The Crack Injection Process

Crack injection is a precision-focused leak seal approach for smaller cracks or joints. Contractors repair these defects by drilling holes into the wall and inserting injection ports at an angle to intersect the crack inside the wall. Next, they inject polyurethane grout directly into the center of the crack through the ports. The resin rapidly reacts with water to form a flexible watertight seal. 

This process also protects the rebar inside the wall. Water intrusion through the cracks can lead to rebar corrosion and concrete spalling. Rusting rebar can expand six to ten times the original volume of the steel. This creates internal pressure on the concrete. While concrete is very strong in compression, it has a low tensile strength, and the expanding rebar will cause it to crack. When polyurethane resin is injected under pressure, it can encapsulate rebar and slow down the corrosion process.

Crack Injection Case Studies

• Water Treatment Plant Losing Two Million Gallons Per Day Due to Leaks
• Sealing Leaks in a Church Wall to Stop Costly Flooding of Elevator Pit
• Saving a Luxury Penthouse Suite from Costly Water Damage (Just in Time!)
• Leaks in Wastewater Treatment Plant Sealed to Prevent Environmental Contamination
• Contractor Seals Leaks in Quenching Tanks for Aluminum Manufacturer
• Leak Seal in Water Treatment Plant Pump Station Manhole
• Specialty Waterproofing at Hydroelectric Dam
• Sealing Hairline Concrete Cracks with Acrylic Injection Resin

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The Curtain Grouting Process

There are negative-side leak seal solutions, in which contractors apply surface treatments to the face of a wall to stop leaks. However, this is merely a band-aid approach. The water pressure coming through the cracks from behind the wall can still blow this band-aid repair right off. Contractors using positive-side solutions like curtain grouting can stop multiple leaks in a structure at one time.

In this process, holes are drilled through a structure in a diamond pattern. Next, expansive leak seal grout is injected through the structure, sealing leaks and filling soil voids on the other side. The grout quickly reacts with the water and cures to form a curtain wall made of a resin/soil mixture that seals the leak permanently. This is a positive-side waterproofing solution applied from the negative side.

Curtain Grouting Case Studies

• Massive Underground Leak in Aquifer Shut Down
• Protecting Drinking Water from Potential Flood Contamination
• Repairing a Leaky Pipe & Sinkhole on a Residential Property

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Alchemy-Spetec offers one-hour CE/PDH accredited presentations on polyurethane concrete repair. Presentation topics offered include Leak Seal, Geotech, and Seawall Repair. Here is a detailed overview... 

Leak Seal Presentation

The Specialty Waterproofing with Chemical Grouts presentation covers sealing leaks in structures with the use of polyurethane chemical grout injection materials and techniques. 

• Chemical Grouting Primer
  • History
  • Safety
  • Characteristics
• Utilization & Applications
  • Identifying Applications
  • Selecting a Chemical Grout
  • Epoxy & Hydraulic Cement
• Installation Techniques
  • Crack and Joint Injection
  • Curtain Grouting
  • Oakum Soakum
  • Equipment Overview

Alchemy-Spetec's one-hour CE/PDH accredited Leak Seal presentation is perfect for engineers looking for information on innovative and proven leak seal repair methods for sealing leaks in structures, inflow/infiltration mitigation, and more.

Geotech Presentation

The Geotechnical Applications for Polyurethane presentation explains three types of concrete leveling and soil stabilization materials and applications. 

• Single Component Polyurethane Grout Applications
• Two-Component Polyurethane Grout Applications
• Acrylic Grout Applications

Alchemy-Spetec's one-hour CE/PDH accredited Geotech presentation is perfect for engineers looking for information on innovative and proven geotechnical repair methods for lifting concrete, soil stabilization, excavation support, controlling erosion, and more. 

Seawall Repair Network Presentation

The Seawall Stabilization and Preservation through Permeation Presentation explains and demonstrates how Seawall Repair Network contractors use polyurethane injection resin and surface-applied preservation solutions to stabilize and preserve seawalls and bulkheads. (Seawall Repair Network is a division of Alchemy-Spetec.)

