Alchatek Blog

A tunnel structure in the Mobile, Alabama area had persistent water infiltration at the interface between concrete and metal components. The leak was traced to a tight crack at the joint, allowing water to migrate into the tunnel and cause visible staining, as well as potential long-term deterioration. The client sought a solution that would seal the leak without requiring major demolition or extended tunnel closure.

Initial Assessment

Visual inspection and on-site review identified the leak path at the interface between the concrete and metal. The crack width was measured between 0.2 and 0.3 mm, indicating that traditional cementitious grouts or surface sealants would not be effective. The challenge was to deliver a material that could penetrate deep into the joint and expand to form a watertight seal, even in confined spaces and around embedded metal.

Proposed Solution

Alchatek recommended Spetec PUR F400, a low-viscosity, hydrophobic polyurethane grout. Its ability to penetrate narrow cracks and react with water creates a durable, flexible seal. The product’s flow characteristics made it ideal for tight joints, and its expansive properties ensured comprehensive coverage within the voids and cracks. The injection plan called for drilling at the locations marked on the provided site photos, angling back toward the metal at approximately 18 inches deep to intersect the leak path.

Procedures

1. Identified injection points along the crack, using red-dot markings on the structure as a guide.
2. Drilled holes at 45° angle 12-inches apart, reaching approximately 18 inches deep to intersect the metal interface.
3. Injected Spetec PUR F400 polyurethane grout through the drilled ports, using a pump setup suitable for low-viscosity materials.
4. Monitored for material refusal and evidence of grout migration to ensure the joint was fully saturated and sealed.
5. Continued injection until the crack would not accept additional material, confirming a complete watertight barrier.

Results

The injection process successfully sealed the tunnel leak at the concrete-to-metal interface. The approach allowed for precise targeting of the leak path, with minimal disturbance to the tunnel structure and no need for extended closure or demolition. The client was able to resolve the water infiltration efficiently, reducing the risk of future deterioration and avoiding the significantly higher costs and downtime associated with traditional excavation or membrane replacement. This project demonstrates the effectiveness of modern polyurethane injection in addressing challenging below-grade leak scenarios, particularly where access is limited and the leak path is confined.

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In the realm of leak seal solutions, selecting the right equipment is crucial for the effective application of grouts. The SealMaster gun, developed by Alchatek, is designed specifically for crack injection and curtain grouting tasks. This tool facilitates controlled delivery of materials into cracks and voids, ensuring thorough penetration and sealing in concrete structures. Ideal for professionals in advanced leak seal operations, the SealMaster gun combines functionality with user-friendly features to support an efficient workflow on-site.

Features

• Built-in pressure gauge.
• Extended whip hose.
• Simple design.

Benefits

• Monitor back pressure.
• Low maintenance.
• Easy port connection and disconnection.

The SealMaster adjustable flow gun stands out as a reliable choice for contractors focused on leak seal applications, offering simplicity and precision that minimize downtime and enhance project outcomes.

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After the removal of a wooden deck, dangerous voids under the brick pavers were revealed in a luxury apartment pool deck, threatening its integrity and safety. The property owner contacted Helicon, a trusted foundation repair company.

Initial Assessment

Subsurface investigation confirmed extensive voiding with no practical access for excavation during occupancy. Demolition/replacement would take weeks, cost tens of thousands, and the pool would need to be closed during peak season.

Proposed Solution

The contractor selected AP Lift 440 for its hydro‑insensitivity, ~15‑minute cure, and ~80 psi compressive strength. This material was ideal for increasing the soil's bearing capacity and restoring the pool to its correct state.

Procedures

1. Map the void locations using ground-penetrating radar and probing.
2. Establish an injection grid targeting the largest voids first.
3. Drill strategic injection ports through pavers to void spaces.
4. Inject AP Lift 440 to refusal using calibrated pressure monitoring.
5. Allow 15-minute cure
6. Seal injection ports and restore surface aesthetics.

Results

• Structural integrity fully restored with 1,200 lbs of AP Lift 440, filling all voids.
• Zero operational downtime; pool deck remained accessible throughout repair.
• Approximately 70-90% cost savings compared to demolition/replacement alternatives.

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A Tennessee state correctional facility had a significant infrastructure failure when newly installed plumbing beneath a concrete slab malfunctioned. In an attempt to address the issue, the original contractor backfilled the entire plumbing system with concrete. When this approach proved unsuccessful, a second contractor was brought in to demolish the concrete and properly repair the plumbing systems. This process left a substantial void beneath the slab that required immediate filling to restore structural integrity and minimize facility downtime.

