Alchatek Blog

Hopefully these tips on overcoming obstacles on remote job sites will be of assistance on your next out-of-the-way project. At one point I had the opportunity to advise a customer who was repairing pipe penetrations of aerial manholes along a drainage basin in SW Atlanta. Aerial manholes are typically found in low spots next to creeks and rivers. They are usually connected by steel or ductile iron sewer pipes that are above ground and thus, so are the penetrations.

The conditions of the job site were unique as there was no access to the individual manholes except by foot. This particular project covered a winding 1-1/2 miles through ravines and involved several crossings of the stream. The goal was to seal the 18” and 22” pipe penetrations that were leaking raw sewage down the faces of the manholes located along the creek. In this report I will let you know how we got started in preparation for the unique set of challenges this project presented.

First of all, a thorough evaluation of a remote job site must be undertaken. This should be done prior to submitting a bid, but it should also be done again with an extra set of eyes prior to commencing the work. Then create a plan and a master list of what you will need:

1. Consider all of the possibilities of how to mobilize; where can you set up the nearest base camp for your trucks and supplies.
2. What tools or alternative tools can be used to get the job done; realize there are certain conveniences you're not going to have, like generators and air compressors, and find alternative methods.
3. Select the right Leak Seal materials to get the job done such as AP Seal 500, AP Fill 700 and activated oakum.
4. Prepare a good safety plan. We experienced rugged terrain, snakes, bees, ticks, extreme heat, downpours, and lightning. Think about how to protect your people, your materials, and your gear. Make sure to have first aid and hydration available on site and at the base camp.
5. Have a communication plan – make sure you have reception between the job site and the base camp. If cell phones don't work then bring walkie talkies. Have someone at the base camp to watch gear, to get supplies when necessary, and to be available for help in case of an emergency.
6. Be prepared to clean up your job site with respect for the environment. If you haul it in, be ready to haul it out.
7. Last of all, choose the right people for your crew. Think carefully, because these kinds of jobs are not for timid or easily discouraged personality types.

In my next post I will go into detail on the procedures and tools we used to stop the leaks through a combination of polyurethane injection and activated oakum.

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Water leaking through concrete can lead to structural failures, sinkholes, and other costly types of property damage. For property owners, it is important to be aware of potential problem areas in your facility, factory, or residence. For concrete restoration and waterproofing contractors, it is important for your business to know where to look for leak sealing opportunities.

So where are the areas that contractors and property owners need to be looking? Here we have broken it down into two broad categories: Commercial / Industrial / Municipal and then of course, Residential.

Commercial / Industrial / Municipal

• Tanks: Water and Wastewater Treatment Plants, Aquariums
• Infrastructure: Concrete Pipe, Manholes, Pipe Penetrations, Lift Stations, Pumps Stations, Utility Vaults
• Industrial Plants: Machinery Pits, Containment Structures, Retaining Walls, Slab Joints
• Tunnels: Tunnel Segments, Retaining Walls, Headwalls and Wing Walls
• Commercial: Floors, Parking Structures, Elevator Pits, Basements
• Specialized arenas for sealing leaks in Mines, Dams, and Power Plants.

Residential

• Single Family: Basements, Foundation Walls, Swimming Pools, Fountains, Seawalls, Retaining Walls
• Multi Family: Elevator Pits, Parking Garages, Seawalls, Pools, Basements
• Farms: Silos and Tanks, Earthen Dams, Manmade Ponds

Alchemy-Spetec manufactures an effective range of polyurethanes designed to seal leaks for all of the above issues. We also strive to continually educate the market. 

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Leaking concrete structures can be permanently repaired using a water-activated flexible foam. Pressure injection of these liquid resins forces the material into leaking cracks, joints, and other defects where the resin rapidly reacts with water to form a flexible, water tight seal.

From hairline cracks to gushing leaks, virtually any of these defects can be repaired with our leak seal resins. Take a look at this polyurethane leak seal demo video.... 

Over my many years of consulting with customers on jobs, I have pumped, shot, spilled, splashed, sprayed, poured and injected polyurethane foam into every imaginable type of concrete structure known to man. Most of it has ended up where it was supposed to go. But some of it did not.

Some of it ended up on my clothes, my skin, and my hair. That never bothered me (well, maybe the resin on that brand new button down shirt bothered me a little). What is really frustrating is when it stains the concrete you are trying to fix. Your job is to repair something for your customer, and if you are not careful, you can make it look worse than before.

