When designing a concrete structure, engineers are typically concerned about load, service life, and exposure. Exposure is especially important as the entire structure can lose structural integrity if the concrete comes into contact with corrosive agents for extended periods of time. To deal with corrosion, engineers often specify concrete protection either in the form of a spray-on coating or a geosynthetic liner.
In this article, we will discuss the importance of concrete protection, some of the shortcomings of concrete waterproofing coatings, and how to find the best concrete protection solution with AGRU.
The Importance of Concrete Protection
Concrete, although very durable, can fail given time and exposure. For this reason, before starting a project engineers will ask about the expected exposure for the concrete structure to anticipate the kinds of countermeasures they will need to incorporate. If they are creating a structure for municipal wastewater, for instance, then they know that corrosive gases are something they may need to protect the concrete against. Hydrogen sulfide gas (H2S) generated from anaerobic decomposition can cause microbial corrosion when microorganisms convert the condensed H2S gas into sulfuric acid (H2SO4). In time, structures exposed to corrosion can fail.
Although potable water tanks do not come into contact with all the media found in wastewater, they are still susceptible to degradation from leeching, carbonation, and chlorides. In addition, these structures are vulnerable to leakage near piping joints. To prevent corrosion and degradation or exfiltration/infiltration, operators often add concrete protective coatings or liners to act as an ultralow permeability layer between the concrete and the contained media. These systems also help to minimize bacterial growth as their smooth surfaces limit the ability of the bacteria to attach to the surface. Additionally, they can also improve the flow characteristics of piping and transmission systems.
By adding a concrete protective layer on a concrete structure, engineers can reduce the frequency of maintenance, extend the expected lifetime, and improve overall operational efficiency. But not all forms of concrete protection work the same way.
The Limitations of Spray-on Coatings for Concrete Protection
In some cases, spray-on coatings aren’t quite the right solution. While a spray-on concrete protective coating may work well in a static tank, they begin to face limitations as the expected service life of the construction increases and if engineers anticipate groundwater backpressure. For long-lasting concrete structures, the formation of cracks is inevitable. When cracks form, they can rupture the protective coating, causing the contents to come into contact with the concrete.
Cracks can also form from the exterior surface, creating a pathway for groundwater backpressure that can push the coating off the wall. Engineers searching for a durable, long-lasting solution often turn to concrete protective liners.
Finding the Best Solution with the Plastics Experts
Concrete protective liners (CPL) come in a variety of materials. The type manufactured by AGRU is most often made with polyethylene, a thermoplastic that offers excellent chemical resistance (from pH 1.0 up to pH 14), durability, and flexibility. CPL offers numerous benefits over alternative products, including improved thickness and durability, which enables the liner to function with a longer service life and with fewer maintenance requirements.
AGRU produces several CPL options, but choosing the right one does not have to be time consuming. As the Plastics Experts, AGRU is committed to helping its customers select the optimal, most cost-effective plastics solution for every project. For example, if you are rehabilitating a potable water concrete storage tank, then a product like AGRU HYDROCLICK® would likely be recommended. HydroClick is specially designed for rehabilitation projects in need of concrete protection, offering an easy-to-install design.
For new concrete construction projects with CPL, AGRU-ULTRA GRIP® is the product of choice. Ultra Grip is the latest incarnation of AGRU’s industry leading Sure Grip CPL product. For engineers working on projects with high backpressure, Ultra Grip is second to none and offers a pullout resistance of up to 820 kN/m2, multiple resin choices, and sheets of up to 10 feet in width and 5 mm in thickness. Ultra Grip is manufactured with a patented V-shape anchor that—as its name suggests—allows the liner to grip into the concrete structure.