In the realm of grouting, patience and a methodical approach are key to achieving optimal results. This is particularly true when it comes to the concept of stage grouting, a technique that ensures effective curtain grouting with polyurethane.

The Concept of Stage Grouting

Stage grouting is not about pumping a predetermined amount of grout into a hole. Such an approach would result in the grout pushing away from the wall, which is not the desired outcome. The goal is to keep the grout close to the wall, as the purpose of this process is waterproofing, not soil modification or permeation grouting.

The Methodology of Stage Grouting

The stage grouting process begins with a cup test to determine when the grout starts to react and turn into foam. Typically 45 seconds to a minute is a good time but adjust as necessary for field conditions. At this point, it is recommended to pump a small amount of grout, perhaps a third or even a quarter of the planned total, into the hole. After that initial amount begins to react, another burst of grout is pumped in, and the process is repeated. The aim here is to slowly build a foam mass on the backside of the wall. This foam mass, once formed, will hold the new grout against the wall, allowing it to travel vertically or horizontally. This is the desired outcome, as it facilitates communication between the ports or holes drilled into the wall.

The Importance of Stage Grouting

Stage grouting is a crucial technique in curtain grouting. Many issues arise when too much material is used without significant impact. Stage grouting allows for careful monitoring and slow, methodical application, ensuring that the grout is effectively used and serves its purpose. If, after several stages of grouting, no progress is observed, it may be necessary to move to another area. This could indicate an anomaly or unidentified voids. The key takeaway here is that the right answer is never to pump more grout when in doubt. The process should be slow, methodical, and thoughtful to ensure impact.

With technical expertise and reliability, the methodical approach of stage grouting emphasizes the importance of patience and careful monitoring in achieving optimal results. Remember, when it comes to grouting, the goal is not to use more material, but to use the material more effectively. Go slow, be methodical, think about it, and make sure you're having an impact.

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Restoration waterproofing is always a unique undertaking as there are many unknowns. Identifying the source of the infiltration is the obvious first step and it is a challenging one. Properly diagnosing a leak may require numerous steps that include, but are not limited to, inspection, flood testing, dye testing, mock-ups, removal of finishes, and occasionally destructive test methods.

Setting Clear Goals

Before embarking on a restoration waterproofing project, it is important to set clear goals and expectations for all parties involved. Clearly, stopping water intrusion is normally the main goal. Various methodologies and products can be employed to achieve this goal. Each of those may have different costs, varying levels of site disruption, and varying timetables. These should all be discussed so the end customer can make a well-educated decision.

Understanding Water Migration

It is important to understand a few key concepts about water migration. Just because a leak only manifests in specific areas does not mean that there are no other locations allowing water ingress. Water seeks the path of least resistance, typically the low spots. As these low spots are remediated, the water may migrate to other failed areas. This can be further complicated if the repairs are conducted during a relatively dry time, as the leak migration may not manifest until the next rain event. Conducting waterproofing repairs during active leaking helps to identify leak migration issues. Flood testing before, during, and/or after the work also can help identify leak migration.

In summation, remedial waterproofing is often an explorative process and can require on-the-fly adjustments. Setting expectations, maintaining open communication with all involved parties, and attention to detail are essential to making the waterproofing process efficient and successful.

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Alchatek offers a series of short educational videos covering a variety of polyurethane concrete repair applications. Each video is described below, followed by a viewing link.

Slab Lifting with Polyurethane Foam

This live-action video depicts a typical residential driveway slab lifting job, including a simple overview of the causes of settled slabs, the alternatives to polyurethane slab lifting, and the polyurethane slab lifting process itself. The slab lifting sequence features added 3D animation to show the foam expansion process underground during the slab lifting process. Click here to watch the video.

The Polyurethane Slab Lift Process Explained

This animated video explains the polyurethane slab lift process in detail, primarily in the context of commercial/industrial applications. Sunken concrete slabs can be lifted back into place with two-component polymer foam designed to work in wet or dry conditions. The expansion force of the concrete leveling foam coupled with the pressure of a specialized pump generate enough controlled force to lift virtually any structure back into position with 1/8” precision.  Click here to watch the video.