A few years ago I asked our chemist to develop a water based solvent for cleaning out two component impingement style injection guns (such as our MixMaster Pro gun). I wanted the product to be water based so that it could be dispensed directly into the environment with no negative effects. I also needed it to be thick enough to push reacting foam out of the gun.

After I saw what he came up with, I realized it could probably be used as a barrier to prevent polyurethane from staining concrete. After a little testing and tweaking, I realized it would work.

AP Flush 125 is a concentrated product that you can mix with 3-5 parts water. It can be sprayed onto concrete, wood, metal, or plastic and creates a barrier layer that prevents polyurethane foam from sticking to and staining the surface. You can brush it on or spray it on with a pump up garden sprayer.

Our AP Lift customers spray it right out of the MixMaster Pro gun onto concrete surfaces as they are moving from injection point to injection point. They also saturate cracks and joints that foam may come out of. This has the dual protection of keeping stains off the concrete and helps reduce binding of the concrete that can impede the lifting process.

On hot, sunny days you may have to apply it again if the water evaporates out of the system, but overall it really works wonders. We have used it on lifting jobs, soil stabilization jobs, and leak seal jobs. Now the spray foam insulation contractors are starting to use it to protect surfaces adjacent to their work areas.

Next time you are using polyurethane foam on or near a surface you don’t want your foam to stick to or stain, try a pail of AP Flush 125. One pail of concentrate can give you up to 25 gallons of protection.

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After three decades in this industry, I still find myself in awe of what polyurethane foam can do.  From sealing massive dam leaks to stabilizing airport runway slabs to lifting entire buildings – the feats contractors achieve with this stuff is astonishing.  Yet some people who are new to this technology have a hard time understanding how a mere “foam” can be ideal for these most demanding of applications.  Or maybe they wonder how safe it is. 

The irony is, whether you think you are “new” to this technology or not – you’ve been surrounded by polyurethane all your life.  Sometimes an understanding of the past can provide more confidence for moving forward into the future.  So if you can’t quite grasp how “foam” has been developed to the point that it can lift a building – or you wonder how safe it is – pay close attention to this story.

Dr. Otto Bayer first made polyurethane foam in Leverkusen, Germany in 1937.  Polyurethane was initially used as a cheap replacement for rubber.  Widespread use began in World War II, when many other materials became scarce.  Polyurethane use quickly spread as a key component in many products, from specialized paper to protective military garments to gloss finishes and protective coatings.

In the 1950s, many companies such as DuPont, BASF, Dow, and Union Carbide started producing polyurethane for an even wider variety of applications including adhesives, insulation and foam upholstery cushions.  In the 1960s the Bayer company (no relation to Dr. Otto Bayer) exhibited an all-plastic car, parts of which were made with polyurethane. 

In the early 1970s, the introduction of polyurethane skateboard wheels as a replacement for the old metal ones completely revolutionized the sport, as the new wheels allowed for high impact activities such as jumping off of ramps.  In the 1980s, the first mass produced plastic-body automobile – the Pontiac Fiero – was made with the use of polyurethane technology.

Today polyurethanes can be found in an infinite amount of products including furniture, clothing, shoes, beds, moldings, etc.

In the 1960s, 3M Company in the U.S. and Takanaka in Japan both introduced polyurethane grouts.  3M’s product was called Elastromeric Sewer Grouting Compound.  As the name indicates, it was intended for use in underground utilities.  Takanaka’s product was called Takanaka Aqua-Reactive Chemical Soil Stabilizer (TACSS).  As the name indicates, it was intended for use in soil stabilization projects.  In the early 1980s, DeNeef obtained the rights to TACSS and began distributing polyurethane grout worldwide.  By the mid 1980s, there were almost a dozen manufacturers of polyurethane grouts.  I got my start pumping 3M 5600 to seal cracks in the Atlanta subway system back in 1985.  I was amazed at what it could do back then, and I am still amazed at what our products do today.  3M exited the business many years ago.

In the last few decades, polyurethane grouting has become a widely accepted method for sealing leaks, stabilizing soil and lifting slabs.  Many innovations have been made, including closed cell hydrophobic polyurethanes and the use of two-component foams in geotechnical engineering.  Polyurethane’s advantages over the old school approach of cement grout repair is covered thoroughly in our blog post Polyurethane vs. Cement for Slab Jacking.

