Alchatek Blog

Ports are generally used to deliver resinous material and seal vertical or overhead cracks in concrete with epoxy or polyurethane chemical grout. 

Using Ports with Epoxy

For epoxy applications, ports are set directly over or into the crack. Epoxy is injected directly into the crack. A low viscosity epoxy needs to get at least 90% penetration and fill of the crack for a structural repair. It is not necessary to drill into the crack to set the ports for epoxy injection. “Top Hat” ports can be used to set and seal cracks. This seal creates a reservoir for the epoxy by not allowing any of the resin to leak out during and after injection.

Using Ports with Polyurethane

Polyurethane crack injection is done differently. Holes are drilled at a 45 degree angle to the crack in an attempt to meet the crack at its mid-point in the concrete membrane. Injecting the grout into the mid-point of the crack allows for expansion in all directions for a complete seal.

For polyurethane curtain wall grouting, holes are drilled completely through the wall in a pre-determined grid pattern and ports are set for the injection site. This method allows the crack or joint to be sealed from behind the wall. It is important to make sure you know where the steel reinforcing, possible post-tensioned cables, electrical conduit or any other systems that may be in or behind the wall are before drilling.

Polyurethanes and Epoxies

As mentioned in a previous blog, Polyurethanes vs. Epoxies, there are many different situations requiring either product type. The choice depends on the project at hand and the depth of your product knowledge.

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When repairing cracks in concrete, which material is better to use? Polyurethane or epoxy?  Well the real answer is both products will work, but there are some rules that apply.

Polyurethanes Vs. Epoxies

If the crack is leaking, polyurethane chemical grout would be the better choice because epoxies do not perform well where moisture is present. Polyurethane is a fast setting foam product that can stop leaks in as little as 5 seconds. It can also fix hairline cracks and cracks that are a few inches wide. 

Epoxy can be used for cracks in need of structural repair because of the high compressive strengths they have. Some epoxies even have higher strength ratings than concrete. This is why they are the best choice for non-leaking structural cracks.

A few years back I was asked by an engineer to look at a parking garage that had many leaking cracks. It turned out that those cracks were previously repaired with epoxy grout. This is a perfect example of why grouters should not use epoxy in leaking cracks.  As I mentioned earlier, epoxy does not do well in cracks that have moisture in them.  The other mistakes they made were: using a very rigid epoxy without flexibility, and failing to bridge the crack for movement. This is what caused the cracks to leak again.

My recommendation for this problem was a simple. Because the cracks already had epoxy in them, I had the contractor drill through the wall and into the soil. I then had the contractor pump polyurethane chemical grout behind the wall and build a curtain wall of grout behind each crack.  Problem fixed!

Products we have for crack injection:
Spetec PUR F400
AP Seal 500 

Products we have for curtain wall grouting:
Spetec PUR H100
AP Fill 700   

Product we have for structural crack repair:
Epicol INJ LV

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Pipes that are fed through foundation walls are subject to leaking over time due to corrosion, pressure or cracks around the pipe.  This takes place because water essentially weakens the concrete around the pipe and creates leaks.

When these particular pipes are put in place, contractors usually drill a hole through the wall and insert pipe sleeves to hold the conduit, sewer pipe or water line.  Most of the time water will leak from the back of the wall where the soil has eroded and then through the sleeve and out on to the floor.

Qualified contractors can use Alchemy-Spetec polyurethane water activated chemical grouts and oakum to repair these pipe penetration leaks.  (Oakum is a oil-free natural fiber that is used for filling voids.)

Here's how it's done:

1. Soak the oakum in chemical grout, and then quickly submerge it in water. 
2. Immediately pack the oakum around the pipe that is sitting in the sleeve.  It will harden in minutes and become a tightly sealed gasket. 
3. If needed, use an injection needle to fill area behind the oakum with chemical grout.

Alchemy-Spetec products that can be used include:

• Oakum
• Spetec PUR H100
• AP Fill 700

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Parking garage leaks can cause many issues for property managers when it comes to city code upkeep.  A major sign that a parking garage needs repair is evidence of water intrusion. The longer this evidence is ignored, the bigger the cost for the property owner in the long run.

One obvious sign of water intrusion is sudden ponding or free standing puddles on the concrete.  Another telltale sign is efflorescence on your walls and floor.  Efflorescence is the migration of salt to the surface of porous material where it forms a powdery white coating.  Efflorescence occurs when wall or floor cracks begin to leak water over a period of time.  If you see exposed rebar in a parking garage, it's a sign that water may be going through cracks, spalling the concrete and exposing the rebar.  Once this happens, the exposed rebar begins to rust and then has to be replaced soon after. Replacing rebar can be costly.

Alchemy-Spetec products are ideal for the Crack Injection or Curtain Wall Grouting procedures that are used to address these issues.  

Crack Injection	Curtain Wall Grouting
Spetec PUR F400	Spetec PUR H100
AP Seal 500	AP Fill 700

When chemical grouts are injected into the floor or wall cracks, they provide a durable and lasting seal to prevent further leakage.  This can prevent concrete from spalling and exposing rebar, eliminate future puddles from forming and stop expansion joint leaks.

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Elevator pit water leaks are very common. These pits can be open to flooding and leakage because they are usually at the lowest point of a building below the water table. Water can easily seep from cracks in the walls or through the floor wall detail.

There are many reasons why elevator pits leak.  This can include incorrect application, damage to existing elevators, pits that are very old, changes in the water table, and even shortcuts that have been taken such as non-installation of waterproofing materials. These are just a few of the causes.

So what happens when these elvator pits become consumed with water?

The solution is simple!

You would drill holes through the walls and floor using a grid pattern.  You would then pump water activated polyurethane chemical grout into the soil to create what we call a “curtain wall”.  This wall essentially stops the water from penetrating the area around the pit.  It creates a permanent seal and allows the elevator to function properly again.  (If you're a property owner, we can help you find a contractor to do this.  Just call us at 404-618-0438.)

Alchemy-Spetec products that are used for curtain wall grouting include:

Spetec PUR H100

AP Fill 700

Spetec AG200

If you are unfamiliar with the term "curtain wall" and what it includes, be sure to check out our previous blog series on Curtain Wall Grouting to gain a deeper understanding of the process.

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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.

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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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