• The Causes of Seawall Failure
• Stabilizing a Seawall
• Preserving a Seawall
• Stabilization & Preservation Through Permeation

Alchemy-Spetec's one-hour CE/PDH accredited Seawall Repair Network presentation is ideal for engineers who are interested in designing superior seawall/bulkhead rehabilitation and preservation solutions. This type of environmentally friendly permanent soil stabilization and seawall preservation can be applied to all types of waterfront infrastructure.

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The John Day Dam is located in the state of Oregon on the Columbia River. In 2020 the Army Corps of Engineers put a repair job out to bid to address a variety of situations, including leaks that were occurring in a number of the galleries (openings or passageways within the dam). The general contractor that won the bid brought Spokane, Washington’s Talisman Construction Services in for the leak seal portion of the job.

Powerful Polymers

The Army Corp of Engineers specified a flexible polyurethane for the specialty waterproofing due to the fact that it would be injected into dynamic joints and cracks (joints and cracks that contract and expand with weather conditions).

The technicians from Talisman Construction Services chose Spetec PUR F400 from Alchemy-Spetec. This product features 100% elongation. If you install a rigid product in a dynamic joint or crack is will fail at the first movement. In addition to its flexible nature, Spetec PUR F400 is also hydrophobic. Hydrophobic polyurethanes have excellent chemical resistance and superior longevity. In addition, Spetec F400 features a field adjustable set time (when you have cold water, with varying volumes, this is essential so you can either penetrate small cracks with a slower set time or shut down gushing leaks with a faster set time).

The Bureau of Reclamation and the Army Corp of Engineers have approved Spetec PUR F400 for use on their structures. This durable repair material has been successfully installed in many of their dams and locks.

Painless Procedures

One of the classic rules of grouting cracks and joints is to pull off the crack or joint half the thickness of the wall and drill at a 45° angle. However, when you get over 3’ thick it is not necessary to pull off the crack or joint more than 1.5’. The crew followed these guidelines when injecting the resin.

On thicker structures leaking cold water at high volumes, it is imperative to be able to adjust the set times in the field. Gen ACC is the accelerator for Spetec PUR F400 and is added at a ratio of 1% all the way up to 10%. The more you add the quicker the product polymerizes. The crew adjusted the set times according to properties of each leak.

They also soaked AP Oakum in Spetec PUR F400, and packed it into the wider cracks and high volume leaks. Depending on the situation, the oakum is sometimes packed in before the injection or packed in simultaneously as a second crew member fills the void with the first crew member is injecting the resin.

Rapid Results

Within a matter of days, the leaks in the galleries were successfully remediated. The general contractor was then able to move on to other parts of their project, on budget and on schedule.

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This article is an excerpt from Episode 14 of Alchemy-Spetec's podcast The Injection Connection, featuring veteran coatings expert Murray Heywood. (If you'd rather view or listen, an audio/visual version of this excerpt is posted at the bottom of the article.)

Charlie Lerman: When I’m training people that have never done grouting before, the ones that I find that are the easiest, honestly, are people who do coatings. The reason is that they're already handling paint equipment and chemicals. When you talk to some contractors they say, "Oh, my God, I got to buy an airless paint sprayer? Can't I just use a caulk gun or something?" And when you're starting off at that level, you could use cartridges and a caulk gun, but it's like showing up to do brain surgery and you've got a drill, a hammer, and a kitchen knife. It's not the right way to start off.

We did a webinar with about 50 Sherwin-Williams people. We got a number of good opportunities out of that, but one of the best ones was a flooring guy who just happened to be on there. One of your flooring guys. He got one of his coating guys involved, and he is now a regular grout user. And they don't go chasing the jobs, they just do it all internally when they run into situations. They now say, "This is going to be a problem for our coating. We know it, we're going to go ahead and grout that ourselves beforehand." And that to me is wonderful.

