Polyurea Coatings: A Solution for Aging Water Tanks

March 22, 2016

This Trial Project Launched a Brand
For more than a decade spanning 1996–2006, Bostonians were subjected to endless traffic snarls during the massive “Big Dig”—that many say was “the most reported civil project in the world” as Massachusetts took Interstate’s 93 and 90 from above ground to 50 feet below ground, and under water.

But the Big Dig, says CEO David Cerchie of VersaFlex, “is how we got our first big break that put us on the map.”

This Trial Project Launched a Brand For more than a decade spanning 1996–2006, Bostonians were subjected to endless traffic snarls during the massive “Big Dig”—that many say was “the most reported civil project in the world” as Massachusetts took Interstate’s 93 and 90 from above ground to 50 feet below ground, and under water. But the Big Dig, says CEO David Cerchie of VersaFlex, “is how we got our first big break that put us on the map.” [text_ad] He explains that the elevated six-lane highway “was designed in 1959 to handle about 60,000 cars a day and now was trying to support more than 200,000 and it was a mess.” Staggering Numbers, Historic Engineering The Big Dig, comparable to the building of the Panama Canal and the English Channel Tunnel, excavated 16 million cubic yards of soil in building the underground 8–10 lane expressway that used 3.8 million yards of concrete—that’s about 2,400 acres of dirt a foot thick. Today, the old site of the aboveground expressway has created more than 45 public parks, downtown redevelopment, and new retail, commercial, and housing developments. But the building of any tunnel underwater presents major challenges in keeping water out during the construction process. Cerchie says at that time, their company had just formulated a dual spray system of their two-part polyurea waterproofing product “that had exceptional resilience underwater.” “We did a trial for the Boston highway project and they were so impressed and fell in love with it, so we ended up doing 4 million square feet of waterproofing.” Cerchie describes the product as perfect for potable water projects as “all the molecules tie up with each other in this two part chemistry we use, so there is no environmental damage, no leaching to give off something you don’t want. Plus, it cures regardless of temperature which makes it perfect for subzero projects such as cold climate conditions and for use in freezers, for example.” Because of their versatility and flexibility, the VersaFlex coatings and linings “can save people money when they think they have to scrap a water holding container, even steel ones.” “When the bottoms have rusted out, people think ‘we’ll have to replace this tank.’ But we can go in and put down some geotextile, and we’ll coat that, and come up the sidewalls, and even if it’s supposed to be a short-term fix, we’ve had situations where they have gotten 10 more years out of their tank for far less money.” A Solution for Aging Water Tanks Potable water has typically been stored in huge concrete tanks and reservoirs that can hold millions of gallons of water. But freeze-thaw cracks, and the weight of the water itself can cause worsening conditions and what starts out as a hairline, can open to a one-eighth inch wide fissure when a tank is filled with water. In many cases, epoxies are used to act as a waterproof coating—but lacking flexibility, they are a short-term solution. New technologies in the form of polyurea coatings and linings like VersaFlex offer strength and flexibility, which is exactly why the Redstone Arsenal Public Works Department of Redstone, AL, selected VersaFlex for their more than half-century old water tank. According to officials, the 5-million gallon concrete tank, built in 1941 during WWII to supply fire suppression, also supplies back-up drinking water supply for the Huntsville, AL Army base population. But over its long lifetime, the water tank had developed hundreds of cracks and leaks, and was losing water in appreciable amounts, leaving the Army base with the decision to either repair or demolish the tank. Brian Burgess, vice president of Contracting and Materials (C&M) explains the deterioration, and describes the solutions used in repair. “The tank had cracked quite a bit and was losing a significant amount of treated drinking water which is [now] more expensive.” Although the Arsenal “had attempted to use different types of liners over the years, it wasn’t working.” Since the Army base had recently rehabbed a nearby water storage pond with the VersaFlex polyurea product, they thought this would be a solution that could save the existing big tank, plus save the expense of building a new one. Burgess was sold on the ease of use, and reduction of down time when a tank has to be out of service. “The VersaFlex polyurea sets up in seconds and [the tank] can be put back into service as fast as an hour,” he says. “It can take days for epoxy to cure enough to do the same. The time saved can provide tremendous savings to a facility.” After an application of concrete grout to the cracks that were in excess of an eighth inch, C&M then primed the surfaces with the VF 20 primer, then applied 80–100 mils of Aqua Vers 405 polyurea, first to the walls. Next, the tank floor was cleaned and primed and the final coating applied, making the entire restoration a two-month project. Cerchie says the application involves two lines of different agents “that are heated in individual lines to lower viscosity and then they come out together at the end of the spray gun where it cures instantly upon application. If you didn’t do it this way it would already be starting to cure.” But the fast cure is what makes the product ideal in the eyes of engineers, says Cerchie. “When we get in front of them they come away from the encounter and are sold because they realize with this [product] there is another solution available. Many coatings are restricted to size, but ours is approved without restriction. We have ASTM testing standards and developed ISO lab-certified products.” While it is a cost-effective solution for potable water containment, it is also used across diverse commercial and industrial markets for which Cerchie says it has “potentially thousands of uses.” He adds this includes other water-related applications, too. Sensitive to environmental preservation, Cerchie says the product is being used in green roofing “to keep water from leaking into the building, and also as a containment for frack water, which is nasty stuff, and it keeps it away from the watershed. “It is also used extensively in the Marcellus shale region of eastern Ohio to protect big water during mining. These polyurea systems can be used to protect the environment from the inevitable.”

