Alchatek Blog

The Cave Buttes Dam, located in Phoenix, Arizona, required modifications that involved installing a 60-inch diameter steel conduit pipe beneath the dam through bedrock. During tunneling operations, a 15-foot-wide fault zone containing water and composed of clay was encountered. After the excavation and grouting of the annular space between the pipe and the rock with cementitious grout, leaks began to emerge from some of the welded grout packer plugs. SSC Underground was the contractor for this project, with engineering oversight provided by AECOM and the U.S. Army Corps of Engineers.

Initial Assessment

The primary issue was leaking grout plugs, which were 2-inch diameter, straight-threaded plugs welded into place after the initial grouting process. These plugs exhibited varying degrees of water seepage, with flow rates estimated at a few gallons per minute. The leaks were attributed to anticipated movement between the steel pipe and the surrounding rock due to temperature changes and vibrations. Based on these conditions, a flexible chemical grout was determined to be the best solution to seal the leaks while accommodating future movement.

Proposed Solution

Alchatek recommended injecting Spetec PUR F400, a flexible polyurethane grout, to seal the leaks. This grout was selected because of its ability to bond effectively while maintaining flexibility to withstand differential movement between the steel pipe and surrounding materials. The plan involved drilling into the existing grout plugs and injecting Spetec PUR F400 through packers to confine the grout and ensure a complete seal. The project utilized packers for controlled injection and a Titan Impact 440 pump to deliver the grout. Alchatek Gen Cat was used to manage the grout’s reaction time based on the specific site conditions.

Procedures

1. Preparation:

• The team drilled into the center of each leaking grout plug to create access points for injection.
• Packers were installed into these drilled holes to facilitate the controlled injection of the grout.

2. Injection Process:

• Spetec PUR F400 was injected through the packers using a Titan Impact 440 pump.
• Alchatek Gen Cat was added to the grout mixture to adjust reaction times as needed.
• The injection process was monitored to ensure proper confinement of the grout within the leaking areas.

3. Post-Repair Monitoring:

• After sealing each leaking port, inspections were conducted to confirm the cessation of water infiltration.
• New leaks that emerged from previously sealed or new locations were identified for subsequent treatment.

Results and Conclusion

The initial injection process sealed most of the identified leaking grout ports, effectively stopping water infiltration at those locations. However, water subsequently found new paths, resulting in additional leaks from previously sealed ports. The team used the same materials and procedures to address these additional leaks through follow-up injections. Ultimately, all leaks were successfully sealed, restoring the integrity of the steel pipe installation.

Want more information on polyurethane leak seal materials?

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Attention Engineers!

Alchatek is exhibiting at the International Conference on Transportation & Development and the International Airfield & Highway Pavements Conference, held at the Renaissance Phoenix Glendale Hotel & Conference Center, 9495 Entertainment Boulevard, Glendale, Arizona 85305, from June 8–11, 2025. Visit us at Booth 201 to explore our advanced polymer solutions, including two-component structural polyurethanes for concrete leveling and void fill and one-component polyurethanes for soil stabilization and leak seal, addressing infrastructure challenges like cracked pavement, sinking slabs, leaking culverts, and unstable soil for DOT and airport projects.

Learn How Alchatek Helps You

At Booth 201, you can meet with our experts to learn how Alchatek supports your infrastructure initiatives with our environmentally friendly NSF/ANSI/CAN 61-certified technologies.

We benefit engineers in three key ways:

• Connections with Experienced Contractors: We partner you with skilled, vetted contractors trained in our advanced polymer solutions for high-quality project execution.
• PDH Credit Lunch and Learn Presentations: We offer in-office presentations providing Professional Development Hours (PDH) credits, equipping your team with the latest geotechnical and infrastructure repair techniques.
• Assistance with Project Specifications: Our experts collaborate to develop precise, project-specific specifications, ensuring compliance and optimal performance.

Want more information on Alchatek products?

