Alchatek Blog

The US Army Corps of Engineers (USACE) required a solution to fill the annular spaces between eight 84-inch ductile iron pipes and the concrete bulkhead at a new pump station along the Mississippi River in Port Sulphur, Louisiana. Traditional methods, such as pouring non-expanding resin, were cost-prohibitive (approximately $50,000 per void) and lacked the necessary performance characteristics. The voids posed a risk of instability and water infiltration, demanding a material that combined strength, adhesion, and environmental safety.

Initial Assessment

Inspections revealed significant annular gaps around the pipes, necessitating a material that can bond to both ductile iron and concrete while forming a waterproof seal. The USACE prioritized a solution that avoided excavation, minimized downtime, and provided long-term durability. Based on the scale of the pipes and typical annular space requirements, the voids were estimated to range from 6 to 12 inches in width around each pipe, although exact dimensions would depend on site-specific conditions.

Proposed Solution

Alchatek’s AP Lift 430, a high-density, two-component polyurethane foam, was selected for its compressive strength of 7,200 psf, ensuring structural support while adhering tightly to both ductile iron and concrete. Its hydrophobic nature prevents water infiltration,  and its expansion capability allows for complete void filling without precise volume calculations. AP Lift 430 provided a balanced solution for strength, durability, and cost efficiency.

Procedures

1. Material Application: AP Lift 430 was free-sprayed into the annular spaces using a Graco Fusion spray foam gun, ensuring deep penetration and adhesion to both the ductile iron pipes and the concrete bulkhead.
2. Curing and Expansion: The foam expanded to fill the voids, creating a seamless and waterproof barrier.
3. Surface Finishing: Excess foam was ground flush with the concrete surface to allow secure installation of flanges and gaskets.

Results

The project was completed in two days, with no disruptions to ongoing site operations. AP Lift 430 formed a durable, watertight seal, meeting all USACE requirements for strength and longevity. Total material costs were approximately $30,000, representing a 90% cost savings compared to other resin-based alternatives. The USACE supervisor conducted daily inspections and praised the efficiency and quality of the repair.

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Alchatek proudly supports the Wounded Warrior Project, a nonprofit founded in 2003 to empower post-9/11 veterans with physical or mental injuries, along with their families and caregivers. Its mission is to create the most successful, well-adjusted generation of wounded service members in U.S. history.

Wounded Warrior Project - Origins

The Wounded Warrior Project began in Roanoke, Virginia, when Marine Corps veteran John Melia, injured in a 1992 helicopter crash, saw the needs of returning Iraq and Afghanistan veterans. He and his friends raised $5,000 to deliver backpacks with essential supplies to wounded soldiers at Walter Reed Army Medical Center. From this small act, the Wounded Warrior Project grew into a national organization offering comprehensive support.

Wounded Warrior Project - Services

• Mental Health Support: Workshops, retreats, and counseling to build resilience and community, helping veterans feel less isolated.
• Physical Wellness Initiatives: Adaptive sports, cycling events, and wellness challenges to promote rehabilitation and camaraderie.
• Financial Guidance: Career advice, job placement, and benefits counseling to ensure economic independence.
• Support for Severely Injured Veterans: Ongoing assistance for injured veterans and caregivers, including a resource hub for personalized service connections.

Through partnerships and advocacy, the Wounded Warrior Project drives veteran-friendly policies and collaborates with organizations to expand care. Veterans credit it with transformative opportunities, from adventures to career growth.

Alchatek is deeply honored to have supported this vital mission for over 10 years. In recognition of our commitment, we were humbled to receive a challenge coin from the Wounded Warrior Project, a symbol of our shared dedication to those who’ve served our nation.

Join us in making a difference - click the button below to donate today.

Alchatek is pleased to announce the promotion of Andrew D. Powell to the role of Vice President of Sales. Previously, Business Development Manager, we congratulate Andy on his new executive position in recognition of his extensive experience and contributions to the company's growth since joining us.

With extensive experience in manufacturing, application, equipment, estimating, field service, and training for the entire product line, Andy has worked with many clients, including several state departments of transportation and high-profile institutions such as the Army Corps of Engineers, Duke Energy, and Florida Power and Light. Andy attended Georgia Tech and Auburn University and is well-equipped to succeed in his new position as Vice President of Sales.

Alchatek Chief Executive Officer Stephen Barton comments on the promotion, "Andy has been a leader in our organization for over 12 years, and we are looking forward to his continued leadership in his role as Vice President of Sales. Andy will be the primary driver of our bold new strategy as we expand our product and service offerings in the coming years."