Murray Heywood: One of the biggest problems with flooring - flooring's a nightmare. There are a lot of coating failures on floors and a lot of it has to do with moisture. Because where is that moisture traveling from underneath the slab? It's coming through, it's chasing the heat. It's coming up through, and anything you put over the top without addressing that - it's blistering and causing issues. That's one of the things that was top of mind for me. It wasn't my division, it wasn't my responsibility, but I always thought the flooring people needed to know about this. Because water is a big problem for them.

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This post is part of the Alchemy-Spetec Contractor Lens series, featuring views, news & case studies written by our customers. This article, written by John Knieper of SiteMix Pressure Grouting LLC, provides an overview of a retention pond repair job. If you're an Alchemy-Spetec customer and you'd like to discuss writing content for our blog, please send an email to marketing@alchemy-spetec.com today!

A property management company in metro Atlanta contacted SiteMix Pressure Grouting, LLC to address an issue with a neighborhood retention pond that was not holding water at the proper level. The customer reported that the water level was not running through the top of the concrete outlet control structure as designed but water was exiting on the other side of the earthen dam through the concrete outlet pipe. Upon inspection, it was discovered that the pond water was piping along the outside of the concrete outlet pipe and leaking back into the outflow pipe through several bad joints in the concrete pipe.

Powerful Polymers

The SiteMix Pressure Grouting crew choose AP Fill 700, a single component, water-activated, hydrophobic, low viscosity, closed-cell polyurethane injection resin for the repair. Specifically, AP Fill 700 is NSF-approved for contact with drinking water, safe for the environment and allows the crew the ability to adjust the catalyst for set time. The polyurethane material is ideal for permeating soil, filling voids and water cutoff.

Painless Procedures

AP Fill 700 was injected on 18-inch centers around the base of the OCS and outlet pipe in order to inject resin into the flow of the piping water. Specifically, the set time of the resin was reduced so that the piping water would take the resin the length of the pipe to the leaking joints. The goal was to have the AP Fill 700 react from downstream back up to the OCS. Crew members observed the pipe joints until AP Fill 700 presented and all the leaks stopped.

Rapid Results

The job took one day to complete and less than 50 gallons of resin. Within three days the pond was at full pool and the management company and neighborhood residents were very satisfied with the work.

Want more information on geotech products?

This article is an excerpt from Episode 14 of Alchemy-Spetec's podcast The Injection Connection, featuring veteran coatings expert Murray Heywood. (If you'd rather view or listen, an audio/visual version of this excerpt is posted at the bottom of the article.)

Charlie Lerman: I’ve been on the services side for close to 18 years now. So I’m a big proponent of training and providing service. I'd like to acknowledge one of the other manufacturers out there that provides great training. Sherwin-Williams seems like a champion of education. They've got a great technical service group. I wanted to get your opinion on the value of bringing contractors to the trough, to drink, to understand, to learn...things like that.

Murray Heywood: Yeah.

Charlie: I don't even know if that was a question, more of a statement.

Murray: Well, that was one of the things that was unique to our group at Sherwin-Williams. Kevin Morris and I saw Sherwin-Williams as a sales organization. They manufacture paint to sell it. They aren't necessarily a technical organization. But I always believed that the more educated the sales reps are, the more they're going to be able to sell. Because if you don't know as much about something as the person you're trying to sell it to, you're going to have very limited results. But if you can at least talk the talk and walk the walk, and understand what you're talking about, then you're going to be more successful. And you're going to be able to help your customers, which builds a sense of loyalty.

If you solve a problem for somebody, they don't readily forget you. That's how I built my whole career as a rep: help people out, solve problems for them, and they will always come back for more...always. It's very rare that you save somebody some money and get them out of a jam and they say, "Well, I’m going to lose his number." That's not the way it works. So I think that Kevin and I decided early on to always ask ourselves, "How can we make it better? How can we make our people smarter and more equipped to sell?" And it's a whole package because you're selling coatings but we know the number one enemy of coatings is water. They sort of go hand in hand.

