Acid resistant coating for concrete

Concrete in industrial environments

Concrete is a commonly used material in industrial environments due to its durability, strength, and ability to withstand heavy loads. In addition, concrete is often the material of choice because of its relatively low cost. If a structure is needed that covers a large area, the choice of concrete is quickly made. Concrete is commonly used in floors and walls, but also for example in:

• Manure cellars and other agricultural applications
• Water treatment plants and concrete pipes for sewage disposal
• Storage tanks
• Battery rooms
• Reservoirs
• Cellars

Concrete is used in many industrial environments where it may come into contact with various concrete-aggravating liquids.

Concrete and acid resistance

Acid exposure can deteriorate concrete and reduce its durability. The acid type, concentration and contact conditions influence the attack. Identify the substances and exposure conditions before selecting a protective coating. The Concrete Society explains how chemicals can attack concrete.

Different kinds of acids that attack concrete

Some specific forms of acid attack on concrete are distinguished:

Biogenic sulphuric acid

Acid attack of the concrete surface by sulfuric acid produced by bacterial conversion of sulfides to sulfuric acid;

Microbiological nitric acid

This form of acid attack is characterized by sanding and the formation of loose shells on the concrete surface by nitric acid-forming bacteria. Occurs the interior walls of cooling towers for example.

Adhesion by salt, minerals and strong acids

This is the dissolution of cement stone as in acid attack. This attack occurs particularly in fertilizer storage (ammonium salt) and seawater attack (magnesium salt).

Soft water

Soft water can dissolve lime. A concrete surface can be damaged if it is in contact with soft water that is constantly changing. This attack mechanism is similar to acid attack.

Acid resistant coating

To protect concrete from acids in its environment, an acid resistant coating is the best solution. The coating system and surface preparation must be matched to the condition and porosity of the concrete. The coating should deal with the attack of acids, sulfates and other salts as well as the corrosion of reinforcing steel and non-ferrous metals. Which acid resistant coating is best for your situation, depends on the types of acid the concrete comes in to contact with. The table below shows all the coating types along with their overall resistance and the various acids they are not resistant to.

Epoxy coating

Epoxy coating formulations differ in their acid resistance. Check the product-specific resistance data for the acid type, concentration, temperature and exposure time.

Epoxy novolac coating

Novolac epoxy systems are used for chemical-resistant coatings. Suitability must be checked against product-specific resistance data; no coating should be assumed to resist every acid under every condition.

Polyurethane coating

Polyurethane coating formulations differ in their chemical resistance. Confirm suitability against the product-specific data and the conditions of the application.

Choosing the right acid resistant coating for concrete

Choosing an acid-resistant coating depends on several factors, including:

• What specific acids the coating needs to be resistant to
• The concentration of the acids
• The temperature of the area where the exposure will occur
• What other properties the coating must provide alongside acid resistance

The coatings market is changing rapidly. New coatings that are more acid resistant and better for the environment are constantly being developed. adhesives+coatings is up to date with the latest innovations and can help you find the right acid-resistant concrete coating for your application. Please do not hesitate to contact us, we will be more than willing to help you. 

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Frequently asked questions

Why does industrial concrete need an acid-resistant coating?

Concrete can be damaged by acid exposure. A suitable coating protects the surface, but the acid type, concentration, temperature, exposure duration and condition of the concrete determine the appropriate system.

What information is needed to discuss a suitable solution?

Share the substrate, application method, curing conditions, required coating properties and service environment. Include any sustainability targets and required documentation. We can then discuss a suitable formulation and application trial. Discuss your application with us.