Alchatek Blog

A concrete staircase in a prominent mixed-use complex in Atlanta needed urgent repairs due to a set of 75-foot-long sunken steps. This issue posed a significant trip hazard, potentially compromising visitor safety. The problem stemmed from a combination of factors working together over time. Water infiltration through expansion cracks had created voids beneath the stairs, weakening their foundation. Compounding this issue was the natural tendency of separate concrete pieces to expand and contract, moving independently. This movement was particularly problematic as it caused the steps to separate from the adjacent sidewalk. Over time, the repeated cycles of expansion and contraction, coupled with the underlying voids, led to the steps sinking and rolling, creating a hazardous situation. 

Local experts from Engineered Restorations were called in to tackle this tricky situation. The team faced the challenge of addressing safety concerns while preserving the structural integrity of the staircase.

Powerful Polymers

AP Lift 430 was selected as the repair material for this restoration project. This polyurethane foam has expansive properties that are suitable for lifting sunken structures. Once cured, AP Lift 430 provides support for long-term stability, aligning with the project's requirements.

Painless Procedures

The repair process began with an assessment of the trip hazard. This allowed the team to determine the extent of the problem and plan their approach. Next, backer rods between the steps and sidewalk were removed to prepare the area for treatment. Alchatek Surface Guard 125 was applied around the injection area to prevent any excess polyurethane from bonding to the concrete. Protective sheets were placed to shield nearby glass surfaces.

The team drilled holes through the 8-inch concrete steps to reach the underlying soil. Soil probes revealed firm underlying conditions. The team then implemented their injection strategy. They created an initial foam layer slowly, injecting it just once every ten seconds. This gradual approach prevented existing hairline cracks from expanding during the lifting process. The team continued to inject AP Fill 430 until the steps were level. Finally, they redrilled and applied a second injection layer beneath the first to fill any voids created in the process. New backer rods were then installed.

To enhance the longevity of the repair, the team took an additional crucial step. They sealed the expansion joints with silicone, creating an optimal water barrier. This silicone sealant is flexible, accommodating future expansion and contraction. This extra measure was designed to protect the structure from water infiltration and movement, addressing the root causes of the original problem. 

Rapid Results

In just four hours, the steps were restored to a level position, aligning with the adjacent walkway. This efficient repair method addressed the immediate safety issue while extending the structure's lifespan. By lifting the existing steps rather than replacing them, the property owner avoided substantial expenses associated with demolition, new materials, and extended labor time for a complete replacement. This approach ultimately provided significant cost savings.

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Essential Details

Dates/Pricing

Geotechnical Masterclass: March 25th - 27th, 2025

$695.00
This is special pricing for all who register before the end of day, February 25th. $745 February 26th and later. ($50 discount for each additional participant.)

Location

To Be Determined
(in Georgia)

Discount

$50 discount for each additional participant.

Geotechnical Masterclass

Elevate your geotechnical expertise with our comprehensive masterclass covering cutting-edge techniques and solutions. Master:

• Polyurethane Concrete Leveling for sunken slabs
• Polyurethane Soil Stabilization for various soil types
• Geotechnical Testing with precision
• Deep Lock® soil stabilization procedures

Why Attend?

• Gain Hands-On Experience with state-of-the-art equipment
• Learn From Industry-Leading Experts with decades of experience
• Network with Peers and potential collaborators
• Boost Your Company’s Market Reach and capabilities

Consider the low cost of training vs. the high cost of job screw-ups and missed opportunities.

Transitioning from routine geotechnical work to more complex and high-stakes infrastructure and large-scale construction projects represents a significant growth opportunity for your career and business. Get the advanced skills and critical insights needed to tackle challenging projects and succeed in competitive markets confidently.

Join us for this transformative Geotechnical Masterclass. We’ll equip you with the knowledge and techniques to excel across all geotechnical project types.

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 lay at an angle, and if a strong wind is coming from one direction, it can try to “lift” the panel and pile.  Conversely, a strong wind coming from the opposite direction creates a downward force and can drive the supporting pile into the soil.

Powerful Polymers

The general contractor contacted the grouting specialists at Stable Soils and asked if they could use cement grout to try and lock the piles into place. Because of the tight confines between rows of piles, the specialist suggested a polyurethane permeation grout, Alchatek's AP Soil 600. The required installation equipment is more compact and it is a lot cleaner to install than cement. 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.  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. As the AP Soil 600 soaks into the damp sand, it reacts and produces carbon dioxide.  The CO² creates a swelling effect, driving the resin further into the sandy soil.

