed at depth, that soil can be stabilized several feet down with the Deep Lock® process before the slab is ever lifted.

• Minimal disruption: a small jobsite footprint lets the dock keep working around the repair.
• Minimal downtime: traffic-ready in minutes, not days.
• No added weight on weak soil: the foam is a fraction of the weight of the slurry used in old-style mudjacking, so it does not re-load the ground that gave way.
• Precision: the slab is raised in stages and checked to grade, so the dock leveler seats again and the approach comes back smooth instead of overcorrected.

The positioning Alchatek gives its contractors is the one running through this whole article. You are not selling a few drum sets of foam. You are selling the operator their dock back: level, load-ready, and shipping again the same shift.

Continue Reading

• What Does a Settled Concrete Slab in a Warehouse Actually Cost?
• Foam Concrete Lifting: A Durable Solution for Sunken Slabs
• Sinking Concrete Slabs: Causes and Solutions

Get the Dock Back in Service

The cheapest time to lift a sunken dock or ramp slab is before the void spreads and the leveler drifts out of alignment. Talk to an Alchatek specialist at (404) 618-0438, or find a trained contractor near you.

Cost ranges in this article are industry averages drawn from published 2025–2026 concrete-leveling and slab-replacement cost guides. Figures represent typical repair and replacement pricing, not a quote; actual costs vary by site conditions, region, slab thickness, load, drainage, access, and severity.

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The Clearwater Fire Station faced a growing infrastructure threat. Cracks began appearing across the asphalt driveway leading into the station, a critical access route used daily by emergency vehicles.

These surface defects were symptoms of a deeper problem: void formation and soil loss beneath the roadway caused by a compromised storm drain system. The underground piping was deteriorating, with gaps in storm drain seams allowing surrounding soil to wash into the system during heavy rain. Over time, this erosion created voids beneath the pavement, jeopardizing both the integrity of the roadway and the safety of emergency operations.

Leadership at the station knew a surface patch was not enough. The solution had to address the underlying soil instability and protect the structure long-term.

Initial Assessment

Stabilizing a storm drain without full excavation is a technical and precision-driven task. Three constraints shaped the approach:

• Access. The fire station driveway had to remain operational for emergency vehicles.
• Material placement control. Injection had to reinforce the drain without blocking water flow.
• Soil reconsolidation. The solution needed to fill voids beneath the road surface to prevent further settlement.

Traditionally, this repair would involve removing the roadway, excavating down to the storm drain, and replacing the system entirely. While effective, that approach can take weeks or months, cost significantly more, and still risk seam misalignment in the future, restarting the erosion cycle.

Proposed Solution

Helicon selected AP Fill 700 designed for deep soil permeation and water resistance. The material flows into fine cracks and joints inside the storm drain, seals gaps to prevent further soil loss, and bonds with surrounding soils for long-term stability.

The approach stabilized the system from the inside out, avoiding excavation.

Procedures 

1. Placed injection points to cover the compromised zones
2. Injected AP Fill 700 and around the storm drain
3. Allowed the resin to flow upward into surrounding soil layers, sealing the drain structure while recompacting soils supporting the roadway
4. Pumped 237 gallons of polyurethane resin across the affected area
5. Filled voids and formed a monolithic, water-resistant barrier
6. Confirmed the stabilized subgrade could carry heavy fire apparatus and daily traffic

Results 

• Restored roadway safety without excavation
• Extended the lifespan of the storm drain and pavement
• Prevented further erosion and void formation
• Completed the work quickly, with no operational downtime for the fire station
• Left the station with a fully stabilized access route capable of supporting heavy use

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Valley National Bank, in the heart of downtown Tampa, planned a major building expansion. The design called for a new elevator shaft, a structural element connecting multiple floors and relied upon daily by employees and clients.

Before construction could move forward, it was essential to confirm the foundation soil beneath the shaft could handle the load and vibration over the long term. In Tampa Bay's urban and coastal zones, unpredictable sandy soils pose serious risks for structures without proper stabilization. Valley National Bank turned to Helicon, Florida's trusted name in foundation repair, soil stabilization, and polyurethane grouting.

Initial Assessment

Helicon's site evaluation identified two hurdles.

Tight access. The shaft sat inside an existing, older building downtown. Narrow entryways, low overhead clearance, and the confined urban setting meant traditional foundation repair equipment would not fit. Helicon's polyurethane injection equipment is engineered for low-footprint, tight-access work where heavy machinery is not an option.

Sandy, unstable soils. The subsurface was primarily loose, granular sand, prone to shifting under heavy loads. Left unaddressed, it could cause uneven settling of the shaft, leading to operational problems and possible structural damage. The solution had to strengthen the sand without adding excessive weight, distribute load uniformly beneath the shaft footprint, and install without major disruption.