So I think that, while running these training sessions for contractors was great and everything, I saw that educating our own people is almost more important. That way our people can go out and help these guys. The training sessions we did were very successful. This has been a pet peeve of mine with every sales organization I’ve worked with in the paint world - you can't just find another one. It's not like selling shoes or widgets. There's a technical aspect to coating sales, especially on the industrial side. And the more you educate your salespeople, the better they're going to be. You're also reducing your own risk at the same time by doing things right.

We just talked about the cause of failure being ignorance and indifference. Indifference to quality, ignorance of quality. My old man, for example, thought he did good work. He just thought everybody else was too fussy. His attitude was, "Oh, it'll be fine." And I was a young guy who was saying, "No, I don't think that's right, Dad. I think that's a horrible plan." My dad never used his blinkers while driving and it used to infuriate me. I’d say, "Dad, you've got to use your blinkers, man." He'd reply, "Listen to me, smart guy, I’ve been driving for years and I’ve never had an accident." And I would think, "Yeah, well, you've left a trail of destruction behind you. You just don't know what you don't know."

And that's kind of like contractors who think they're doing well, but they don't realize that what they're missing is creating a whole backlog of problems. So all this training needs to happen with coating manufacturers. I mean, what could you possibly lose by being smarter about your products? Why not? As  sales organizations, and I can speak candidly about this now because I don't work for them anymore, we spent so much time on sending people to this or that random training or some feel-good training. All that kind of stuff that doesn't move the needle at all. It's just so somebody can check off a box and say, "Yep, we accomplished that."

It was always more difficult when we tried to push them through real technical training because you don't do it in one afternoon. We used to run our boot camps if you remember, and they were intense weeks of training. We were getting things in people's hands, getting a grout gun in their hands, and hooking that nozzle up to the zerk and pumping it. That kind of stuff. Hands-on. That's how I learn. I learn by doing, and so I think the more that you can convince these coating manufacturers to accept this kind of training and to invest in it, the better. Because if you think about it, we know that we haven't even scratched the surface of the biggest opportunities in waterproofing and grouting. We're usually dealing with the obvious things. But there's the stuff that's not obvious that it also can fix - and that is the biggest opportunity.

View the video version of this excerpt...

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This article is an excerpt from Episode 14 of Alchemy-Spetec's podcast The Injection Connection, featuring veteran coatings expert Murray Heywood. (If you'd rather view or listen, an audio/visual version of this excerpt is posted at the bottom of the article.)

Charlie Lerman: One of the things I say and again - and I’ll bounce this off you since you're from the coating side - I always contrast our grouts to coatings because with coatings, you can see them, you can touch them, you can do all kinds of tests. And I also always say it behooves us to train our contractors well and support them to get the products installed correctly because it's not like a coating. When you're a coating manufacturer, if there's a problem with your coating, you come out there, you do a pull test, you do a spark test, you can check the millage of it, you can say the surface prep was wrong and you could say, "You know what, you didn't follow the right installation procedures." With grouting, I’d come out and say the same thing that the contractor didn't follow the correct procedures, but what are we going to do? Cut the wall out? Dig up the whole thing in downtown and show? We can't prove any of that. It's very important. Grouting gets a black eye when it's not installed right because we can't test all those things. And I think that's one of the reasons that grouting has always stayed kind of small is because there are no really great, quantifiable, repeatable engineering tests that work everywhere to test grouting.

Murray Heywood: No, it really comes down to, did the water stop, right?

Charlie: Yes.

