Tuesday, August 31, 2021


Many of the hydropower pumped storage units are over a decade old and need to be rehabilitated to improve their life, capacity, efficiency, or resolve groundwater leaking in (infiltration) or out (exfiltration) because of cracks and leaks. If these issues are not addressed, they can result in fines from the EPA, FERC, and communities, as well as expensive, time-consuming repairs. More facilities use advanced waterproofing methods such as polyurea coatings or linings to optimize their hydropower pumped storage and fix groundwater leakage problems.


Water loss can occur in old pumped storage stations due to various reasons, including ground movement or daily or seasonal temperature fluctuations that cause expansion/ contraction. This phenomenon is often called freeze-thaw.

Harsh winters can cause asphalt damage that can result in repaving projects that cost millions of dollars. Damage often occurs in areas where the ice is attached directly to asphalt. During the thaw, it can cause damage to asphalt by dragging chunks of asphalt to the bottom. These large pieces and chunks of asphalt can cause damage to the structure and more costly maintenance.

Concrete and asphalt can move several inches due to the weight of water in pumped-storage stations. Tiny cracks can result in cracks up to 1/8 inch wide when water is added to drained storage stations.

Whatever the reason, pumps storage stations can lose hundreds upon hundreds of gallons per minute because of leakage. This reduces their effectiveness in storing power and raises the cost.

Traditional pumped storage station maintenance repairs are made with various materials, including tar and emulsified rubber. These traditional coatings are not flexible enough to move or flex with concrete and asphalt and can crack. They do not combine the ability to waterproof concrete or asphalt and bridge current and future cracks.


Water facility managers are now turning to polyurea linings and coatings. These are the only protective coatings that can withstand the expansion and contraction cycles in substrates such as concrete, asphalt, and stainless steel. Advanced polyurea coatings have high tensile strengths and the ability to stretch up to 400 percent.

ArmorThane manufactures protective coatings and waterproof membranes applied to U.S. reservoirs, bridges, tunnels, highways, railways, and other markets.

While other sealers and epoxies may have cracked and opened up in a short time, pure polyurea remains seamless and waterproof. 

The spray-applied coating forms a seamless, waterproof, and durable protective liner that stops leaks and strengthens the integrity of the storage structure. It can withstand years of freeze-thaw cycles, large temperature variations, and humidity changes. 


The polyurea coatings can easily be applied to asphalt or similar substrates with minimal surface preparation and crack repair. Another method is to spray the polyurea to geotextile fabric that's placed above the substrate. This results in a monolithic, strong, flexible, seamless liner. The same material makes the seamless waterproof membrane for the geotextile fabric to fuse the panels.

Pre-sprayed panels can be used to repair cracks or surface damage. However, membranes can have different adhesion requirements.

Polyurea coatings can be applied using either method. They have superior physical properties such as high crack bridging, hardness, and hardness. This creates an industrial liner that protects and strengthens pump storage areas.

Polyurea bridges crack and fill in the gaps when the substrate cracks or moves. Polyurea works with the substrate to extend its waterproof integrity without affecting the liner.

Only minimal preparation is needed when the concrete or asphalt substrate is being applied. Some substrates require primers and preparation. Polyurea is fast setting and curing so that it can save you thousands of dollars every hour.

Asphalt repairs can take up to a week to inspect, cut, patch, seal, and cure. Polyurea can be applied in about one hour, and the area can be returned to service within an hour.



A pump storage facility in the United States spent $15 million eight years ago to repair an asphalt-lined reservoir. Yet, it was still losing hundreds upon a minute of water. The life expectancy of the asphalt resurfacing was expected to last 15 to 20 years. However, the harsh environmental conditions caused it to last less than 10. An estimated $25 million is needed for another repaving in 2018.

The facility tested two areas of asphalt sloped sidewalls to determine the best waterproof coating. One area was coated with a pre-sprayed polyurea membrane, and another was applied directly to asphalt spray.

Applied polyurea membrane panels.

Particular attention was paid to the areas tested for pumped storage reservoirs. The test revealed no ice was visible in the polyurea test areas during the third winter season, even though the ice had been frozen around the entire 2.5-mile perimeter. Polyurea was able to remove the ice from its reservoir's rim naturally.

The facility plans to cover an additional 40,000 sq. feet in spring due to the success of its polyurea testing areas. If you have a similar project and would like to know how ArmorThane could help you, click here and contact them today.


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