Download the Info-Packed Geotech Product Catalog!

Download the Info-Packed Leak Seal Product Catalog!

The City of Sand Springs, Oklahoma, identified a foundation leak in Bay 10 of the Shell Lake Dam, necessitating repairs to ensure the dam’s structural integrity. The city’s Public Works Department contracted with a qualified firm to address the issue, and Keithline Engineering Group was retained to provide engineering design and oversight for the project.

Initial Assessment

An inspection by Keithline Engineering revealed an active boil, or leak, in the concrete footing of Bay 10. The leak, measuring approximately 5” by 7”, exhibited increasing water movement and was deemed a priority for repair. The engineering team determined that the water was likely traveling between the concrete footing and the porous sandstone underlayment before exiting through the hole in the concrete. This leak was transporting a small amount of material under low pressure. It was also determined the owner had made prior unsuccessful attempts to seal the area with bentonite.

Proposed Solution

After consulting with Alchatek, Keithline Engineering specified a leak-sealing solution centered around the injection of Spetec PUR H100. Alchatek recommended this hydrophobic polyurethane grout for its ability to expand and create a dense, impermeable seal upon contact with water. The repair strategy involved drilling through the concrete and injecting the grout into the concrete/sandstone interface to create a grout curtain. This approach aimed to stop the leak at its source and prevent further water migration.

Procedures

1. Preparation:

• Hammer-drilled 1/2-inch injection ports were installed into the concrete foundation at designated locations.
• Saturated oakum rope or hydraulic cement was applied to temporarily plug the hole during the injection.

2. Injection Process:

• Spetec PUR H100 was injected through installed packers using positive displacement pumps.
• Injection proceeded until the grout formed a complete polyurethane barrier around the boil and stopped water infiltration.
• The process included monitoring grout expansion and ensuring proper confinement within the concrete/sandstone interface.

3. Post-Sealing:

• Following the injection, all nipples were removed, and drilled holes were patched with hydraulic cement to a minimum depth of 12 inches.

Results and Conclusion

The injection grouting successfully sealed the foundation leak in Bay 10 of Shell Lake Dam. Spetec PUR H100 formed a durable polyurethane barrier, effectively stopping water flow and preventing further erosion of material from beneath the dam footing. The swift and effective repair was achieved in a matter of hours. Restek, Inc. precisely executed the specifications. The result is a solution that preserves the long-term structural integrity of the Shell Lake Dam, showcasing the value of proactive maintenance in preserving critical water resources.

Want more information on polyurethane leak seal materials?

Download the Info-Packed Leak Seal Product Catalog!

A Utah-based geotech specialist partnered with a general contractor to address a critical DOT infrastructure challenge involving the replacement of an existing culvert on a major roadway in Utah. The project involved the installation of precast concrete slabs on both sides of the box culvert, designed to create a seamless transition from the culvert to the compacted road base.

Site Investigation and Challenge

During the design phase, engineers identified that constructing a compacted road base beneath the slab would inevitably leave voids underneath. These voids posed a risk of uneven support and potential rocking of the slab when subjected to heavy traffic load.

Proposed Solution

To address this, ¾” holes were drilled four feet apart to allow for injection rods to be inserted through the slab. The foam selected for this slab was AP Lift 440 structural foam due to its rapid expansion and high strength needed for DOT projects. This foam expands 17-19 times its original volume within 8-10 seconds of injection, ensuring comprehensive void filling. Dial indicators were used to ensure that there was no vertical movement of the slab during the injection process.  

Results and Conclusion

The entire operation was executed in approximately three hours, utilizing about 400 lbs of structural foam. This successful application filled all of the voids, providing uniform support for the precast slabs and enhancing overall road stability. The rapid curing properties of the foam allowed for swift project completion with minimal disruption to traffic.

Want more information on stabilizing soil with polyurethane?

Download an Info-Packed Soil Stabilization Brochure!