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Initial Assessment

The team at PURLevel was contacted regarding significant floor settlement issues at Outpost Harley-Davidson in Pueblo, Colorado, where a water pipe rupture had resulted in concrete movement and void spaces beneath the floor. The affected areas showed uneven surfaces with depressions ranging from 0.25 to 3 inches, creating hazards for both foot and equipment traffic.

Proposed Solution

AP Lift 430 polyurethane foam was selected for this project due to its excellent void-filling and lifting capabilities. With its 22x expansion capability and 7,200 psf compressive strength, this material is ideal for commercial floors supporting heavy equipment like that found in a motorcycle dealership.

Procedures

1. Site Preparation

   • The affected area was thoroughly inspected to determine the full extent of damage.
   • A 5'x5' grid pattern was marked across the entire interior floor area.

2. Grid Injection

   • Strategically placed injection points were established following the grid pattern.
   • Holes were drilled through the concrete slab at each injection point.
   • Polyurethane foam was systematically injected to fill voids beneath the slab.

3. Lift and Stabilization

   • After initial void filling, additional injections were performed to lift the sunken areas gradually.
   • An incremental lifting approach was used to prevent concrete cracking.
   • Areas requiring significant lift (up to 3 inches) received multiple injection passes.
   • Levels were continuously monitored to ensure even lifting across the floor surface.

Results

The project successfully stabilized the Outpost Harley-Davidson floor and restored it to its proper level. The comprehensive void-filling addressed the underlying instability caused by the water pipe rupture, providing a solid foundation for the concrete slab. Success was evident in the restored functionality of the dealership floor and the elimination of safety hazards posed by the uneven surface.

Want more information on leveling concrete slabs?

Concave ports, for use with PX-7 Slab Lifting Guns, offer enhanced performance for concrete lifting with their unique dimple top and black sealing sleeve for a secure fit. Their durable design ensures reliability under tough conditions, while the sleeve's ability to seal directly to concrete minimizes leaks and boosts efficiency, reducing the need for frequent port replacement due to leakage. 

Features

• Dimple top.
• Includes black sealing sleeve.

Benefits

• Durable design ensures enhanced reliability.
• Sleeve seals to concrete.

Requires a standard gun clamp.
Available in bags of 100.

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Attention Geotech Professionals!

Alchatek is exhibiting at the DFI S3: Slopes, Support and Stabilization Conference.

Where: Madison Marriott West in Madison, Wisconsin

When: August 5–7, 2025

Click Here for Registration Info

Visit us at Booth 302 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 302, 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.

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Buchanan Dam, located on the Colorado River in Texas, is a critical infrastructure built in 1937 to form Lake Buchanan. The dam is one of the longest multiple-arch dams in the world and serves as a vital resource for hydropower generation and flood control. Over time, the dam developed high-pressure water leaks in its concrete arches, particularly in Arch 47. These leaks were exacerbated by seasonal temperature fluctuations, which caused thermal expansion and contraction, leading to recurring cracks and water infiltration. Restek, Inc., a contractor specializing in structural repairs, collaborated with Alchatek to implement a polyurethane grouting solution to address these issues.

Initial Assessment

An inspection of the dam revealed severe water infiltration concentrated in Arches 45-47. Arch 47 presented the most aggressive leaks, with water flowing under high pressure. Previous injection efforts had only provided temporary relief due to insufficient grout penetration and equipment limitations. The concrete structure’s thickness and seasonal movement posed additional challenges for effective leak sealing.

Proposed Solution

Alchatek recommended using a combination of advanced polyurethane products tailored to the dam’s specific conditions. Spetec PUR HighFoamer was selected for high-pressure leaks due to its rapid reaction time and expansive properties. Spetec PUR H100 and Spetec PUR F1000 were chosen for lower-flow areas requiring flexibility to accommodate joint movement. Higher-capacity airless pumps, such as the Titan 640 and Titan 8900, were utilized to ensure effective grout delivery.

Procedures

1. Preparation:

• To reach the midpoints of the concrete structure, deeper injection points were drilled using 24-inch and 36-inch masonry drill bits.
• Oakum rope saturated with grout was packed into joints to slow water flow during the injection.

2. Injection Process:

• Spetec PUR HighFoamer mixed with Alchatek Gen Cat was injected into high-flow leak areas using upgraded pumps capable of handling high pressure.
• Flexible grout mixtures (Spetec PUR H100/PUR F1000) were injected around rigid plugs to reinforce sealed areas and accommodate seasonal joint movement.

3. Post-Sealing Monitoring:

• The team monitored material expansion within cracks and adjusted injection pressure as necessary to ensure complete sealing.