Initial Assessment

Following the plumbing repairs, engineers assessed a void measuring approximately 200 square feet in area and 4-5 feet in depth, totaling roughly 800-1,000 cubic feet of empty space beneath the concrete slab. The prison's security restrictions severely limited access to equipment, making traditional concrete replacement a challenging and time-consuming process. The facility required a solution that would minimize disruption to operations while providing structural support equivalent to the original concrete base.

Proposed Solution

Working with Alchatek, Mid-South Concrete Lifting recommended using  AP Fill 420, a two-component structural polyurethane foam, to fill the substantial void. This approach offered several critical advantages for the correctional facility environment. The material could be applied through a simple hose system, eliminating the need for heavy concrete trucks and mixing equipment that would be difficult to maneuver through security checkpoints. The foam's rapid curing time would significantly reduce the project timeline, and its structural properties would provide adequate load-bearing capacity for the slab above.

Procedures

1. Security clearance and equipment inspection were completed to bring polyurethane application equipment into the facility.
2. The void was accessed through existing openings created during the concrete removal process.
3. AP Fill 420 was applied using a free-shooting technique.
4. Material application was monitored to ensure complete filling and proper expansion throughout the space.

Results

The void filling was completed in 3 hours versus an estimated week for concrete replacement. AP Fill 420 polyurethane foam successfully filled the entire void space and provided adequate structural support. Prison officials expressed satisfaction with the efficiency and minimal operational disruption, leading the contractor to look at another similar project at a different state facility.

The polyurethane approach delivered 65-75% cost savings compared to traditional concrete replacement when accounting for materials, equipment, labor, and reduced facility disruption. The accelerated timeline also eliminated the extended security coordination costs typically associated with longer construction projects.

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Alchatek has streamlined its two-component production system according to lean manufacturing guidelines. These investments will ensure timely delivery of the high-quality products our customers depend on for their geotechnical projects.

• Material Handling System Automation: Our improved system speeds up material production while keeping quality levels high, ensuring a consistent supply of finished products to meet growing customer demand.
• Streamlined Filling Process: By redesigning workflows to minimize non-value-added activities, we’ve simplified operations, reducing cycle time and boosting team productivity. This translates to faster delivery and greater reliability for customers.
• Real-Time Process Monitoring: Advanced sensors provide continuous feedback on bulk tank material levels, enabling just-in-time inventory management. This keeps our production agile, ensuring customers get the products they need without delays.

These lean-driven investments reflect Alchatek’s dedication to customer satisfaction. By focusing on value stream optimization, we’re better equipped to deliver reliable, high-quality solutions to support your geotechnical projects efficiently and effectively.

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Fifteen, two‑unit condominium buildings exhibited differential settlement and interior slab movement from loose organics and voiding, risking structural performance and livability. Continuous occupancy required a rapid, low‑disruption remediation strategy that delivered durable lift and stabilization. The job was completed by foundation repair specialists at Helicon.

Investigations confirmed loose to very loose near‑surface soils, voids at 3–8 ft below the surface, and active settlement beneath slabs and footings under service loads; full replacement was not viable due to resident displacement, extended schedules, and higher cost risk.

Proposed Solution

The experts at Helicon selected AP Lift 440 for its hydro‑insensitivity, rapid reaction, and ~80 psi compressive strength to permeate, densify, and lift with minimal downtime.

Procedures

1. Grid the interiors; mark piles, grout points, and quality control benchmarks.
2. Inject low‑mobility compaction grout to seal limestone and pre‑densify.
3. Install underpinning to ~36 ft, using predrill/sleeves to bypass clays.
4. Inject AP Lift 440 at 8/5/3 ft below land surface to lift slabs and encapsulate organics.
5. Monitor elevations/pressures; proof‑load and video‑verify.

Results

• Restored slab elevations and footing support with no resident displacement.
• Completion in days to weeks vs months for replacement.
• Approximately 80-90% cost savings versus full demolition/rebuild approaches.
• Durable, closed‑cell, water‑resistant stabilization for long‑term performance.

Want more information on polyurethane slab lifting?

In the fast-paced world of geotechnical contracting, having a team member who truly understands the grind of the field can make all the difference. That's why we're thrilled to introduce Antwon Butts, our newest Tech Support Technician on the Technical Services team. With a career built on the front lines, Antwon steps into this role ready to bridge the gap between product innovation and real-world application, helping contractors like you tackle everything from soil stabilization to complex grouting challenges with confidence.