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In a recent media interview, I was quoted as follows: “Ultimately, the customer is the property owner, somebody who’s got a problem. Even though we’re selling to contractors, we kind of all have to be on the same page.” That view has motivated us to pay close attention to what contractors, engineers AND property owners are most concerned about regarding the use of polyurethane. Over the years, we’ve noticed three main questions that arise over and over again:

1. Are the polymers strong enough?
2. Are they easy to install?
3. How quickly can the job be finished?

So we’re going to take a look at each of these three core issues in detail…

Powerful Polymers

Concrete Leveling Foams

In my blog post Slab Jacking With Polyurethane Foam – How Strong is Strong Enough?, I point out that the National Home Builders Association and the International Building Code list stiff clay as having a 4,000 lbs per square foot load bearing capacity and crystalline bedrock as having 12,000 lbs per square foot capacity. Our lifting foams have load bearing capacities of 7,200 to 14,000 lbs per square foot after curing in a free rise state. 

When Alchemy-Spetec foams cure in a confined state underground, that bearing capacity has been known to be even stronger. Testing data in the lab shows that our lifting foams will increase in compressive strength: In a space confined 25% by volume there will be an increase of 31% in psi and in a space confined by 75% there will be a 79% increase in the psi.

The Alchemy-Spetec lifting foams are used to level airport slabs supporting jumbo jets, heavy equipment, building slabs supporting tremendous loads, and even railway slabs supporting the heaviest freight trains.

Leak Seal Resins

Alchemy-Spetec leak seal resins have been used in many applications, including shutting down a 2-million gallon per day leak at a water treatment plant. The leak was reduced from 1,700 gallons per minute to just 10 gallons per minute (attributed to the many vintage valves and fittings that are still present at the plant). They are also used in other applications such as curtain wall grouting.

Soil Stabilization Resins

Unstable, eroded, or loose soil around infrastructure can result in settlement and damage to the structure. Voids can be filled, seawalls remediated, soil consolidated, and water migration halted by injecting the soil with Alchemy-Spetec soil stabilization resins. In my blog post Soil Stabilization Products Prevent Cave In Beneath Busy Intersection, I profiled a powerful example of AP Fill 700 in action. Inspectors in Orange County, Florida found a depression in the middle of a busy intersection that was due to an underground sewer line that wasn’t sealed. Water and eroding soil were infiltrating the sewer line causing the road to slowly settle. The resulting voids around the drainage structures had the potential to grow larger, eventually resulting in a complete cave-in of the roadway. A point repair was done from within the leaky pipe to stop the infiltration but they feared it was only a matter of time before the road gave way. We devised a solution for their crew to use the versatility of AP Fill 700 as both a permeation and void filling grout.  To keep the lane closure down to a bare minimum of time, the project was successfully completed on two separate Saturdays. The voids were filled, the loose soil was solidified, and only minor asphalt patching was required to make that area smooth for traffic again.

Orange County Utilities Supervisor Paul Morrison has been enthusiastic about AP 700 since the first time he tried it out on a severe manhole leak, when he had this to say…

“Based on our extensive prior experience, we expected to use at least five to ten pails to stop this leak. With Alchemy-Spetec material we were able to do the job with 1/10th of that amount. Their product will save our crews a lot of time and labor, and save the taxpayers of Orange County a lot of money.”

AP Soil 600 is one of the most versatile permeation grouting products on the market. It can be characterized by its single component, moisture activated, hydrophobic, and low viscosity qualities. It can fortify sandy soil to strengths approaching 2,000 psi.

Painless Procedures

As I never fail to point out, application procedures for Alchemy-Spetec products are relatively painless. The installation process is very clean compared to replacing the structure or repairing with cement grout.  Polyurethane is lighter than cement, so it doesn’t sink. Alchemy-Spetec products do not shrink after installation. The closed cell structure makes these resins impermeable. 

Rapid Results

Application of polyurethane is usually less expensive than replacement. Polyurethane concrete repair is also less time consuming. Any structure repaired with Alchemy-Spetec products is usually ready for use 45 minutes after application.

There you have it – the three most critical issues for contractors, engineers and property owners regarding polyurethane concrete repair. By staying focused on these concerns we constantly remind ourselves WHY we do what we do. We do it for YOU.