Mid South Concrete Lifting successfully executed an emergency repair operation at a Tennessee Valley Authority (TVA) lift station in New Johnsonville, Tennessee. What began as a new construction project quickly required an urgent repair when significant leakage was discovered at multiple joint locations immediately after installation. The contractor's rapid response and innovative solution prevented extensive water loss and potential environmental impacts.

Initial Assessment

The investigation began when facility managers discovered several critical issues:

• Structural weaknesses detected in multiple joint locations
• Massive water loss occurring within 24 hours of installation
• Thousands of gallons of water escaping through compromised joints
• Environmental concerns due to uncontrolled water discharge

The severity of the situation demanded emergency intervention to prevent continued water loss and potential damage to surrounding infrastructure.

Proposed Solution

After technical evaluation, Spetec PUR F400 was selected as the optimal solution due to its superior characteristics:

• Rapid-curing formulation for quick deployment
• Excellent adhesion properties for joint sealing
• Water-reactive chemistry suitable for wet conditions
• High structural strength for long-term durability
• Environmental compatibility for water infrastructure

Procedures

1. Complete dewatering of the lift station
2. Technical team rappelled into the structure
3. Systematic injection of Spetec F400 at all compromised joints
4. Progressive sealing to ensure complete joint stabilization

Results and Conclusion

The emergency repair proved successful on multiple fronts:

• Complete elimination of water loss through compromised joints
• Restoration of structural integrity to all sealed areas
• The system returned to full operational status within 24 hours
• Long-term solution achieved with minimal downtime
• Cost-effective resolution compared to alternative repair methods

The project demonstrated the effectiveness of chemical grout injection as a rapid response to critical infrastructure leaks. It successfully prevented ongoing water loss while providing a durable, long-term repair solution.

Want more information on sealing leaks with polyurethane?

Download an Info-Packed Leak Seal Brochure!

Suburban Basement was hired to address significant voids beneath a slab foundation residence in Roseville, Michigan. The voids were suspected to have been caused by a compromised sewer line under the bathroom shower, resulting in extended leakage affecting a substantial portion of the home’s foundation. After plumbers discovered the issue, a local property restoration company managing the overall project engaged Suburban Basement.

Initial Assessment

The extent of the voids was assessed using 4-foot-tall plow markers as probes. The voids almost entirely engulfed these probes, indicating severe foundation undermining. The situation required a solution that could effectively fill large voids, bond with both soil and concrete, and perform well in wet environments.

Proposed Solution

Suburban Basement proposed using Alchatek's AP Lift 430 for the void filling. This material was chosen for its high expansion rate, making it cost-effective for large voids. Its ability to bond with soil and concrete, perform in wet conditions, and displace residual moisture from the plumbing leak made it ideal for this application.

Procedures

1. Drilled a systematic grid pattern of holes throughout the residence
2. Employed controlled injection shots to avoid excessive product usage and prevent lifting
3. Carefully filled all voids without causing any lifting of the foundation

Results

The project restored the foundation's integrity, filling all voids within a day. This efficient execution led to significant time and cost savings for all parties. The insurance company reduced relocation expenses, the restoration company delivered ahead of schedule, and the homeowners returned to their structurally sound homes earlier than expected. The outcome satisfied all stakeholders, demonstrating the effectiveness of the chosen solution in addressing complex foundation issues promptly and efficiently.

Want more information on geotechnical polyurethanes?

Download the Info-Packed Geotech Product Catalog!

An old farmhouse with a wrap-around porch in Lake Orion, Michigan, presented a unique challenge. Beneath the porch lay an old cellar, initially used for coal storage but now serving only as a conduit for a well line into the residence. The primary concern was the inward buckling of the cellar walls, which posed a significant safety hazard. Many contractors suggested demolishing the porch and excavating the cellar, a solution that would have incurred substantial costs for both demolition and reconstruction.