Antwon's journey in the industry is a testament to his dedication and versatility. He most recently served as Production Manager here at Alchatek, where he honed his skills in manufacturing and quality control for polyurethane-based solutions—ensuring every batch meets the high standards demanded by demanding jobsites. Prior to that, as Lead Technician at Ground Consolidation Services, he led on-site operations for soil consolidation and injection projects, managing teams through high-stakes scenarios that required quick thinking and precise execution. Over more than a decade, these roles have equipped him with a deep well of practical knowledge, from equipment troubleshooting to optimizing workflows under pressure.

What sets Antwon apart is his ability to translate that hard-earned experience into actionable support for you. Whether you're dealing with void filling, concrete lifting, or emergency repairs, his expertise in a broad spectrum of tools, products, and techniques means faster resolutions and fewer headaches. As any seasoned contractor will tell you, field proficiency isn't just valuable—it's irreplaceable. With Antwon on board, our Technical Services team is even better positioned to be your go-to partner, turning potential pitfalls into seamless successes.

Antwon can be reached via phone at 470-925-1303.

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A south Georgia roadway developed a sinkhole over a double 48-inch RCP storm line about 10 feet deep, threatening lane safety and mobility. Replacement costs were prohibitive and would require extended closure and excavation.

Initial Assessment

The pipe exhibited joint leakage and surrounding soil loss, creating voids under pavement and shoulder with settlement risk across the travel path. Traditional open-cut replacement would demand deep shoring, traffic detours, and high restoration costs, making trenchless stabilization preferable. SiteMix Pressure Grouting LLC was called in to do the work.

Proposed Solution

The contractor selected AP Lift 475 for hydrophobic chemistry, industrial strength, and rapid set to encapsulate pipe exteriors, seal soil paths, and rebuild bearing capacity with minimal downtime.

Procedures

1. Lay out three rows on 3-foot centers around both barrels.
2. Inject at 6 lb per vertical foot to refusal for soil reconsolidation.
3. Pull the injection tubing vertically while injecting to form grout columns.
4. Encapsulate/seal pipe perimeter and monitor lift response.
5. Verify surface support and closure readiness.

Results

• Completed in one day with 1,400 lbs placed; roadway lifted and voids eliminated.
• Zero excavation and minimal traffic disruption during work.
• Approximately 95% cost savings compared to pipe replacement.

Want more information on lifting slabs with polyurethane?

A fire station access roadway developed cracking from subsurface voids caused by storm drain seam gaps that washed out soil during heavy rain, threatening daily emergency operations and pavement integrity. Geotech specialists from Helicon were brought in to assess the situation.

Initial Assessment

CCTV and probing identified voids up to several inches beneath the asphalt and open joints along the drain, allowing soil migration. Excavation replacement was rejected due to weeks-long closure risk, higher cost, and potential future seam misalignment, making trenchless permeation grouting the viable path.

Proposed Solution

AP Fill 700 was chosen for hydrophobic, single‑component injection with very low viscosity, and adjustable cure, enabling soil permeation, joint sealing, and formation of a water‑tight bearing layer for traffic.

Procedures

1. Map defects and mark the injection grid along the pipe and pavement.
2. Drill ports; set packers to target joints and halo around pipe.
3. Inject AP Fill 700 to refusal, prioritizing seam sealing.
4. Permeate surrounding soils to fill voids and densify subgrade.
5. Monitor pressures/returns; adjust set times for water presence.
6. Verify with sounding/CCTV and traffic proof-load.

Results

• Restored structural support and sealed joints with zero operational downtime.
• Completion in days vs weeks.
• Approximately 95% cost savings compared to full excavation and pipe replacement.

Want more information on geotech products?

Attention Geotech Professionals!

Alchatek is exhibiting at the DFI 50 conference in Nashville.

Where: Gaylord Opryland Resort & Convention Center

When: October 20-23, 2025

Click Here for Registration Info

Visit us at Booth 227 to explore our advanced polymer solutions, including single and two-component polyurethanes for soil stabilization, groundwater control, and deep foundation support, addressing challenges like unstable slopes, soft ground, and deep excavation shoring for geotechnical projects.

Learn How Alchatek Helps You

At Booth 227, you can meet with our experts to learn how Alchatek empowers your geotechnical projects with cutting-edge technologies.

We support geotech professionals in three key ways:

• Innovative Polymer Solutions: Our advanced polyurethane grouts and foams provide robust solutions for curtain grouting, point grouting, and ground improvement, ensuring stability for slopes, excavations, and deep foundations.
• Expert Technical Support: We offer comprehensive training and ongoing assistance, leveraging our proven track record with industry leaders to optimize your project outcomes.
• Environmentally Safe Materials: Our NSF/ANSI/CAN 61-certified, chemically inert polymers ensure safety and compliance in sensitive environmental areas.

Want more information on Alchatek products?