Difference Between Epoxy and Polyurethane in Concrete Crack Injections

Apr 15, 2022

Are you looking for a solution to help you repair a crack that has formed in a concrete structure from the inside? This can either be a foundation or a wall. There are two different injection techniques that you can use and two different types of technologies you can utilize. These are known as epoxy resin injections or polyurethane chemical grout injections.

First, let’s talk about what waterproofing injections are. Waterproofing injections are a form of a fluid injection that is injected into cracks in masonry or concrete structures to prevent water penetration. This is important because the penetration of water can cause damage to structures over time, and even lead to erosion and further deterioration of the structure. Waterproofing injections can be injected into walls, chimneys, balconies, basements, and other places where water could be penetrating your structure—and damaging it in the process.

In order for an injection to be considered waterproofing, it has to be able to stop water from penetrating through it for at least ten years. The most popular types of waterproofing injection materials include chemicals like bentonite and polyurethane chemical grouts; there are also non-chemical materials like cementitious grouts and mortars that can be used as well. The most popular types of waterproofing injections today are bentonite-based chemical grout injections

Epoxy Vs Polyurethane in Concrete Crack Injections

Epoxy injection is usually done on dry substrates compared to polyurethane injections which are better solutions for wet or leaking substrates. However, many individuals use epoxy injections as their main solution whenever they need to repair a crack in a structure.

On the other hand, polyurethane injections will usually be used as an alternative when an individual wants to seal a surface that is actively leaking, help prevent moisture from migrating and help protect against things like corrosion and decay related to water. Polyurethane injections are the best solution for sealing cracks in any environment that is actively leaking and/or wet.

Several injection solutions can help solve many types of wall issues. However, you should keep in mind that no solution fits each problem or solves every problem the best way.

Now, let’s take a look and compare the main features of each type of crack injection. We will list out their pros and cons and let you know our recommendations when it comes to their applications.

When it comes to epoxies and polyurethanes, they are both known as chemical resins; however, they have different reactions and different physical characteristics.

Epoxy is a very strong adhesive or glue-like substance that will not expand once it is applied. When you cure epoxy, this creates a very strong bond with the concrete that it is placed on, and it usually results in a repair with highly compressive and tensile strength. Epoxy works in a two-component system. One component is the epoxy resin, and then the second component is known as the hardener. When these components are blended, they will typically be mixed right before the crack injection, as the solution will quickly cure once mixed. Injection epoxies will be chemically cured quickly; however, they will keep hardening over the next few days and weeks.

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