Alchatek Blog

Unstable soil can be defined as soil that will not stay in place on its own, and therefore requires extra support. It should be noted that unstable soil can threaten the stability, security, and safety of infrastructure and can damage, degrade, and even destroy a number of structures, such as buildings, bridges, and roads.

Let's look at the four main causes of unstable soil...

Erosion

Erosion refers to processes in which external elements (wind, water, etc.) remove soil or rock from a certain location and transport it to another location. There are a variety of different erosion types, including river and gull erosion, wind erosion, and erosion attributed to human activity. Erosion ultimately destabilizes soil and can lead to landslides and sinkholes.

Poor Compaction

One of the most common causes of unstable soil is poor compaction. In some cases, certain types of soil are simply very loose and subsequently not compact. The cause of this is typically an imbalance of mineral pieces, organic matter, air, and water. For example, a clay soil with very high moisture content will inevitably become instable, as it will be incredibly difficult to compact. Similarly, soils with high sand content will be difficult to compact.

Freeze/Thaw

Processes of freezing and thawing essentially accelerate erosion processes. Cold weather freezes moisture trapped in tiny cracks. When this water freezes, it expands, subsequently pushing on the rocks and breaking them into smaller pieces. As processes of freezing and thawing continue, rock and sediment are continually broken down.

Decomposition

When soils contain a high concentration of organic materials, such as topsoil and plant matter, it will decompose, subsequently causing it to become unstable. This is because organic materials rapidly change form and mass as they decompose in soil. In fact, up to 90 percent of organic material will disappear over the course of the decomposition process.

Fortunately, stability can be restored to soil with ultra-low viscosity polyurethane resins. Foaming and permeation polyurethanes can mitigate the damage done by processes of erosion, decomposition, and freezing and thawing, as well as help to rectify compaction problems. When it comes to unstable soil, you can’t afford to take a risk. Stable soil is crucial to maintaining secure structures.

Want in-depth info on soil stabilization procedures and products?

Not all two-component polyurethane lifting and stabilizing foams are specifically designed for wet environments.  In most situations when you are injecting polyurethane foam into the ground, there is a high probability that the environment is going to be wet.  You need to be confident that the foam will react and retain the desired properties in these wet environments.  If the foam you are using is not specifically designed for wet environments, then you may be cheating yourself and your customer out of the best possible results.

All polyurethane foams are going to undergo a density change when introduced to water.  This is precisely because the isocyanate (A component) in polyurethane reacts faster with water than it reacts with the polyol (B component).  Some will undergo drastic changes and some minor changes.  It is important to feel confident that the foam you are using will only undergo minor changes.  The density of the foam is very important because density correlates to foam strength, and you are relying on that strength to support the structure you are lifting or the soil you are stabilizing.

All Alchemy-Spetec products are formulated to achieve minimum density changes when introduced to wet soil.

Want in-depth info on slab lifting procedures and products?

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.

Want more in-depth info on polyurethane and chemical grouting?

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... 

Want more in-depth info on Alchemy-Spetec products?

Acrylic polymers are noted for transparency, resistance to breakage and elasticity. Spetec AG200 is a three-component, water-swelling hydrogel based on acrylic that hardens into an elastic product. It's a great choice for fixing leaking cracks and joints in walls. This product is also used in curtain wall grouting applications for soil stabilization.

The main benefit of Spetec AG200 acrylic is its very low viscosity. The viscosity of water is 1.002 centipoise (cps), which is very thin. Spetec AG200 is 4.2 cps which allows this product to penetrate deep into concrete cracks, and also permeate soil very thoroughly. Another benefit is the product's tenacious bond to concrete.

Flexibility in set up time is another key feature. Spetec AG200 can be made to set up anywhere in the range between 15 seconds to 60 minutes. With the fast set time option, you will be able to shut down very active leaks quick. With the slow set up time option, you will be able to permeate soil very effectively before the material sets up.

Want more information on Alchemy-Spetec soil stabilization products?

Today is our last day exhibiting at the No-Dig Show!  Visit us at booth #146!

Watch this video to preview a couple Alchemy-Spetec product demos!

Want more information on Alchemy-Spetec products?

We are proud to announce that we are currently exhibiting at the No-Dig Show in Palm Springs, CA. Visit us in Booth #146!

"NASTT’s No-Dig Show is the largest trenchless technology conference in North America, where professionals attend to learn new techniques that will save money and improve infrastructure. This show offers six tracks and 160 peer-reviewed, non-commercial presentations, including case studies detailing environmentally friendly trenchless solutions and cost-saving opportunities for municipalities and utilities. With over 190 exhibiting companies and multiple networking events, spend quality time with current colleagues/customers and grow your connections. Whether you’re a newcomer or a show veteran, NASTT’s No-Dig Show is the must-attend conference for underground infrastructure professionals."

Click here to read more about the No-Dig Show.

Reps Attending: Jim Spiegel, Thad Brown
Polyurethane Solutions Demonstrated: Seal Leaks, Stabilize Soil, Lift Slabs
Booth Number: 146
Address: Palm Springs Convention Center 277 N. Avenida Caballeros, Palm Springs, CA 92262 

Want more information on Alchemy-Spetec products?

Hydroactive chemical grouts, by definition, require hydrogen molecules from water to initiate the polymerization reaction.  Typically, an ISO component is catalyzed by an amine, but this solution will remain unreacted until it comes in contact with hydrogen.  All of the contractors out there familiar with chemical grouts are familiar with the ‘skin’ on the top of a catalyzed batch.  This is simply the top layer of the catalyzed batch showing signs of initiation just through contact with moisture in the air.  For injection into active leaks, these products are a slam dunk.  But what happens when you get to the job, and there is no leak where there was one just a few days ago? 

Most manufacturers will provide the generic answer of ‘just introduce water.’  And in layman’s terms, this is accurate.  But what is the CORRECT way to introduce water?  Twin streaming through an F-Valve Assembly is perhaps the most proven technique to ensure adequate and thorough activation of hydroactive grouts.  An F-assembly is an applicator apparatus designed specifically for twin streaming multi components.  This can easily be achieved through the use of two pumps, one designated for water and another designated for chemical grout.  This will also prevent the leaking resin phenomenon sometimes observed following mechanical packer removal. 

Alchemy-Spetec supplies F-assemblies and the following hydroactive grouts: Spetec PUR H100, Spetec PUR F400, Spetec PUR F1000, Spetec PUR H40, AP Fill 700, and AP Soil 600.  For application recommendations and guidance, call an Alchemy-Spetec consultant now at 404-618-0438.  Don't rely on suppliers who simply promise a universally easy application process.  Lean on the suppliers who teach you how to navigate the unique challenges that each job site inevitably presents. 

Want more information on Alchemy-Spetec hydroactive grouts?