Proposed Solution 

Helicon selected AP Soil 600, a one-part, low-viscosity polyurethane permeation grout engineered for sandy soil stabilization. Low viscosity allows deep penetration into loose soils. The material is light relative to its strength, binds soil particles to reduce settlement risk, and resists water infiltration in Florida's wet climate. AP Soil 600 is widely used where high load-bearing capacity is required, including elevator shafts, bridge abutments, and commercial foundations.

Procedures

1. Evaluated the site to confirm subsurface conditions beneath the planned shaft footprint
2. Designed a grid of 14 injection points beneath the footprint
3. Drilled each point to 5 to 6 feet, targeting the soil layers most at risk of movement
4. Injected AP Soil 600 through the grid, ensuring coverage without gaps
5. Permeated the sand, locking it into a dense, load-bearing mass
6. Confirmed uniform support across the foundation before vertical construction began

Results 

• Delivered a stable base for both the static weight of the shaft and the dynamic forces of daily elevator operation
• Eliminated voids and weak points, increasing soil density and shear strength
• Installed quickly and cleanly with minimal disruption
• Kept construction on schedule
• Treated the soil before vertical construction, heading off future settlement and repairs

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For DOT maintenance teams, municipalities, public works departments, bridge maintenance engineers, and the contractors who perform concrete lifting, void filling, and soil stabilization work — what an unstable approach slab really costs, and why the bump is rarely the actual problem.

A bridge approach slab does not fail all at once. It shows up as a bump, then a dip, then a crack along the joint where the slab meets the deck. Crews patch it, grind it smooth, and move on. A few months later, the same spot is back on the list.

That cycle is why this problem is easy to underestimate. Each patch looks cheap on its own. It's the repeated mobilizations, the lane closures, and the eventual heavier repair that add up. Most of that cost has nothing to do with the asphalt on top. It's driven by what's happening in the soil underneath.

The Real Cost Driver Isn't the Patch

A single patch is inexpensive. What's expensive is the pattern: mobilizing a crew, setting traffic control, closing a lane, and grinding or filling the same joint — repeatedly, at the same location, because the cause was never addressed. Traffic control and mobilization alone often cost more than the patch material itself, and that overhead repeats with every visit.

Left long enough, the condition can progress from the slab into the structure itself. At that point, repair moves into abutment or wing wall territory, where structural work runs $500–$1,200 per square foot.

Actual costs vary by region, traffic control requirements, agency specifications, slab condition, drainage, soil conditions, access, and severity.

This gradual progression is the point: money spent patching the same location, over and over, without resolving the underlying condition — until it's no longer just a slab problem.

The Bump Is the Symptom. The Void Is the Problem.

An approach slab bridges two systems that behave very differently. The bridge itself sits on a foundation — an abutment, piles, drilled shafts, footings bearing on stable material. The approach slab sits on compacted fill and native soil. Those two systems settle at different rates, and that difference is where the trouble starts.

Common causes include:

• Fill settlement — backfill behind the abutment consolidates over time, especially if it wasn't compacted to spec.
• Erosion and soil loss — water finds a path under the slab or through a failed joint and carries fines out, leaving a void.
• Failed drainage — deck drains or approach drainage that no longer function concentrate water exactly where it does the most damage.
• Voids beneath the slab — once soil is lost, the slab spans open space instead of bearing on support, and traffic loading accelerates the cracking.

None of this is visible from the driving surface. What's visible is the bump — the downstream symptom of a support problem that started below grade.

Why Repeated Patching Doesn't Fix It

Asphalt patching and grinding improve ride quality fast, which is why they're usually the first response. But if there's a void or ongoing erosion beneath the slab, the patch sits on the same unsupported base that caused the original settlement. Traffic keeps flexing the slab over the void, the patch cracks again, and the crew returns on a schedule that tends to compress rather than stretch out.

Where Polyurethane Injection Fits

When the cause is loss of support — a void, settled fill, or eroded soil — polyurethane injection addresses that condition directly, without full slab removal. Small-diameter ports are drilled through the slab or pavement, and high-density polyurethane resin is pumped beneath it. The material expands to fill the void, densify loose soil, and in appropriate cases lift the slab enough to close the joint differential.

If a soil boring or dynamic cone penetrometer (DCP) test indicates weaker soils at greater depth, those layers can be targeted first with polyurethane injected several feet into the ground using Alchatek's Deep Lock® process — addressing the soil density issue driving the settlement before the slab itself is lifted.

This isn't a fit for every situation. It addresses void and soil support — not a structurally deficient slab, a failed expansion joint, or drainage that's actively delivering water to the site. Site conditions, soil type, drainage, and the extent of the void all factor into whether injection is appropriate.

