Alchatek Blog

Polyurethane chemical grouts fall into two categories when it comes to how they relate with water: hydrophilic and hydrophobic. 

Hydrophilic grouts are ideal for areas that are constantly wet, because they bond better to wet concrete.  They are water loving grouts which means they thrive in moist environments.  They perform very well when they are subjected to water 24 hours a day. 

However, if that water goes away, hydrophilic grouts are not ideal because they could shrink and crack when the area dries out.  Now you take that chance it will leak all over again on the next rain event.  We call this a wet/dry situation.  What does wet/dry situation mean?  This means that water can be present in a crack or void after a hard rain and then a few days later that water is no longer present in the crack and void.  The water table drops or the weather dries out and now you have a crack or void with no moisture present.  In situations like these, you want to use a hydrophobic grout.

This leads me to a call I received a few months back.  The owner of a storage building in Virginia was upset because he had hired a grouter to come to his storage facility and fix leaking cracks inside the storage bins. While the leaks remained sealed initially, they eventually started leaking again after a few rainy day/sunny day cycles.  They were very worried that water was going to leak and damage the items that customers had in the storage units.  It turned out the contractor had used a hydrophilic grout in this wet/dry situation, which was not the best choice for the reasons explained above.

The solution was simple.  The owner went with my grouter, who used a hydrophobic grout to permanently seal the leaks.  Knowledge is power, folks!

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Condition the Materials

So how do you fight the cold?

1. Keep the material warm - we consulted with one of our customers on a job in Canada last year and there was a giant void full of approx 45° F (7° C) water right behind a vault we were injecting.  We kept the AP Fill 700 in a hot van and pumped through insulated hoses.  
2. Adjust the Catalyst - on the above project we used the fastest catalyst we have for our AP Fill 700.  With a 10% AP Cat 107 to resin ratio, the material reacted almost immediately and our customer was able to fill the void and push out the water.
3. Inject further away from the leak - sometimes in a buried vault or pit, you may have to grout behind the structure to create a curtain wall effect.  If a joint, crack, or pipe penetration is leaking, and you have slow-reacting resin pushing through, you need to inject further away from the leaking area to give the material more time to react.  These polyurethane foams will find the leak.  Move further away and let the material do the work.
4. Twin streaming - we have twin streamed polyurethane and warm water in some cold weather applications.  This gets the polyurethane reacting as it's being injected, rather than hitting cold water and having a shock to the temperature of the polyurethane.  Click here to read an entire blog article on twin streaming.

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How many times this year have we found ourselves saying "they need to try some 700"?  Too many to count.  Time and time again, the AP Fill 700 has stepped up to the plate when other products could not get the job done.  

AP Fill 700 is a single component polyurethane injection resin that reacts when it comes into contact with water or moisture.  It can be premixed with a catalyst which will make the resin react as a foam to fill voids or shut off leaks.  It can also be injected without a catalyst as a pure permeation resin to stabilize soil.  

I thought it would be a good time to emphasize the versatility of this amazing polyurethane resin by highlighting one of its unique applications:

Void filling and water cutoff around buried culverts.  

Concrete pipes, boxes, and corrugated metal culverts are often used to help small creeks and streams transition underneath roadways and rail lines.  In times of heavy rain or just from years of the erosion process, water will find its way beneath the culverts and around the sides.  This causes undermining of the culvert and also erosion of the soils above.  Dips in rails and roadways can become evident as the undermining process occurs.  AP Fill 700 can fill these voids even in times of high water flow.  When mixed with AP Cat 107, the reaction time is barely seconds.  

Several times this year, pipe relining contractors were struggling with these culverts, trying to stop high water flow and fill voids with products that were too slow.  They reached out to us for help and we recommended the 700 with a 10% Cat 107 to resin ratio.  The results speak for themselves as we have won over many converts with this product.  The additional benefits of it being NSF / ANSI 61 approved and phthalate free only add to the appeal.

Want more information on Alchemy-Spetec leak seal products?

Part of managing a stormwater or sewer system involves vacuum, inspection and sealing. Municipalities that own these systems either do this work themselves or sub out a portion or all of the process. Here’s an overview of the process:

Assuming that the pipes have been vacuumed, your next step is to inspect them with a remote operated pipe crawler camera (as depicted in the bottom left side of the graphic below). You can use these types of cameras to thoroughly inspect the area.  In particular you’re looking for separated joints and cracks which exhibit water infiltration. The video is monitored from the street level. 