Murray: And if the water doesn't stop, that doesn't necessarily mean that there was something wrong with the grout. It's often that the problem was bigger than you thought because you can't see it. You're doing educated guesses. As a grout geek you know, "Well, I’ve seen this before. I know that we're going to have to put a port here and we're going to chase it around here." You can make some educated guesses but you're right. I can go in with the coating and with my gauges and test the DFT and quickly say, "Well, your spec said you're supposed to have 40 mils on here. You've got 20. So you're half of what you should be. Shame on you." Or I can pull the coating off and say, "Well, you have no surface profile, you didn't prepare it." And I’m sure the skeptics are thinking, "Oh, yeah, well, you're just saying that to cover your own butt." It’s virtually unprovable other than, when the water didn't stop it's obviously not working. And they say, "Well, your grout’s no good." I do a lot of failure analysis and failure investigations. That's the majority of what I do now is failure analysis. And I like that, it's kind of like CSI Paint. And I enjoy that. But still to this day, 100 years into this coating thing, the biggest cause of failure is poor application, poor surface preparation, and poor environmental conditions during the application. It always relates, 98% of the time, back to something that didn't go right with the application. And that can be the same with grouting. If you don't know how the water's flowing or if you can't make some educated guesses on how the water's getting in, you don't know where to start. And sometimes, as you know, you could be pumping grout in one side and it's coming out the other side and not doing anything.

Charlie: It always goes somewhere. It's about how we get it to go where we want it to through a foot of concrete. How do we control a liquid? That's what it comes down to.

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In the city limits of Atlanta, a couple was surprised to see a sinkhole forming in their home’s front yard. They became quite alarmed as within just a few weeks it swallowed their sidewalk and a decent portion of the property in front of the home. They notified the city. 

After the City of Atlanta quickly got involved, some investigation revealed an old brick storm sewer running approximately 25-30 feet under the front of the property. Across the country, there is lots of brick infrastructure that’s still in service and in some cases over 100 years old. These outdated structures suffer from infiltration of groundwater which often erodes soil, as well as causes subsidence above. In this case, cameras revealed that several bricks had become dislodged, creating a pathway for soil and groundwater to get in. The end result was a rapidly forming sinkhole.

The City of Atlanta was already consulting with Alchemy Spetec on some other projects, so they asked us to take a look. After reviewing the available information and making a site visit, it was determined that a multi-step plan would need to be undertaken to seal the pipe and reestablish soil compaction.

Powerful Polymers

The single-component polyurethane AP Fill 700 was selected for the sealing of the pipe and for the compaction grouting of the above soils. AP Lift 430 would be kept on standby in case further grouting was required to stabilize under the home foundation itself. As it turns out, this was indeed the case.

• AP Fill 700 has an adjustable set time and is highly expansive. It works in wet environments, perfect for this project. It can permeate loose soils and gravel and achieve compressive strengths in excess of 1000 psi.
• AP Lift 430 is fast and expands 24 times its original volume. It is strong and can support 7,000 lbs per square foot.
• Both products are NSF ANSI 61 approved as safe for potable water contact. This certification provides reassurance that these products will not leach any chemicals out into the soil.

Painless Procedures

As previously mentioned, there were several steps that had to be undertaken to complete this project. First, the bricks that had become dislodged were reaffixed back into place. Once that breach was sealed, AP Fill 700 was injected through the pipe walls in multiple areas around the breach. AP Fill 700 reacts when it contacts moisture and there was no lack of that at 25 feet deep. Regardless, twin streaming through an F-Valve Assembly was implemented to ensure a good resin/water mix. This approach rapidly filled all of the voids surrounding the pipe and also sealed several other small areas of weeping water infiltration.

The second step was to fill the sinkhole with loose dirt and gravel and then permeate that with AP Fill 700 to squeeze the soil and lock all of the backfill together. Half-inch injection pipes were installed down to the top of the pipe, then soil and gravel were backfilled to the surface. Once the backfill was in place, AP Fill 700 was injected and the probes were slowly extracted to insure a uniform measure of polymer throughout the soil column. When this is done in a grid pattern, the result is a lot of increased compaction and bearing capacity.