The Polyurethane Soil Stabilization Process Explained

This animated video explains the most common infrastructure and concrete issues requiring polyurethane soil stabilization, as well as the application process itself. Unstable, eroded, or loose soil around infrastructure can result in settlement and damage to the structure. Voids can be filled, soil consolidated, and water migration halted by permeating the soil with one of the AP Soil series of polyurethane resins. Click here to watch the video.

The Deep Lock® Process Explained

This animated video explains deep soil stabilization in great detail. Alchatek offers a unique combination of high-quality structural polymers along with the equipment and training needed to address deep soil issues. Contractors trained in The Deep Lock® process can stabilize soil at all levels and accomplish this with minimal imposition to or downtime for the property owner. Click here to watch the video.

The Polyurethane Leak Seal Process Explained

This animated video explains the most common infrastructure and concrete issues requiring polyurethane leak seal solutions, as well as the various application processes. Leaking concrete can be detrimental to safety and property values. Leaks in concrete structures can be permanently repaired with water-activated polyurethane and a few assorted leak seal accessories. Click here to watch the video.

Alchatek - A Supplier You Can Trust

This video provides a quick overview of Alchatek, an international leader in the manufacture and supply of chemical grouts and construction products for Geotechnical, Leak Seal, and Seawall Repair applications. Providing solutions from its headquarters in Tucker, Georgia, and its manufacturing facility in Reno, Nevada, Alchatek specializes in advanced construction technologies for sealing leaks, stabilizing soils, lifting concrete, and protecting infrastructure and seawall structures. Click here to watch the video.

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So, you have another clog in your boot? Well, your grain elevator boot that is. This means shutting down to clean your grain elevator. Which means loss of production, loss of grain, and delays. Drains and sump pumps clog and can be unreliable. 

A grain cooperative in Washington state contacted Kodiak Concrete Lifting. Alchemy-Spetec's Leak Seal Division Director of Technical Services, Charlie "The Grout Geek" Lerman, met Kodiak on-site and inspected the leaking boots in question. One was poured concrete and the other was poured concrete with a metal interior liner. Both had multiple areas of water intrusion and sumps that were not able to handle the leakage. Charlie worked with Kodiak on developing a grouting plan and an estimate for the co-op.

Powerful Polymer

Spetec PUR HighFoamer was the ideal grout for forming a positive side waterproof barrier known as a curtain wall without having to excavate and with very little downtime.

Spetec PUR HighFoamer is a highly expansive grout (40x-50x) and it is also NSF 61-approved for potable water use.

Painless Procedure

Pumping polyurethane grouts is done with a modified airless paint sprayer. Since this pump is lightweight, it is easy to mobilize in remote or difficult-to-access locations. Normally, the technicians would set up a 2’ on-center grid pattern for curtain wall grouting. With the elevator equipment layout, they had to adjust the spacing. By pumping hole to hole they ensured water-tight grout coverage even with the irregular port spacing.

Rapid Result

A few weeks later, Charlie Lerman and Kodiak met back on-site for the installation. While working in a grain elevator pit and working with urethanes can be a bit messy, the injections went well and the water intrusions were stopped in both pits on time and under budget.

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A major culvert restoration project was recently completed by Geotech Services Inc. in Ohio. The Este Ave culvert is a concrete storm sewer that runs about 1000 feet from 4861 Este Ave to Mill Creek. The culvert includes 200 pipe joints, the majority of which are not watertight, and is 108 inches in diameter. A few of the sealed joints in the culvert have failed, leading to enhanced infiltration at downstream joints. The groundwater infiltration ranges from modest seepage to major leaks. Although there aren't any voids easily seen at the surface, it's expected that some channeling has happened along the pipe's bottom. In 2008, grout was injected to seal several joints near the intake and to fill voids around the outside of the pipe. Controlled density fill was then used to fill voids at the surface around the wing wall. Since that time, the wing wall has remained stable. Unfortunately, the culvert's sealed joints have degraded, leading to more infiltration at downstream junctions.

Powerful Polymer

Geotech Services used Spetec PUR GT500 to seal all the pipe joints in the culvert and to fill voids around the outside of the structure. Spetec PUR GT500 is NSF/ANSI 61 approved for contact with drinking water. This single-component polyurethane resin is designed to penetrate and seal off leaks in cracks, joints, and pipe penetrations. As a hydrophilic polyurethane, it chases down water and gets into the microstructure of the concrete, forming a flexible seal and a mechanical bond with the wet concrete.