Results

The grouting crew successfully sealed leaks throughout Arches 45-47. High-flow leaks in Arch 47 were effectively stopped using Spetec PUR HighFoamer, while lower-flow leaks were addressed with flexible polyurethane grout mixtures. Equipment upgrades allowed deeper injections, overcoming previous limitations and ensuring long-term durability against thermal stresses. Subsequent inspections confirmed substantial reductions in water infiltration, with no major leak recurrence reported.

Conclusion

The Buchanan Dam leak-sealing project demonstrated the importance of combining advanced materials with appropriate equipment upgrades to address complex infrastructure challenges. Restek, Inc.'s collaboration with Alchatek resulted in a sustainable repair strategy that restored the dam’s structural integrity while accommodating environmental factors such as temperature fluctuations. This case underscores polyurethane grouting’s effectiveness as a solution for high-pressure leak repair in large-scale concrete structures.

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This post is part of the Alchatek Contractor Lens series, featuring views, news & case studies written by our customers. This article was written by Jay Silver and originally posted on the Helicon blog.

When Excavation Gets Tight, Think Beyond Sheet Piles

Excavating near an existing structure — like a home, commercial building, or utility line — often requires soil support to avoid collapse or damage. For decades, the go-to solution has been sheet piling: driving steel sheets into the ground to create a temporary shoring wall.

But sheet piles come with serious downsides:

• High cost
• Vibration risks to nearby structures
• Heavy equipment needs
• Limited accessibility in tight areas

Today, there’s a smarter, faster, and more cost-effective alternative for excavation support: polyurethane injection permeation grouting.

What Is Polyurethane Grout Injection for Excavation Assist?

Helicon uses a permeation grout called AP Soil 600, a low-viscosity polyurethane resin, to stabilize soil and build a temporary underground wall. This non-expanding material seeps into fine-grained soils (like sand), then hardens into a concrete-like mass — turning unstable ground into a solid excavation shoring wall.

This “grout curtain” supports the soil adjacent to your dig site, providing excavation assist without the need for steel sheets or heavy machinery.

Common Use Cases for Polyurethane Shoring Walls

Excavations next to homes or commercial buildings

Tight-access job sites where pile driving equipment won’t fit

Urban infill projects with vibration-sensitive neighbors

Value-engineered alternatives to high-cost sheet pile installation

Projects with depth requirements up to ~15 feet

Sheet Piles vs. Polyurethane Injection

How It Works: The Grout Curtain Process

1. Plan and Mark
The contractor provides excavation depth and layout. Helicon’s team maps out injection lines using stakes or string to ensure precision.

2. Drill Injection Holes
Using compact equipment, injection rods are installed at a slight 3–5° angle away from the excavation. Rods are spaced 18″ apart, and for depths >8 feet, a second staggered row is added 18″ behind the first.

3. Inject AP Soil 600 Grout
Each rod is used to inject grout in 1-foot intervals from bottom to top:

• Start 2 feet below planned excavation depth
• Inject 1 gallon per vertical foot
• Grout permeates and hardens in ~2 minutes per foot
• Stops 1 foot below surface to avoid breakout

The non-expanding grout permeates the soil, turning it into a rigid, cohesive wall capable of holding back earth during excavation.

4. Excavate Safely
Once cured (typically within 24 hours), excavation can begin — but mechanical equipment must stay 2+ feet away from the grout wall. Final trim is done by hand or hydro-vac.

Soil Types That Work Best

AP Soil 600 is designed for permeation, not expansion. It’s ideal for:

✅ Sand
✅ Fine silts
✅ Granular soil types

⚠️ Less effective in:

• High plasticity clay (which resists permeation and may not need shoring)
• Organic material or very dense clay (which can fracture or lens)

That’s why soil boring reports or geotechnical testing are important for project design.

Depth Recommendations

Helicon’s polyurethane grout walls are most effective up to 15 feet. Beyond that, multiple injection rows become inefficient, and other structural shoring may be needed.

Cost Savings & ROI

Switching from sheet piles to Helicon’s polyurethane grout method can save:

• Tens of thousands on residential jobs
• Up to six figures on larger commercial projects

Savings come from:

• No need for steel or removal
• Smaller crews and equipment
• Shorter install times
• No costly vibration damage

Combine with Underpinning When Needed

When adjacent structures need more than soil support, Helicon can pair permeation grouting with:

• Push piers (steel-driven deep supports)
• Drilled piers (poured concrete or steel)

This hybrid approach is ideal for:

• Older buildings
• Structures with active settlement
• High-load foundations near deep excavation

Real-World Examples

On a commercial project, the contractor and engineer originally planned to use traditional sheet piles for shoring to support the foundation of a commercial building. Helicon collaborated with the engineer to develop a value-engineered alternative: a polyurethane grout curtain combined with steel push piers installed under the building’s foundation. The shoring wall and underpins were completed within five days, excavation proceeded safely, and the client saved over $300,000 compared to the original sheet pile proposal.