The images coming from the camera’s location in the pipe are compared with existing plans or blueprints for the sewer or stormwater system. When leaks are observed below, the point on the ground directly above is marked for insertion of a grout pipe. You continue this process until all the repair spots are marked on the  ground above.

After all the points are marked, your injection crew begins driving the grout pipe(s). Once the pipe(s) are in position, you inject AP Fill 700 or Spetec H100, while continuing to monitor via video. When the observed water infiltration is cut off, you stop the grouting process. Your choice of product, combined with your specific amount of catalyst or accelerator, depends on the exact conditions you are working with.

The end result is a sealed system where pipe joints and manhole structures are stabilized, sealed and protected from further infiltration. As always, you can rely on Alchemy-Spetec’s expert tech support for answers to any questions regarding this procedure.

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What Causes Leaks & Voids in Concrete Infrastructure?

Imperfect Construction

Concrete construction is by no means a perfect science. New construction often requires leak seal treatment follow up work. If the initial construction isn’t properly sealed at the time of construction, leaks are bound to appear sooner rather than later.

Weather and Wear

Concrete naturally decays over time. Exposure to extreme hot temperatures and extreme cold temperatures can take their toll over time. Even structures located in mild climates will begin to decay purely due to the aging process.

Unstable Soil

Unstable soil can undermine the integrity of concrete structures to cause cracks and voids to appear. Loose soil has four main causes: soil erosion, poor compaction, freeze/thaw cycles, and biological decay. If soil is the main culprit, additional stabilization and slab lifting treatments may be required in order to prevent further cracks from appearing.

How Does Injection Grout Help?

Water Activation

Leaking concrete structures can be permanently repaired with concrete crack injection by using a water activated flexible foam.

Pressure Injection

Pressure injection of these liquid polyurethane resins forces the material into leaking cracks, joints, voids and other defects.

Flexible, Watertight Seal

After the polyurethane crack injection is complete, the polyurethane resin rapidly reacts with water to form a flexible, watertight seal.

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As I wrote in a previous blog post The Benefits of Buying Through Distribution:

1. A distributor can serve as a one-stop shop.
 
2. Local distributors serve as experts in their area. (They often have the scoop on new projects, change orders, supplemental materials, and emergency repair needs.)
 
3. Having a distributor on hand is extremely convenient. Nothing is worse than having to call the factory again to have more product shipped after a mis-calculated estimate.
 
4. Many distributors actively work to get products specified for local jobs. That in itself can be a huge benefit. The distributor in a sense can sometimes be an extended part of your sales force.

With those benefits in mind, we publish a semi-regular Distributor Profile Series to provide more information on Alchemy-Spetec's distribution network.

In this article, we feature Indcon Inc.

They are an industrial maintenance solution provider, supplying repair materials to the industrial maintenance and construction industries.

Established in 1998, Indcon was formed in Lexington, South Carolina by Tony and Jean Atkins as a small family-run operation. The company grew quickly through their combined efforts and soon outpaced their limited capabilities. As business opportunities grew, so did Indcon, spreading its footprint first across the Southeast and later into the rest of the country. Indcon quickly outgrew its original office and eventually established a warehouse operation in Columbia and moved the company headquarters to Greenville, South Carolina.

Today, Indcon’s reach is nationwide. With sales professionals and locations placed strategically throughout the country, they are able to assist customers throughout the country to quickly get exactly the expertise, products, and services they need to reach optimum performance.

Indcon offers next day delivery to most locations on the East Coast!

A few Alchemy-Spetec items you'll find at Indcon Inc:

I recently consulted with LJS Waterproofing on a job involving leaking concrete slabs. This job involved a control joint (a planned crack which allows for movement caused by temperature changes and drying shrinkage). The joint seal that had begun to leak rain water into a conference room below.

To fix this problem, I suggested the use of Spetec F400. This polyurethane resin was chosen due to its high flexibility. When dealing with structures that move, such as parking decks, you do not want to use a resin that is rigid in any way. It will lead to cracking in the near future, which can result in job failure.