Painless Procedure

Every joint in the culvert's bottom half was leaking and allowing groundwater to seep in. Geotech Services drilled one injection hole in the middle of the culvert joint at the bottom and injected the GT500 until the joint was completely sealed. Additional holes were drilled, based on how the material was traveling. About 3500 gallons were injected overall.

Rapid Result

The entire 1000-foot culvert was sealed in just under 30 days.

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Premier On-The-Job Technical Support

Alchemy-Spetec offers onsite training for qualified geotech and leak seal customers. Starting up a contracting business, tackling a larger job than you're used to, getting new personnel trained, or adding a new service to your arsenal can be daunting. Our industry-leading technical support team specializes in training contractors on the job site. 

Always Be Prepared for Lucrative Jobs

With the backing of Alchemy-Spetec's technical support team, you'll never have to worry about your crew's ability to take on the next opportunity - whether it be a first-time geotech or leak seal job, or a bigger job than they are used to. Qualified customers can schedule an onsite visit from an Alchemy-Spetec specialist in order to ensure that the process goes as planned.

Estimation and Job Planning Assistance

Speaking of planning, your technical support specialist can also work with you in the estimation and preparation stages of your project as well.

Call 404-618-0438 for more information on Alchemy-Spetec technical support.

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A homeowner in Alaska reached out to contractor Ace Dragon about leaks in their basement. The basement was built with insulated concrete form walls that are typically installed in colder climates. Despite being an excellent solution, problems can arise if not installed properly during construction and the home was suffering from leaks due to poorly consolidated concrete within the walls. During construction, these specially designed walls provide insulation with concrete filling the hollow cavities. However, whenever concrete is poured it requires vibration to ensure it is properly consolidated. The walls in this home did not contain properly consolidated concrete and thus were leaking.

Powerful Polymer

After conducting a thorough inspection, the crew from Ace Dragon found issues with the membrane around the perimeter of the house and proposed injecting Alchemy-Spetec’s Spetec PUR Highfoamer into the walls to make up for the weakly consolidated concrete and seal the leaks. This durable polyurethane was perfect for this job due to its low cost and high expansion rate.

Painless Procedure

The job only required a small three-man crew and some light equipment. Starting their injection procedure from the bottom, the crew worked all the way around and up the entire basement wall to ensure all affected areas were sealed. The homeowner’s only other effective alternative would have been to excavate around the entire perimeter of the home and completely redo the membrane (something they wanted to avoid due to the high costs).

Rapid Result

The injection process took a fraction of the time a full membrane replacement would have taken. The homeowner was thrilled to have the leaks sealed and the basement walls fortified.

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A property owner reached out to a geotech contractor for help with a leaking retention pond. The pond feeds into a creek via a concrete spillway. Over the years water has worked its way through the earthen dam and under the spillway, causing large voids and soil loss under the concrete.

Powerful Polymer

The technicians selected AP Fill 720 as the repair material for this job. AP Fill 720 is a single-component, closed-cell, hydrophobic, water-reactive, phthalate-free, low-viscosity polyurethane injection resin for cutting off large water leaks and filling voids around structures. This high-strength durable material will react and expand quickly upon contact with water and is one of the top soil stabilizers on the market. 

Painless Procedure

The spillway was about 15 x 15 feet in size, with one 15-foot side bordering the pond. After soil probe testing it was decided that the crew would inject AP Fill 720 directly next to the spillway on the pond side and then directly underneath the spillway via 5/8 inch drill holes in the concrete along the border with the pond. All injections were completed to a depth of four to five feet.

Rapid Result

This project was completed within a day. The AP Fill 720 structural polymer was cured within a couple of hours after injection. The homeowners were thrilled to see their pond system, which they were heavily invested in, finally functioning as it was designed.

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It's that time of year again. As temperatures drop, take a moment to review this previously posted article packed with cold-weather tips.

There are plenty of leak seal jobs that need to be done in the winter. So let's take a look at those cold-weather markets. We'll also review some special considerations for conditioning leak seal material and equipment. Then we’ll leave you with a few cold temperature leak seal application tips.