Painless Procedures

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.  About 1/3 of the piles received 1-1/2 gallons.  Another third received 1 gallon, and the final third was injected with 3/4 of a gallon.  All of the piles passed the pull testing and compression testing.  The project was awarded, and around 4000 piles were injected in total.  It was a complete success.

Fast forward to 2022 at a massive solar field installation in Ft. Green, Florida.  Like many solar fields, it was not necessarily 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 wanted the proposed 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 was provided, to their satisfaction.

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

For this installation, the same three different volumes of AP Soil 600 were tested.  Once again, only 3/4 of a gallon was deemed sufficient to pass the testing, so that was what was used.  5000 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.

Rapid Results

In the Fall of 2022, disaster struck Ft. Green, a location unfortunately positioned directly in the path of a Category 3 hurricane. The storm’s ferocity was evident as it swept through, leaving behind 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 proved too powerful, driving piles of solar panels into the ground. Despite their robust design, many panels were shredded, and a significant number of the piles suffered movement, highlighting the sheer force of nature’s fury.

Out of 5000 piles injected, only 9 showed any sign of movement.  The polyurethane grout was put to the test and passed with flying colors.  Currently, this field is going through the insurance claim process, but the testing for the repair method has already been completed.  The embedded piles were jacked back up to level and then grouted in place with AP Soil 600.  All of them passed the test; now, the field is waiting for the insurance to be worked out so the rest of the damaged piles can be glued 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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The owners of a college apartment complex in Georgia reached out to a local engineering firm after discovering a large void underneath the northwest end of the building. The issue was caused by stormwater collecting and flowing beneath the building's foundation. Over time, the foundation became exposed and now the grade has lowered by a foot from the original design.

Site Investigation and Initial Attempts

A dynamic cone penetrometer test revealed the soil was fragile, with two to three blow counts for the tested areas. Underpinning piles had been installed by the previous owner, but did not did not adequately stabilize the building's foundation. The shifting foundations caused the ceiling and wall in one of the top-level rooms to begin to crack and showed early signs of separation.

Proposed Solution

The engineering team recommended using injectable polyurethane grout. AP Lift 430 was selected for the job because of its high expansion of 22x and compressive strength of 7,200 psf. This polymer is also hydrophobic, which prevents water from causing further erosion of the void.

Implementation

1. Rod Placement: Injection rods were inserted horizontally into the void’s back, spaced 4 feet apart.
2. Foam Injection: Foam was injected through the rods until emerging from the exposed void area. This step ensured that the foam reached the farthest areas of the cavity.
3. Free-Shooting: The remaining exposed void was filled by direct foam application, ensuring comprehensive coverage.

Results and Conclusion

The end result was 658 gallons of expanded AP Lift 430 injected underneath the void. The polyurethane injection, combined with regrading work done in collaboration with a local engineering firm, successfully solved the issue and prevented further void formation underneath the student housing.

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Foundation foam is a trusted solution for engineers and contractors addressing soil stabilization and structural support challenges. This proven technology effectively tackles issues caused by unstable soil, from erosion to poor compaction. Over the years, it has established itself as an essential tool for maintaining the integrity of buildings, roads, and other infrastructure.

Why Soil Stability Matters

Unstable soil poses significant risks to structures built upon it. For instance, erosion, poor compaction, and freeze-thaw cycles can lead to settling, cracking, and even catastrophic failure. Moreover, these issues often occur deep beneath the surface, making them difficult to address using traditional methods. Therefore, reliable solutions are crucial for ensuring long-term structural integrity.

The Power of Foundation Foam

Foundation foam offers a dependable solution to these challenges. Unlike conventional methods, it can be injected deep into the soil without heavy excavation equipment, allowing for precise soil stabilization and compaction. Furthermore, the foam cures quickly. This rapid curing time significantly reduces project downtime and improves overall efficiency.

One-Component Standard Soil Stabilization

One-component foundation foam products offer durable and effective solutions for standard soil stabilization projects. These products are perfect for soil permeation, spreading through, and strengthening loose or unstable soil.

• AP Soil 600
• AP Fill 700
• AP Fill 720

Their ability to permeate soil makes them excellent choices for addressing issues like erosion, poor compaction, and water infiltration. As a result, these one-component foundation foam solutions can effectively stabilize soil without requiring extensive excavation or heavy machinery.

Two-Component Deep Lock® Stabilization

The Deep Lock® process utilizes two-component foundation foam products for deep soil issues. These include:

• AP Deep Lift 420
• AP Lift 430
• AP Lift 440
• AP Lift 475

The Deep Lock® process allows for soil stabilization at greater depths, thus making it particularly useful for large-scale projects or structures with significant foundation issues. Additionally, this method can achieve soil stabilization and compaction with minimal surface disruption.