Armed with Spetec F400, LJS Waterproofing contractors began drilling into the control joint and pumping resin. After filling in the cracks, the leaks were completely repaired - with no water leaking into the room below. This job was completed within one work day.

Want more information on leak seal with Alchemy-Spetec resins?

 

As I stated in a previous blog post, Polyurethane Leak Seal in Cold Weather, twin streaming can be an effective way to ensure that water reactive resin sets up quickly and thoroughly after injection. In that post I only mentioned twin streaming briefly. Here are some more details:

What is Twin Streaming?

Twin streaming is a technique in which you use a high pressure F-valve to inject resin AND water at the same time. As you can see in the photo, the F-valve has two supply connections - one for water and one for resin. The water and resin come into contact right before they exit the nozzle.

Advantages:

1. Ensures there is enough water for the resin to react with.
2. Starts the reaction immediately.
3. Allows you to inject in cold water.

When Filling Voids Above the Water Table

When working on jobs that require void filling behind walls, also known as curtain grouting, it is imperative that you are prepared for any obstacles that may occur. If the voids are large and dry, resin may not have enough water to react with when injected in the conventional manner. In this case injecting water behind the wall prior to injection might not be sufficient (especially if the void is open or filled with gravel, giving the water an easy path to escape). With twin streaming you are guaranteed there is enough water for the resin to fully react and fill the voids.

While Injecting Under Cold Water

Twin streaming also works well if you find yourself having to inject into a cold, underwater environment. You can inject warm water along with the resin to jump start the reaction process before the cold water gets a chance to slow down the process.

The ratio of water to resin can be controlled by opening the valves at different angles. Some products such as AP Fill 700 and Spetec H100 only need a little water to react with (10:1 resin to water is plenty). In this case, you would crack the water valve slightly, then open the resin valve all the way. Other products such as AP Seal 500 and Spetec GT350 need more water. A 2:1 or 1:1 ratio of resin to water both work well. In this case, you may want to open both valves all the way.

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Infiltration of ground water into storm and waste water systems is a huge issue for many municipalities. This earlier blog article on the subject is an excellent resource.

As Andy Powell states in his post:

Aging sewer and storm water systems across the country are plagued by infiltration and inflow; especially in areas with high water tables and sandy soils. Over time, compacted soils around catch basins, manholes, and culverts relax and result in deflection of joints and pipe connections. The end result is infiltration of ground water into the storm and waste water systems. This infiltration erodes the soils surrounding below grade drainage structures resulting in sinkholes, settling roadways, and property damage; not to mention the extra cost of treating that uninvited ground water.

But luckily there is a solution:

The solution is a combination of sealing leaking joints both from within the drainage structures and through point grouting from street level. Expansive polyurethanes such as Spetec F400, Spetec F1000, AP Seal 500, Spetec H100 and AP Fill 700 produced by Alchemy-Spetec can be injected directly into pipe and manhole connections where they react with infiltrating water and expand to seal off leaking joints. Additional point grouting from street level fills voids and permeates loose soils. This relieves hydrostatic pressure from the structures and strengthens the ground to support the above roadways and sidewalks.

Want more information on infrastructure leak seal & void fill?

I recently had the opportunity to train a crew on a very interesting job inside an underwater utility tunnel beneath a lock and dam in the St. Lawrence Seaway. This seaway connects the Great Lakes to the Atlantic Ocean. This tunnel is underneath a giant concrete deck, so the walls have taken a lot of pressure over time. The soil also shifts and settles underneath the tunnel as the years go by. Those factors, in addition to freeze/thaw cycles have caused cracks to appear in the walls.

One particularly large crack was 20 feet long and up to 2 inches wide in some places. The water leaking through created an especially dangerous situation considering the 480 volt electrical box you can see in the photo above. There is also plenty of valuable equipment in the tunnel that is susceptible to water damage.

I suggested to the customer that they buy about four 5 gallon pails of Spetec F400. I recommended this material because it works very well in wet joints and cracks. It also remains somewhat flexible after installation, so if the walls settle or shift a little more, the cured grout will not break. When I showed up we got to work immediately with our on-the-job training, using modified airless sprayers to pump the material.  Overall, it took about 2.5 hours for the crew to get the job done while learning the leak seal process at the same time.

Want more info on sealing leaks with chemical grouts?