Why Contractors and Agencies Work With Alchatek

Alchatek manufactures high-strength polyurethane systems for void filling, soil stabilization, and concrete lifting on roadway, bridge, and transportation infrastructure. For contractors working under DOT or municipal specifications, that means products engineered for wet conditions, rapid cure, and traffic-ready turnaround, backed by technical support from a team familiar with public infrastructure estimating and application questions.

The right approach depends on the cause of the settlement, the soil conditions, and the condition of the slab — not a one-size-fits-all fix.

Related Reading

• 5 Warning Signs a Structure May Need Slab Lifting or Stabilization
• A Trusted Polyurethane Soil Stabilization Resource for Engineers
• AP Fill 700 – Polyurethane for Pipe Repair

Talk to a Specialist

If an approach slab on your system is showing repeated settlement, the first step is understanding what's happening beneath it. Call an Alchatek specialist at (404) 618-0438, or find a trained contractor near you.

The structural repair range in this article is confirmed via Alchatek's Cost Reference Library. Actual costs vary by site conditions, region, traffic control requirements, agency requirements, slab condition, drainage, soil conditions, access, and severity of settlement.

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An interior elevator pit needed for ADA retrofit in a multi‑level building, inside an old stairwell beside a load‑bearing wall on sandy soils. Conventional shoring wasn’t feasible indoors with tight footprint and headroom limits.​ Stable Soils of Florida was called in to assess and remedy the situation.

Initial Assessment

• Sandy, below‑water‑table soils at a planned 7 ft pit depth.​

• Footing and slab at risk of undermining if excavated untreated.​

• No practical option for sheet piling, slurry wall, or trench box.​

Proposed Solution

Engineers designed a perimeter grout “box” using AP Soil 600, a low‑viscosity, single‑component permeation resin that bonds wet sands into a rock‑like, load‑bearing mass.

Procedures

1. Lay out pit and grout‑box perimeter around the planned excavation.​

2. Drill and set probes to depths below the final pit grade.​

3. Inject AP Soil 600 while slowly extracting probes to form overlapping treated columns.​

4. Allow cure, then excavate the pit inside the treated zone.​

5. Grind exposed treated face flat and use it as the outer form for the concrete pit.​

Results

Stable excavation adjacent to the load‑bearing wall with no observed soil loss.​
Interior elevator pit completed without conventional shoring or large equipment.​
Enabled ADA‑compliant vertical access using permeation‑stabilized in‑place soils.

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In Cape Canaveral, Florida, a heavily loaded slap stand structure was planned for construction along a transfer aisle in the Vehicle Assembly Building (VAB). This slap stand would be critical in servicing the proposed Space Launch System vehicle (SLS). However, the project faced a significant challenge when it was discovered that the near-surface subsoils consisted of loose fill materials susceptible to further densification and volume loss due to vibrations and water infiltration. With the slap stand tentatively designed to bear directly upon the ground-level floor slab of the VAB, the degree of subsoil support beneath the floor slab section became a critical concern.

Powerful Polymers

To address this issue, the geotechnical engineer of record recommended a ground improvement solution using permeation grout. Helicon, a leading soil stabilization contractor, worked alongside the geotechnical design team to develop a permeation grout program that would meet the building code load criteria. AP Soil 600, a high-strength, hydro-insensitive structural polyurethane foam, was selected as the ideal product for this project due to its exceptional ability to support heavy structures.

Painless Procedure

Helicon’s technicians installed permeation grout injection pipes on a center-to-center spacing of approximately 2 feet across each of the slap stand areas. The injection points were driven to a depth of at least 5 feet below the floor slab grade. Grout was injected at a relatively low pressure (less than 50 psi), and grout needles were slowly withdrawn during pumping to ensure a uniform distribution of grout to about 3 feet below the bottom of the slab level. The amount of grout used was carefully controlled, with less than 15 gallons per foot per injection point.

Rapid Result

The permeation grout project was a resounding success, effectively improving the load-bearing capacity of the existing soils at the site. The precise application of AP Soil 600 ensured that the slap stand structure would have a stable and reliable foundation, allowing for the safe and efficient servicing of the Space Launch System vehicle. Thanks to Helicon’s expertise and the power AP Soil 600, this piece of critical infrastructure in Cape Canaveral was reinforced and readied for countless future space exploration missions.

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Developers working on a new CVS Pharmacy in Orlando, Florida, encountered critical soil stability issues during the construction process. The project managers faced a significant challenge when geotechnical testing revealed unsuitable soil conditions between 5 and 10 feet below the surface, posing a threat to the structural integrity of the planned parking lot. This issue was discovered after site preparation had already begun, adding urgency to finding an effective solution that would allow construction to proceed on schedule.