Versatility in Application

One of the critical advantages of foundation foam is its versatility. It can be used in a variety of scenarios, including:

• Supporting settled buildings
• Enhancing soil density around pipes and tunnels
• Reinforcing bridge approach slabs
• Strengthening port and airport infrastructure

Foundation foam provides long-lasting support and protection against future settling or erosion in each application. Consequently, it has become a go-to solution for many construction and rehabilitation projects.

Comparing Foundation Foam to Traditional Methods

Compared to traditional soil stabilization methods, foundation foam stands out in several ways. For example, cement pressure grouting requires heavy equipment and can be messy and imprecise. Similarly, helical piers and push piers, while effective, are often more invasive and limited in their application.

In contrast, foundation foam is less invasive, faster to install, and addresses underlying soil issues more comprehensively. Moreover, it can be combined with other methods for even more effective results. Therefore, it offers a more flexible and efficient solution for many soil stabilization projects.

Environmental Considerations

An important aspect of foundation foam is its environmental safety. Alchatek foundation foams are NSF-certified to strict ecological standards. This certification ensures that the cured foam won't negatively impact groundwater quality. As a result, these foundation foams are a responsible choice for projects in environmentally sensitive areas. This rigorous environmental compliance further enhances their appeal as a trusted soil stabilization solution.

Long-Term Benefits

The long-term benefits of foundation foam are substantial. Once cured, the foam creates a stable, water-resistant barrier lasting decades. This longevity translates to reduced maintenance costs and improved structural integrity over time. As a result, property owners can enjoy peace of mind knowing their investments are protected for years to come.

A Solid Foundation for the Future

Consistently providing an effective solution to soil issues, foundation foam has proven instrumental in ensuring the longevity and safety of buildings and infrastructure worldwide. With its track record of success, foundation foam continues to be a go-to choice for construction and rehabilitation projects of all sizes. This time-tested technology remains at the forefront of creating stable and resilient structures for the present and future.

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Are you a geotechnical contractor facing challenges with unreliable lifting foam that leads to costly callbacks? You can significantly reduce these issues by choosing quality lifting foam from a manufacturer focused on slab lifting applications. The right solution makes all the difference in achieving consistent, successful results.

The Painful Costs of Job Callbacks

The financial impact can be severe when callbacks occur due to subpar lifting foam. You can lose revenue when you have to redo jobs without additional payment. Meanwhile, new project starts may be delayed, creating a ripple effect throughout the schedule. As a result, resource allocation becomes inefficient, further straining the business.

Impact on Business Reputation

Low-quality foam products can severely damage customer relationships. Negative online reviews may start appearing, which can hurt your lead-generation efforts. Property managers and other repeat customers may look elsewhere for future projects. Moreover, the likelihood of receiving valuable referrals decreases substantially. In this competitive industry, maintaining a solid reputation is essential for long-term success.

Benefits of a Specialized Manufacturer

Choosing a manufacturer focusing exclusively on polyurethane for slab lifting makes a notable difference. Specialized manufacturers maintain rigorous quality control standards throughout the production process. Furthermore, this dedicated approach ensures that you receive consistent results with every application. This approach provides better outcomes than relying on a general foam manufacturer who could be producing everything from spray foam insulation to material for couch cushions.

Quality Lifting Foam: The Foundation of Success

Reliable quality lifting foam leads to satisfied customers and more substantial business growth. With proper materials and consistent results, contractors can build lasting relationships with repeat customers while maintaining a solid reputation in the industry. 

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Winter weather creates unique challenges for polyurethane slab lifting operations. As temperatures drop, proper equipment care becomes essential for successful projects. Here are vital tips to keep your rig running smoothly during cold weather and properly stored at season's end.

Cold Weather Operation Essentials 

Operating in cold conditions requires specialized heating equipment. The proper function of the pump's A/B preheaters and the hose heater is the biggest factor for pumping in cold weather. Without these heaters, the material cannot warm up or stay warm. Additionally, heated hoses with copper coils or internal wiring keep material flowing smoothly through the system.

Temperature Management Strategies 

Maintaining the correct material temperature is crucial for optimal performance. Therefore, barrel temperatures should stay between 70° and 80° Fahrenheit. During winter months, achieving these temperatures takes longer due to overnight cold. Consequently, keeping barrel heaters running overnight can help maintain proper temperatures. Most importantly, regular material recirculation ensures consistent heating throughout the system.