Initial Assessment

Suburban Basement was engaged to address this issue. Upon evaluation, the team identified a more cost-effective and less invasive solution. The cellar, measuring 12 feet in length, 5 feet in height, and 5 feet in width, could be filled with foam to mitigate the risk of further wall collapse. This approach would spare the property owner the expensive and disruptive process of demolition and reconstruction.

Proposed Solution

The team proposed filling the cellar with Alchatek’s AP Lift 430 foam. This material was chosen for its extensive expansion rate, superior compressive strength, and lower application temperatures. These properties allowed for quicker application intervals while maintaining optimal temperatures between applications and minimizing ignition risks.

Procedures

1. Encapsulated the well line with sonotubes elevated above the cellar floor, ensuring future accessibility.
2. Installed OSB sheathing to define foam boundaries and prevent overflow.
3. Applied AP Lift 430 in layers, allowing cooling intervals between applications to optimize expansion and stability.
4. Coordinated with masons to prepare for CMU block installation at the containment boundary, ensuring seamless alignment with the existing foundation.

Results

The foam-filling solution successfully stabilized the cellar walls, eliminating the collapse risk while preserving functionality. Compared to traditional approaches, this method saved the client approximately $25,000 and maintained the home’s historic features. Completed in just five days, the project significantly outpaced conventional methods. Homeowners were highly satisfied with the noninvasive approach, cost savings, and seamless integration with their property’s historic character, demonstrating the effectiveness of innovative techniques in addressing complex structural challenges in historic properties.

Want more information on geotechnical polyurethanes?

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Suburban Basement was contracted to address a multifaceted water intrusion issue on a Rochester Hills, Michigan property. The basement had water ingress from both the furnace ductwork and the foundation. The ductwork, extending through the foundation wall into a garage-adjacent wall cavity, had sections below grade behind a garage curb. The root of the problem was water pooling under the back curb, caused by settled garage slabs from the main vehicle entrance.

Initial Assessment

The project was divided into two phases: first, addressing the leaking foundation and furnace ductwork, and second, void filling and concrete leveling of the garage floor and curb. The complexity arose from the undermined garage slabs and the need to prevent water intrusion while ensuring the safety of the furnace ductwork.

Proposed Solution

For the initial water intrusion, Suburban Basement proposed using Alchatek’s Spetec PUR Highfoamer for curtain grouting, given the limited accessibility and its fast reaction time. For the concrete leveling and void filling, AP Lift 430 was selected due to its expansion rate, soil stabilization capabilities, water displacement properties, and quick curing time for vehicle traffic.

Procedures

1. Applied curtain grout to the positive side of the wall to stop water intrusion and encapsulate the dual wall furnace ductwork
2. Commenced void filling and leveling at the garage curb, progressing toward the main vehicle entrance
3. Filled all voids beneath the garage curb and leveled the concrete across all areas of concern
4. Conducted water tests to ensure all leaks were addressed before proceeding to phase two
5. Performed void filling and concrete leveling, displacing significant amounts of water near the main vehicle entrance

Results

The project was completed successfully in two phases, with the curtain grouting finished within hours and the void filling and concrete leveling taking approximately half a day. All leaks were effectively stopped, and the concrete was successfully leveled. The homeowner expressed high satisfaction, notably as previous repair attempts had failed. Suburban Basement’s solution not only resolved the immediate water intrusion problems but also extended the lifespan of the garage concrete and driveway, providing a comprehensive fix to a complex issue.

Want more information on leak seal and slab lifting?

Download an Info-Packed Leak Seal Brochure!

Download an Info-Packed Slab Lift Brochure!

Management at a luxury hotel in Atlanta contacted geotech specialists Panhandle Seawall and Infrastructure after discovering significant voids beneath their swimming pool during routine maintenance. What began as a standard pool inspection quickly escalated into a serious structural emergency that threatened the integrity of part of the building. PSI was able to mobilize within days, providing temporary support until the foundation contractor could underpin the column footing and provide a permanent solution.