He explains that the elevated six-lane highway “was designed in 1959 to handle about 60,000 cars a day and now was trying to support more than 200,000 and it was a mess.”

Staggering Numbers, Historic Engineering
The Big Dig, comparable to the building of the Panama Canal and the English Channel Tunnel, excavated 16 million cubic yards of soil in building the underground 8–10 lane expressway that used 3.8 million yards of concrete—that’s about 2,400 acres of dirt a foot thick. Today, the old site of the aboveground expressway has created more than 45 public parks, downtown redevelopment, and new retail, commercial, and housing developments.

But the building of any tunnel underwater presents major challenges in keeping water out during the construction process. Cerchie says at that time, their company had just formulated a dual spray system of their two-part polyurea waterproofing product “that had exceptional resilience underwater.”

“We did a trial for the Boston highway project and they were so impressed and fell in love with it, so we ended up doing 4 million square feet of waterproofing.”

Cerchie describes the product as perfect for potable water projects as “all the molecules tie up with each other in this two part chemistry we use, so there is no environmental damage, no leaching to give off something you don’t want. Plus, it cures regardless of temperature which makes it perfect for subzero projects such as cold climate conditions and for use in freezers, for example.”

Because of their versatility and flexibility, the VersaFlex coatings and linings “can save people money when they think they have to scrap a water holding container, even steel ones.”

“When the bottoms have rusted out, people think ‘we’ll have to replace this tank.’ But we can go in and put down some geotextile, and we’ll coat that, and come up the sidewalls, and even if it’s supposed to be a short-term fix, we’ve had situations where they have gotten 10 more years out of their tank for far less money.”

A Solution for Aging Water Tanks
Potable water has typically been stored in huge concrete tanks and reservoirs that can hold millions of gallons of water. But freeze-thaw cracks, and the weight of the water itself can cause worsening conditions and what starts out as a hairline, can open to a one-eighth inch wide fissure when a tank is filled with water.

In many cases, epoxies are used to act as a waterproof coating—but lacking flexibility, they are a short-term solution.

New technologies in the form of polyurea coatings and linings like VersaFlex offer strength and flexibility, which is exactly why the Redstone Arsenal Public Works Department of Redstone, AL, selected VersaFlex for their more than half-century old water tank.

According to officials, the 5-million gallon concrete tank, built in 1941 during WWII to supply fire suppression, also supplies back-up drinking water supply for the Huntsville, AL Army base population. But over its long lifetime, the water tank had developed hundreds of cracks and leaks, and was losing water in appreciable amounts, leaving the Army base with the decision to either repair or demolish the tank.

Brian Burgess, vice president of Contracting and Materials (C&M) explains the deterioration, and describes the solutions used in repair.

“The tank had cracked quite a bit and was losing a significant amount of treated drinking water which is [now] more expensive.” Although the Arsenal “had attempted to use different types of liners over the years, it wasn’t working.”

Since the Army base had recently rehabbed a nearby water storage pond with the VersaFlex polyurea product, they thought this would be a solution that could save the existing big tank, plus save the expense of building a new one. Burgess was sold on the ease of use, and reduction of down time when a tank has to be out of service.

“The VersaFlex polyurea sets up in seconds and [the tank] can be put back into service as fast as an hour,” he says. “It can take days for epoxy to cure enough to do the same. The time saved can provide tremendous savings to a facility.”

After an application of concrete grout to the cracks that were in excess of an eighth inch, C&M then primed the surfaces with the VF 20 primer, then applied 80–100 mils of Aqua Vers 405 polyurea, first to the walls. Next, the tank floor was cleaned and primed and the final coating applied, making the entire restoration a two-month project.

Cerchie says the application involves two lines of different agents “that are heated in individual lines to lower viscosity and then they come out together at the end of the spray gun where it cures instantly upon application. If you didn’t do it this way it would already be starting to cure.”

But the fast cure is what makes the product ideal in the eyes of engineers, says Cerchie.

“When we get in front of them they come away from the encounter and are sold because they realize with this [product] there is another solution available. Many coatings are restricted to size, but ours is approved without restriction. We have ASTM testing standards and developed ISO lab-certified products.”

While it is a cost-effective solution for potable water containment, it is also used across diverse commercial and industrial markets for which Cerchie says it has “potentially thousands of uses.” He adds this includes other water-related applications, too. Sensitive to environmental preservation, Cerchie says the product is being used in green roofing “to keep water from leaking into the building, and also as a containment for frack water, which is nasty stuff, and it keeps it away from the watershed.

“It is also used extensively in the Marcellus shale region of eastern Ohio to protect big water during mining. These polyurea systems can be used to protect the environment from the inevitable.”
About the Author

Barbara Hesselgrave

Barbara Hesselgrave is a writer specializing in environmental topics.

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