Winter Storage and Maintenance 

Proper end-of-season maintenance protects your investment. Flush the pump system thoroughly with Alchatek Pump Flush until all iso discoloration disappears. Run the end of the hose through cheesecloth to catch crystallized iso particles. Finally, fill the system with Alchatek Pump Saver 195 for long-term storage. For detailed step-by-step instructions, contact the Alchatek support team at 404-618-0438.

Safety First: Winter Precautions 

Safe winter operations require proper protective equipment. Start with appropriate goggles and a respirator. Furthermore, always work in well-ventilated areas to ensure adequate air circulation.

Expert Support When You Need It 

Cold weather operations can present unexpected challenges. Contact Alchatek's technical support team at 404-618-0438 for specific questions or detailed guidance.

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Water leaks in concrete slabs can be a severe issue for property owners. These leaks occur when water from the ground seeps through cracks or gaps in the concrete foundation, leading to moisture problems inside the building. If not addressed promptly, these upward-moving leaks can lead to structural issues, damage flooring materials, and create an environment conducive to unhealthy mold growth. Curtain grouting with polyurethane is a proven technique for effectively fixing water leaks in concrete slabs. This method creates a barrier beneath the slab, preventing water from penetrating upwards and resolving the issue at its source.

The Curtain Grouting Solution

Curtain grouting is a well-established and highly effective method for addressing water leaks in concrete slabs. The process begins with drilling small holes through the concrete slab in a precise diamond grid pattern. Technicians then inject polyurethane grout into each hole, overlapping injections like shingles on a roof to ensure comprehensive coverage. Upon contact with water from the leak, the grout expands and forms a solid, watertight barrier beneath the slab. This durable seal effectively prevents further water intrusion, resolving the leak at its source.

Advantages of Curtain Grouting

This technique can address multiple leaks simultaneously, providing a comprehensive solution. Additionally, it delivers long-lasting results, ensuring the integrity of your slab for years to come. The process requires minimal equipment and causes less disruption compared to other methods. Moreover, the materials used in curtain grouting are environmentally safe and NSF-certified to meet strict environmental standards.

The Critical Role of Professional Expertise

Fixing a water leak in a concrete slab is not a task for DIY enthusiasts. Due to the complexity of the process, professional expertise is crucial. Experienced contractors possess specialized equipment and materials necessary for effective curtain grouting. Their expertise allows for accurate diagnosis of the leak's extent and location. Proper curtain grouting application requires precise techniques that professionals have honed through years of experience. Furthermore, experienced contractors provide comprehensive repairs that address not just the symptoms but the root cause of the leak.

Fixing Water Leaks in Concrete Slabs

Water leaks in concrete slabs seriously threaten your home's structural integrity. Understanding the problem and seeking professional help promptly are critical steps in addressing these issues effectively. When performed by experienced contractors, curtain grouting offers a reliable and time-tested solution to fix water leaks in concrete slabs. You can ensure your home's long-term stability and safety by taking swift action and relying on professional expertise.

Fill out this form or call 404-618-0438 for a contractor referral today!

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A critical infrastructure issue emerged on a four-lane road near downtown San Francisco. Soil erosion caused a bridge approach slab to settle 2.5 to 3 inches over time. The affected area had an asphalt surface with a thin sleeper slab underneath. California Department of Transportation (Caltrans) engineers initially advocated for complete replacement. The situation changed when Bay Area Underpinning entered the scene. Together with Alchatek, they presented an alternative solution: Deep Lock® soil stabilization and concrete leveling. After careful consideration, the DOT engineers agreed to try this innovative approach. This method promised to minimize traffic disruption and significantly reduce costs compared to full replacement, which would have required closing the entire roadway and replacing a 40x12 foot area of asphalt and sleeper slab.

Powerful Polymers

The project team chose AP Lift 475 as the repair material. This substance offers impressive compressive strength while maintaining good expansion properties. Once injected, the material spreads out effectively, filling voids in the annular space within the soil. This combination of strength and expansion makes AP Lift 475 ideal for stabilizing and leveling the settled bridge approach slab. The material's ability to penetrate and fill voids addresses the underlying cause of the settlement, providing a more comprehensive solution than - for example - simply adding a new surface layer.

Painless Procedures

Before starting the repair, DOT engineers conducted thorough soil testing. They performed soil borings to determine soil types and characteristics at various depths. This crucial step provided insights into the subsurface conditions contributing to the settlement. Additionally, they used a DCP (Dynamic Cone Penetrometer) test to identify areas of weak soil density. Armed with this information, the contractor developed an optimal application plan.

The team installed injection tubes on four-foot centers at six- and 10-foot depths. They injected about 40 pounds of material per tube, using 10-15-second shots. This measured approach allowed for controlled material distribution. Throughout the process, the team carefully monitored the slab lift using a rotary laser and zip-level altimeter. These precise instruments ensured even raising of the slab to the desired level, preventing any potential issues from uneven lifting.