Initial Assessment

The investigation began when hotel maintenance staff noticed several concerning issues:

• Visible cracks developing in the pool structure.
• Accelerated water loss beyond normal evaporation.
• Significant increase in monthly water bills.
• Further investigation revealed an approximately 800 cubic foot void beneath the pool.
• A critical structural issue where a column footing was precariously supported only by the edge of a rock formation.

The severity of the situation led to a partial condemnation of the hotel structure, requiring immediate intervention to prevent potential catastrophic failure.

Proposed Solution

After careful evaluation by the project engineers, AP Lift 475 was selected as the optimal solution due to its superior characteristics:

• Higher density formulation for enhanced structural support.
• Superior bearing capacity to meet engineering requirements.
• Rapid deployment capabilities for emergency situations.

The project required approximately 300 gallons of material, deployed in three separate sets, to provide the necessary structural reinforcement.

Procedures

1. Safety Implementation

• Installation of proper ventilation systems.
• Deployment of temporary support beams.
• Setup of adequate lighting for the work area.

2. Grout Implementation

• Initial deployment of the Deep Lock® method to solidify underlying soil.
• Systematic void filling through carefully timed injection intervals.
• Continuous monitoring of material flow and structural response.
• Progressive filling to ensure complete void elimination and stabilization of footing.

Results and Conclusion

• The emergency shoring proved successful on multiple fronts:
• Complete stabilization of the compromised column footing.
• Establishment of solid connectivity between the underlying soil and structural elements.
• Prevention of further structural degradation.
• Removal of condemnation threat to the building.
• Restoration of structural integrity to engineering standards.

The project demonstrated the effectiveness of polyurethane void fill as a rapid response solution for critical structural emergencies, successfully averting potential building failure while providing a long-term stabilization solution.

Want more information on geotechnical products and equipment?

Download the Info-Packed Geotech Product Catalog!

The owner of a gas manufacturing facility contacted a Georgia-based contractor regarding significant floor settlement issues, with a warehouse slab dropping approximately 3-4 inches. The settlement made issues for the forklift traversing in and out of the warehouse and posed a risk to the workers.

Initial Assessment

Upon arrival at the site, the team conducted a thorough investigation. Using a probe, voids were identified beneath the slab, with the probe sinking up to 2 feet in some areas. A Dynamic Cone Penetrometer test revealed large voids 2-4 feet below the slab.  Poor drainage was evident, with improper crowning causing water to flow towards the building instead of away from it. Interestingly, a layer of unusually hard clay was noticed outside the building, suggesting possible prior remediation attempts.

Proposed Solution

AP Lift 430 was chosen for this project, providing an excellent injectable polyurethane grout solution. With its impressive 22x expansion capability and 7,200 psf compressive strength, it’s ideal for warehouse slabs that support heavy equipment. The grout’s hydrophobic properties ensure long-term stability by blocking water infiltration that could otherwise lead to void formation.

Procedures

1. Deep Injection (Void Fill)

• 32 injection points were established in a grid pattern (16 on each side) at 4 ft apart.
• At each point, the team injected 15-20 pounds of material at about 5 feet depth.
• A slight lift (approximately 1/16 inch) during this phase indicated successful void filling.

2. Slab Lifting

• Additional holes were drilled next to the wall, 3 feet from the wall, and 9 feet from the wall (6 feet from the first row).
• Injection began from the holes nearest to the wall and moved outward.
• Multiple passes were made, with some areas requiring 3-4 injections.
• Gradual lifting was employed to prevent slab cracking.
• Dial indicators were used to ensure even lifting across the warehouse floor.

Results

The project successfully stabilized the warehouse floor and restored it to its proper level. Effective void-filling addressed the underlying instability, providing a solid foundation for the slab. Success was evident in the restored functionality of the warehouse space and the elimination of safety hazards posed by the uneven floor. The property manager was pleased with the work and requested additional slab lifting services for their other facilities.

Want more information on lifting slabs with polyurethane?

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