Initial Assessment

A geotechnical analysis revealed that although the upper soil layers had been replaced, a layer of muck remained at depth, posing significant risks of settlement and potential structural failure in the parking lot. The site required comprehensive soil stabilization to proceed with construction. Traditional methods of excavation and replacement were deemed too time-consuming and costly, necessitating an alternative approach.

Proposed Solution

A comprehensive soil stabilization plan utilizing AP Lift 475, a two-component polyurethane foam, was proposed. This solution was chosen for its ability to:

• Consolidate soil throughout the parking lot area.
• Provide a stable foundation for the structure.
• Avoid extensive excavation and soil replacement.

AP Lift 475 was selected for its high strength and excellent expansion properties, which would allow it to effectively fill voids and stabilize the muck layer without adding significant weight to the unstable soil.

Procedures

1. Establish a 5-foot grid pattern across the entire parking lot area.
2. At each grid point, inject 25 pounds of AP Lift 475 at a depth of 10 feet.
3. Inject an additional 25 pounds at a depth of 5 feet at each point.
4. Monitor soil consolidation and adjust injection amounts as needed.
5. Perform post-injection testing to confirm soil stability.

Results

The polyurethane injection solution proved highly effective, successfully stabilizing the soil without the need for extensive excavation. This approach allowed the construction schedule to be maintained, avoiding costly delays that would have been incurred with traditional soil replacement methods. Post-injection testing confirmed that the treated area passed all required stability tests, demonstrating the effectiveness of polyurethane injection for large-scale soil stabilization projects in commercial construction.

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A public park in New York had critical erosion issues at its waterfront staircase and adjacent beach, which were built over a landfill. Over the years, natural erosion pulled back sand, exposing uneven foundation areas and creating safety hazards for visitors. The partially buried concrete staircase exhibited significant subsidence and shifting soil, posing a threat to structural collapse. The New York City Parks Department required a rapid solution to stabilize the site before further degradation occurred.

Initial Assessment

The staircase and surrounding sand exhibited signs of differential settlement, likely due to uneven soil compaction and erosion. Technicians identified voids beneath the stairs and along the beachfront, with sand migration exacerbating instability. Traditional excavation or pier-and-casing methods were impractical due to limited access and the need to avoid displacing adjacent structures.

Proposed Solution

The team selected AP Fill 720 (a single-component polyurethane) for soil compaction/stabilization and AP 430 (a two-component foam) for structural void filling. AP Fill 720 addressed loose sand through permeation and consolidation, while AP Lift 430 filled critical voids beneath the staircase, providing lift and support.

Procedures

1. Stabilization Pattern: Injected AP Fill 720 every 4 feet at 6–8 feet depth to bond sand particles and prevent further migration.
2. Structural Foam Injection: Applied AP Lift 430 directly beneath the staircase’s granite slabs through strategic ports, filling void spaces with approximately 1 gallon per linear foot.
3. Final Treatment: Reserved excess AP Fill 720 to seal surface gaps around the staircase, preventing sand washout.

Results

The dual-material injection rapidly stabilized the waterfront staircase, eliminating soil migration and structural risk without closing the park. Compared to traditional heavy reconstruction, the approach cut costs by an estimated 97% and completed the work in under two weeks with minimal marine or community disruption. Post-repair inspections confirmed lasting results with no recurrence of erosion.

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Initial Assessment

The management team at a corn syrup plant faced significant challenges with sinking concrete slabs supporting critical infrastructure, including water tanks and raw material tanks. The uneven slabs posed risks of tank instability and potential structural failure. A geotech contractor was engaged to perform void filling and stabilize the affected areas, ensuring a solid foundation for plant operations.

Proposed Solution

The technical team recommended using AP Lift 475, a two-component polyurethane foam that is ideal for void filling and slab stabilization. This material was selected for its high compressive strength, controlled expansion, and ability to effectively fill voids while providing robust support for heavy loads. The approach ensured minimal disruption, as it required no extensive excavation.

Procedures

1. Established a grid pattern to guide the placement of injection points in the affected areas beneath and around the water and raw material tanks.
2. Drilled holes through the concrete slabs at predetermined injection points to access the voids beneath.
3. Injected AP Lift 475 polyurethane foam into the drilled holes to fill voids and stabilize the soil beneath the slabs, ensuring comprehensive void coverage.
4. Patched drilled holes to restore the surface integrity of the concrete slabs.

Results

The void-filling project at the corn syrup plant was a success. The application of AP Lift 475 effectively filled all identified voids, stabilizing the concrete slabs and restoring a solid foundation. The stabilized areas now securely support the water and raw material tanks, eliminating concerns about sinking or tipping. The facility can resume full operations with confidence in the structural integrity of the tank foundations.

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