Cold Weather Markets

You have a variety of options for seeking jobs that are inside, and out of the elements, during the winter months.  Hopefully, these ideas will spark more brainstorming on your part. First up we have tunnels, both pedestrian and vehicle. Tunnels often leak, sometimes significantly enough to result in quite a big job. Aquariums are another possibility. As you can imagine, there are infinite potential leak problems in a structure holding that much water. Other possible large jobs could include mines and water treatment plants (which have plenty of interior spaces with potential leak issues). On the smaller side, there are utility vaults, lift stations, manholes, and elevator pits.

If you’re still up for working outside during the winter months, you’re in luck because concrete contracts during colder weather. The contraction makes cracks open wider. Wider cracks make leaks more apparent to the property owner and make them easier to repair.

Conditioning Materials and Equipment

One important point to understand is that cold weather requires you to make an extra effort to keep your materials and equipment warm. Cold material reacts slower and gets thicker. Be sure to store your materials and equipment in a heated room the night before the job. When on the job site, there are many ways to keep everything warm. Use an enclosed vehicle, like a box truck, enclosed trailer, or pickup truck with a camper top or bed cover. Keep as much material and equipment inside the vehicle as possible when working. Use a portable heater to maintain a warm temperature. You can also use electric pail heaters to keep your resin ready for action.

Remember that it won’t do you any good to heat the resin if you’re pumping it through cold equipment. The cold steel inside the pump and the cold hose will literally suck the heat out of the resin before it gets where it needs to be. This will increase the viscosity, making it harder to mix with the water and it will slow down the reaction dramatically. So don’t neglect the equipment side of the equation!

Cold Temperature Application Tips

If you’re using a product with an accelerator, you may need to use a faster accelerator or increase your percentage. Also, bring lots of oakum. You may have to use more if the cold temperature slows down the material or the contracted concrete has made the cracks wider.

If your job requires you to inject into a structure underwater (and the water’s cold), you can use a technique called twin streaming. In this approach, you hook two valves together in a parallel fashion – then inject warm water along with the resin to kick-start its reaction before hitting the cold water.

Conclusion

I hope this overview has helped spark some ideas on your part for finding leak seal work during the winter months. Just remember to keep your materials and equipment conditioned and you should be fine. Have more questions about polyurethane leak seal in cold weather? Call us at 404-618-0438.

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Back in the 1990s, the Seaholm Power Plan in the City of Austin, TX closed after four decades of operation. Recently, the entire area has been converted into an indoor-outdoor park and public space called the Seaholm Waterfront. All that's left standing of the original power plant is an intake building that the city decided to repurpose for public use as part of the project. Thirty feet below grade, are chambers that were originally designed to hold water from the river and pump it into the power plant to cool the machinery. The intake building renovation project hit a snag when they discovered that several thousand gallons of water were pouring into the chambers on a daily basis.

"Sealing of the intake gates was necessary in order to eliminate water from being continuously present within the building. Nine of the 10 wells have been successfully sealed off. While pumping the water out of the building, leaks were discovered in one of the wells which will require additional work by the underwater construction crew. Preventing the free-flowing entry of lake water into the building is central to the scope of this project improving the occupancy conditions by lowering humidity levels, eliminating odors and pests, and preserving the integrity of the building materials."
— Austin City Council, April 21, 2021

Initially, concrete was poured into the chambers to stop the leak. This proved to be ineffective and further complicated the job. Specialty contractors Canalco were brought in to seal the leaks via polyurethane curtain grouting, in which the technicians drill holes through concrete and inject water-activated grout on the other side, stopping the leak at its source. Technical assistance was provided by Chamberlin Waterproofing.

Powerful Polymer

The engineering firm Wiss, Janney, Elstner Associates, Inc., specified Spetec PUR HighFoamer as the best grout to handle these high-pressure leaks. Technicians can easily adjust the set time for this material. They can speed it up for gushing leaks and slow it down to maximize coverage and penetration into the substrate for curtain grouting.

Painless Procedure

A small crew sent a confined entry certified technician deep into the well to drill 1.25" injection holes 4-7' feet through the concrete. Next, he injected Spetec PUR HighFoamer through five holes to create a grout curtain on the outside of the structure to seal off the leaks.

Rapid Result

The job was completed in just one week. The city continues to monitor the situation and the results have been spectacular given the difficulty of the job and the complications.

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