Want in-depth info on polyurethane infrastructure repair resins?

As a technical consultant, I often assist customers when they're put to the test with difficult jobs. That's why we go out of our way to provide the powerful polymers and painless procedures they need to achieve the rapid results those projects require. For an in-depth dive into what we mean by powerful, painless and rapid - see this blog post I wrote awhile back. Then watch the video below to see powerful polymers, painless procedures, and rapid results in action... 

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The Spetec PUR H100 Hotshot Cartridge contains Spetec PUR H100, a one component, closed cell, hydrophobic, water reactive, solvent/phthalate free, low viscosity polyurethane injection resin for stabilization and water cut-off of large water leaks. The cartridge packaging is ideal for small jobs in locations that prohibit the use of pumps.

Advantages:

• Single component cartridge.
• Good compression strengths.
• Rapid set time.
• No volatile solvents.
• Cures to rigid foam.

Applications:

• Water cut-off.
• Dams.
• Manholes.
• Storm pipe joints.
• Box culverts.
• Limited access areas.

For details on preparation, application instructions, required tools and more, please download this Spetec PUR H100 Hotshot Cartridge datasheet.

Want more information on Alchemy-Spetec leak seal products?

Chemical grouts are commonly injected into leaking cracks and joints to stop the flow of water, sealing off cracks and filling voids. This procedure can be performed in both wet and dry situations, in potable water or wastewater tanks, and in a variety of other structures where water is leaking.

Procedure

Identifying and Preparing the Structure

• Clean crack surface using a wire brush, a grinder with wire cup wheel or other mechanical means, to remove mineral deposits, coatings or other debris. Pressure washing of the surface is also an option. If sever contamination exists, a chemical cleaner may be used, but must be flushed or neutralized before proceeding to the next step.
• When addressing wide cracks, use Oakum, hydraulic cements or epoxy gels as a surface seal over the crack prior to injection to contain chemical grout in the structure. When addressing high flow leaks, use Oakum soaked in chemical grout. Soak oakum in chemical grout and insert into the leaking crack or joint with a screw driver or similar tool. This will slow the water flow.
• pH notice: water used to activate Alchemy-Spetec chemical grouts must be in the pH range of 3-10 to achieve optimum performance.

Injection Port Spacing and Drilled Holes

• Port spacing is determined by the width of the crack: 3-4 inches apart in tight cracks and up to 24 Inches apart in wide cracks. Staggering ports from side to side (stitching) is always recommended.
• To intersect a crack at the mid-point, drill injection port holes toward the crack at a 45-degree angle, at a distance of one-half the thickness of the concrete. Example: In 12-inch-thick concrete, drill the injection port hole 6 inches back from the crack at a 45-degree angle to ensure crack is intersected at mid-point (longer drill bits may be needed to reach mid-point). See Diagram.
• Drilled holes should intersect the crack or joint at the midpoint, so the chemical grout can enter the crack in the center of the concrete and expand in both directions sealing the entire crack, filling any voids and micro cracks in the structure as the material expands and cures.
• Drilling injection holes is commonly performed using 3/8, ½, or 5/8-inch diameter drill bits.
• Flush drilled holes with clean water to remove dust and debris before inserting drive in port or mechanical packer.

Installing Injection Ports / Packers

• Various types of drive in ports and mechanical packers are available in the market.
• Drive in ports should be driven/hammered into the drilled hole until snug.
• Once the port is snug in the hole, insert a grease or zerk fitting into the port. Insert mechanical packers into the drilled holes until the top of rubber sleeve is just below the concrete surface.
• Tighten the packer using a wrench or ratchet, turning clockwise until firm. Do not over tighten.
• Install each port before injection but leave the grease coupler/zerk fitting off so you can monitor the travel.
• Avoid hammering on the grease coupler/zerk fitting.

Equipment and Equipment Set Up

• When using chemical grouts that are water reactive, use two separate pumps: one for water and the other for chemical grout. Caution: Never allow water to enter the chemical grout pump.
• Flush out the chemical grout pump and lines prior to use with an approved pump cleaning agent. This will ensure that the pump has no moisture in the system. Repeat flushing procedures when injection operations stop for a prolonged period of time.
• Pump hoses should be equipped with a high-pressure ball valve assembly. This allows easy connection to the injection port and an on-off grouting operation.
• Keep injection pump pressures low at the beginning of injection and increased slowly as needed to achieve full grout penetration. Extra high pump pressure may result in cracking or spalling of the concrete.