Rapid Results

The modular approach to repair minimized traffic disruption, a critical factor for this busy thoroughfare. At any given time, only two out of four lanes remained closed. Consequently, traffic continued to flow throughout the project, preventing gridlock in the area. The team completed the entire leveling process in just four eight-hour shifts, a remarkably short timeframe for such a significant repair. Compared to full replacement, the method significantly cut labor requirements, traffic disruption, and financial costs. Moreover, the repair addressed the root cause of the problem by stabilizing the eroded soil beneath the roadway.

Unlike simply adding an asphalt layer for leveling, which would have provided only a temporary fix, this solution offers long-lasting results. By directly treating the underlying issue, the team greatly reduced the likelihood of recurrence. The success of this project offers a blueprint for similar infrastructure challenges. It showcases how modern materials and techniques can provide cost-effective, efficient, and durable solutions to complex engineering problems. 

Want more information on Deep Lock® soil stabilization and slab lifting?

Polyurethane slab lifting effectively restores sunken concrete surfaces. This process relies on specialized slab jacking equipment, enabling contractors to perform precise and efficient repairs. This overview will explore the fundamental tools for successful polyurethane slab lifting operations.

Slab Jacking Equipment Rigs

Firstly, let's consider the most popular slab lifting rig options. V-nose trailers (16-20 feet) and Box Truck Build-Outs (16-28 feet) are the most common choices for polyurethane contractors. These rigs provide ample space for storing and transporting essential equipment and materials to various job sites. The flexibility of these mobile setups allows contractors to easily adapt to different project scales and locations.

Slab Lifting Pumps

Moving on to slab lifting pumps, PMC plural component hydraulic proportioners play a crucial role in polyurethane slab jacking. These reliable pumps are designed to inject two-component structural foams effectively. Additionally, they utilize relays and circuit breakers instead of circuit boards, thus enhancing reliability and reducing maintenance issues. The rugged construction of these pumps ensures they can withstand the demanding conditions often encountered in concrete leveling projects.

MixMaster Pro Slab Lifting Gun

Furthermore, the MixMaster Pro slab lifting gun is manufactured explicitly for concrete leveling. It's built to handle high back pressure and has a durable stainless steel construction. Moreover, its integrated rebuildable check valves protect the whip hose, lowering replacement costs. The gun's mechanical actuation system eliminates the need for side seals or O-rings in the mixing block, further simplifying maintenance and increasing reliability.

PolyBadger Mobile Lifting System

The PolyBadger lifting system is an excellent option for contractors seeking a compact solution. Its auto-calibrator ensures precise component ratios, thereby preventing mix-up issues. Notably, this system can fit in a pickup truck, making it highly portable for various job sites. The PolyBadger's versatility makes it ideal for both beginning slab lifting contractors who want to start with a smaller, more affordable unit and experienced professionals looking to add a compact system to their arsenal for hard-to-reach locations.

Jack Attack Manual Slab Lifting System

The Jack Attack system proves invaluable when dealing with small to medium slabs. This leverage device, featuring a triangular steel frame and an 8000 lb jack, allows for accurate slab positioning during polyurethane injection. As a result, it significantly simplifies complex repairs. The system's design enables a single operator to manipulate slabs efficiently, reducing labor requirements and improving overall project efficiency.

Dynamic Cone Penetrometer for Soil Testing

Assessing soil strength before beginning polyurethane injection can be crucial. The Dynamic Cone Penetrometer (DCP) offers a portable solution. Consequently, the data gathered helps develop effective injection plans and accurately estimate material usage. Many municipalities and agencies recognize DCP testing as a valid method for soil strength assessment, potentially opening up additional revenue streams for contractors.

Stain Prevention with AP Surface Guard 125

Lastly, many contractors use AP Surface Guard 125 to prevent staining during slab jacking. This water-based barrier protects concrete surfaces from polyurethane resin stains. Additionally, it serves as a flushing agent for cleaning the MixMaster gun block, thus offering a dual-purpose, environmentally friendly solution. Its biodegradable nature aligns with growing environmental concerns in the construction industry.

Polyurethane Slab Jacking Equipment

In conclusion, as slab jacking equipment continues to evolve, polyurethane contractors gain access to more efficient and precise tools for concrete repair. Professionals can deliver high-quality results by understanding and utilizing these specialized tools while optimizing their operations across various projects. The ongoing development of slab jacking equipment underscores the industry's commitment to improving concrete restoration techniques and outcomes.

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