On a recent project with access constraints, Helicon installed a polyurethane grout curtain within 2 feet of a residential foundation. Traditional sheet piles weren’t an option due to equipment access and budget. The wall was in place within two days, excavation followed safely, and the client saved over $70,000 compared to a sheet pile proposal.

Safety Guidelines

• Injection starts 2’ below excavation depth
• Do not excavate within 24” of cured grout with equipment
• Always hand dig near the grout wall
• Excavation limit line should be marked 33” back from rods (accounting for rod angle)

Why Engineers and Contractors Choose Helicon

• Florida-based foundation experts
• Proven track record in geotechnical solutions
• Fast mobilization and project turnaround
• Seamless integration with GCs, engineers, and owners
• Full service: injection + underpinning + stabilization

Optimize Your Excavation Support Plan

If you’re a contractor, builder, or geotechnical engineer working on an excavation project in tight quarters, don’t default to sheet piles. Helicon’s polyurethane injection method is often:

• Faster
• Cheaper
• Cleaner
• More flexible

Helicon specializes in value-engineering shoring solutions that reduce project costs and risks while maintaining structural safety and soil integrity.

Let’s Put Your Excavation Project on Solid Ground

Have a project where you’re excavating near a structure? Let’s collaborate. Helicon offers:

• Free project consultations
• Soil review and injection layout planning
• Rapid response teams for tight timelines

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Gerace Construction undertook a gate replacement project at the Tom Miller Dam in Austin, Texas. While working on Large Gate #6, and after installing a needle beam cofferdam system to lower the water level, a continuous wet spot was discovered under the metal gate sill. This indicated a crack in the concrete extending under the sill plate. Sealing the leak was necessary to prepare and coat the steel sill plate, which was crucial for the overall gate replacement.

Initial Assessment

The primary challenge was water seeping through a crack, less than one linear foot in length, located in the concrete beneath the steel gate sill. The cofferdam system had created approximately 18 feet of head pressure upstream, with the water level pumped down about two feet below the sill. As per the project specifications, a dry surface was required to apply coatings to the steel sill plate.

Proposed Solution

Alchatek recommended Spetec PUR H100 to seal the crack. This hydrophobic polyurethane resin was chosen for its ability to rapidly seal cracks with reasonable water flow and minimal anticipated movement. The solution involved injecting the resin into the crack to create a watertight seal, allowing the steel surface to dry for coating application. Alchatek also provided an on-site representative during the injection process, as required by the project specifications.

Procedures

1. Preparation:

• The contractor established the cofferdam system and lowered the water level to expose the leaking area.
• Injection ports were installed along the crack at 12-inch centers on alternating sides.

2. Injection Process:

• Spetec PUR H100 mixed with Alchatek Gen Cat was injected into the crack using positive displacement equipment capable of maintaining a minimum pressure of 250 psi.
• Injection began at the lowest port and continued sequentially upward until grout filled the crack and seepage ceased.
• Inline pressure was monitored throughout to ensure it did not drop below 190 psi during injection.

3. Post-Injection:

• The injected resin was allowed to cure fully, forming a watertight seal.
• Excess surface seal material was removed, and the repaired area was inspected to confirm no further water intrusion.
• The injection ports were removed, and holes were patched flush with hydraulic cement as per project guidelines.

Results

The application of Spetec PUR H100 successfully sealed the leak under the steel gate sill, allowing Gerace Construction to proceed with surface preparation and coating application. The fast-reacting properties of Spetec PUR H100 minimized delays while ensuring long-term durability against water infiltration. The Lower Colorado River Authority (LCRA) engineering staff approved of the product, and the Alchatek representative provided the required on-site supervision ensured compliance with all quality assurance measures, resulting in a successful repair that restored functionality and structural integrity to Gate #6 at Tom Miller Dam.

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The PX-7 incorporates a valving rod to mechanically purge the mixed material from the mixing module at the end of each shot; eliminates the need for solvent flushing or air purge. It comes standard with a precision machined coupling block made from high strength steel. Manufactured by Polyurethane Machinery Corporation.

Key Features

• Economically Priced
• Mechanically Self Cleaning
• Solvent Free
• Airless Atomization
• Internal Impingement
• Machined Coupling Block
• Precision Ground, Single Piece Valving Rod
• Rebuildable Manual Valves
• Stainless Steel Hardened Gun Block
• CE Certified

Want more information on the PX-7 Mechanical Purge Gun?