Flushing the Crack Prior to Injecting

• Flush the crack prior to injecting chemical grout to ensure that the crack is free of debris, that injection ports have intersected the crack, and that there’s enough water to cause the resin to react.
• Begin injecting water at the lowest port on vertical cracks or at one end (and then work across) on horizontal cracks. Continue injecting water until the crack has been flushed and clean water appears.

Injection of Chemical Grout

• Inject the liquid (catalyzed) resin into the injection packer.
• When injecting a vertical crack, start at the bottom and work upward as the material seals the crack.
• When injecting a horizontal crack, start at one end and work across the crack.
• REMEMBER: Keep pump pressures low at the beginning of the injection process and increase slowly as needed to achieve full grout penetration. Extra high pump pressures may result in cracking or spalling of the concrete.
• Inject at a rate that allows material to travel and completely seal the crack. Once you see material seep out at the adjacent port, pause injection and insert a grease coupler/zerk into that port. Then resume injection on the existing port.
• Advance to the next port when movement of material has stopped on the existing port, or when material is exiting the crack at an excessive rate.

Completion and Clean-up

• After fully injecting the crack with chemical grout, attempt to re-inject water into each port to ensure that the crack and drilled holes have been completely sealed.
• Next, remove each injection port/packer by pulling the port/packer out of the structure, or by drilling them clear to below the surface by 3 inches or more.
• After removing the ports/packers, fill the injection holes with hydraulic cement, non-shrink grout or epoxy gel material.
• Remove any wasted cured resin, used ports/packers, and construction debris.

COMMON MISTAKES TO AVOID

• Drilling too close to the crack can cause spalling of concrete.
• Drilling too close to the crack will not allow material to seal entire crack, which can result in re-occurring leaks.
• Injection of cracks with manual equipment (ex. grease guns) will not produce enough volume and may cause extreme waste and injection failure.
• Poor preparation of wider cracks may cause material waste, lea–ding to re-occurring leaks.
• Injection pump pressure which is too high can cause spalling and damage to the surface.

Chemical grouting for leak-seal applications can provide contractors a specialty repair service that will always have relevance and demand in below-grade structures and water-holding structures. By following these steps for product, packer, and pump selection, you will be on the right path to a successful leak-seal repair. For more details and information on the leak-seal methodology, please contact a knowledgeable Alchemy-Spetec team member.

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Once the material is selected, an appropriate piece of equipment must be selected for dispensing the material. For most polyurethane injection resins, single component high-pressure piston pumps are required. These are typically electric airless design, but can also be pneumatic, drill-operated, or hand powered. Alchemy-Spetec offers the full line of Titan pumps with various ranges of pressure and volume. The Titan 440 is a good pump for small injections, or to act as a water flush pump to clean drill holes and to ensure drill hole intersects the crack or joint. For higher outputs, it is recommended to use the Titan 640 or PowrTwin 8900. These pumps will be much better equipped for large volume applications such as curtain grouting, or for single component soil injection applications. For small cracks and joints, Alchemy-Spetec offers the Drill Pump. The Drill Pump is drill-operated and capable of handling pressures as high as 5000psi. It is easily maintained and produces very minimal waste due to the small hopper size and mixed batches. For acrylic injections, a stainless-steel pump, the Alchemy-Spetec Gel Pump is required. Due to the oxidizing nature of the B-side sodium persulfate, stainless equipment is required. 

The coupler at the end of the hose set will be dependent upon the type of zerk fitting discussed in part 2 of this blog series. A button-top valve requires a sliding coupler, the Alchemy-Spetec ACP-2204, or the standard zerk coupler, ACP-2201. It is always recommended to have several couplers on-site as the injection grouts will eventually cure in the couplers and prohibit the passage of material. It is also recommended to keep a spare piston kit or packing kit for any pump and to have received training on the appropriate replacement technique should it need to be changed. 

Chemical grouting for leak seal applications can provide contractors a specialty repair service that will always have relevance and demand in below-grade structures and water-holding structures. By following these steps for product, packer, and pump selection, you will be on the right path to a successful leak seal repair. 

Want more information on building a leak seal methodology?