Once the sinkhole was repaired, concern remained about loss of soil compaction under the foundation of the home. The steps leading up to the front porch had settled away from the home indicating further bad soil was likely the case.

Alchemy-Spetec is a dealer for Pagani, a dynamic cone penetrometer (DCP) manufacturer out of Italy. We brought our unit out to the property and did 6 penetrometer tests across the front of the home next to the foundation. Four of the six tests revealed weight of hammer (WOH) readings which basically means zero compaction. The soil could not even support the weight of our machine. The city was on site to see the tests and immediately approved the compaction grouting beneath the front foundation. This is where the AP Lift 430 came into play.

Half-inch injection probes were installed across the entire front of the home next to the foundation. Probes were installed down to 8 feet which is where the soil became much stronger. AP Lift 430 was injected while the crew slowly extracted the probes - until lift was observed on the home. When lift was detected, the grouting ceased. This process was repeated across the entire front of the home on 4-foot spacing.

After the compaction under the footing was reestablished, the front steps that had settled away from the house were lifted back into place using AP Fill 430.

Rapid Results

The job was completed quickly without any excavation and dewatering. No curbs, road base, or utilities had to be removed or relocated. This approach saved enormous amounts of additional cost and delays.

Want more information on leak seal and geotech products?

This article is an excerpt from Episode 14 of Alchemy-Spetec's podcast The Injection Connection, featuring veteran coatings expert Murray Heywood. (If you'd rather view or listen, an audio/visual version of this excerpt is posted at the bottom of the article.)

Charlie Lerman: Now what would you say is maybe the most interesting job that you've been on - or unique or weird - or something that just stands out in your head (with grouting obviously)?

Murray Heywood: Well, I should have been more prepared for that question because I’ve been on so many projects. But one of the things that struck me a few years ago was at a water treatment plant in New Jersey. I was in the pipe gallery. You've got to remember, in the pipe gallery you have tanks on either side of you, and possibly tanks above you - all filled with water - none of which are lined. They're all just bare concrete. I’m walking through this because we're there to look at the pipe. They've got all this corroding pipe and they're kind of perplexed. These pipes are severely corroding, with all these issues and I’m walking through this huge pipe gallery. It's huge, it's long and wide and they're worried about their pipe. And meanwhile, there's water spraying and dripping and coming out of every pipe penetration and crack. It's like a rainforest in there basically. Have you ever been to Niagara Falls and been behind the falls?

Charlie: I haven’t, but my wife has.

Murray: Yeah, you can go behind the falls. It's kind of like that. And there's water coming out from everywhere. I say, "We can address the corrosion and take it off and repair it and do all that stuff, but you've got to fix this leak." They look at me and say, "Well, it's a water treatment plant." I reply, "Yeah, but this doesn't have to happen. This is not normal. This is not just part of the normal day that you just let water spew in and all over the place and expect to have good results." So I made a recommendation.

Charlie: Yeah.

Murray: And I think they actually addressed all of that in there, but I was just struck by how oblivious to it they were. There was so much water coming in. And then there was another situation here in Canada at a plant north of here. They had another situation where they had a tank on one side and a pipe gallery on another. Now in the previous example from New Jersey, the pipe gallery wasn't painted, the walls weren't painted, it was just a concrete room. In this one, they kind of wanted to dress it up, so they kept painting these walls. And every time they'd paint the walls, all these leaks were happening and the paint would come off. They must have to put like 40 coats of paint on this thing. Then I walk in one day and I say - because the paint was now at this point with all the peeling - "Yeah, this is always a problem. Well, it's not the paint that's a problem. It's the fact that you've got all this water coming out all over the place." And they reply, "Well, we've tried to stop it but we don't know how." So I gave them some instructions on how to do it. They got somebody in, I don't know who, and they fixed it. I’ve talked to them since then and they haven't had any further issues. So it's just that. As I said, it's the lack of education that there's a fix out there. And let's be honest, it's not rocket science, it's a relatively simple fix.

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