EN 13529 Protection and Repair of Concrete Structures - Resistance to Severe Chemical Attack

A European standard, “EN 13529 Products and systems for the protection and repair of concrete structures - Test methods - Resistance to severe chemical attack”, describes a method for determining the resistance of surface protection systems to severe chemical attack.

In principle, the resistance of the coating system to severe chemical attack is evaluated by exposing one side of the surface protection system to the test liquid.

A representative, homogeneous sample of the material being tested should be taken as described in EN ISO 15528 Paints, varnishes and raw materials for paints and varnishes - Sampling. The sample should also be examined and prepared as described in EN ISO 1513 Paints and varnishes - Preparation of samples for testing.

Test pieces are concrete slabs with a minimum dimension of 300 mm x 200 mm x 40 mm and are manufactured in accordance with EN 1766 using a test concrete with a maximum aggregate size of 8 mm. The concrete slabs are prepared and stored in accordance with EN 1766. Surface preparation is carried out by sandblasting in accordance with EN 1766. After storage, the concrete slabs must be stored for at least 7 days at a temperature of 21 degrees Celsius plus/minus 2 degrees Celsius and a relative humidity of 60 percent plus/minus 10 percent before coating in accordance with EN 1766.

The test pieces are coated, cured, and stored in accordance with the manufacturer's instructions. The coating thickness must be measured in accordance with EN ISO 2808. It is possible to use slabs without any reinforcement. It is also possible to use slabs with a reinforcement cage, according to the Annex C of prEN 1062-7. A crack-bridging test can then be followed immediately by a test on resistance to severe chemical attack using the same test pieces. If the resistance of the coating over a crack in concrete is to be tested, a bell-type caisson chamber is used. It is placed directly above the notch in the slab.

One or two rings, approximately 20 mm high by 100 mm in diameter, made of non-porous material resistant to test liquid attack, are bonded to the coating with a chemically resistant sealant or adhesive to retain the test liquid. Before the test liquid is poured, the initial hardness of the coating is measured. When using two rings, two different test liquids can be used. The level of the test liquid should reach a height of 10 mm.

The test can be performed with or without 1 bar pressure. When tested with applied pressure, the bell-type caisson chamber is secured and 1 bar air pressure is applied. When tested without pressure, the bonded ring must be covered with a lid to prevent evaporation of the test fluid. The test duration depends on the application specified in prEN 1504-2. Typically, the duration is 1, 3, 7, 28, or 90 days. The standard test temperature is 21 degrees Celsius plus/minus 2 degrees Celsius; other test temperatures can be agreed upon between the parties involved.

Test liquids may be selected from informative Annex A or as agreed upon between the parties involved.

After exposure to chemical attack, the test liquid is removed and the surface is dried with a suitable absorbent or paper cloth and the test pieces are examined by comparison with an unexposed area of ​​the sample:

• Blistering according to ISO 4628-2 standard
• Exfoliation according to ISO 4628-5 standard
• Cracking according to ISO 4628-4 standard
• Optical changes (e.g. colour, gloss) are measured according to ISO 4628-1, and, if possible, adhesion or hardness (Buchholz indentation test according to EN ISO 2815 or Shore hardness according to EN ISO 868, appropriate to the type of coating).
• Penetration of test liquid through the coating.

Coating thickness is measured according to EN ISO 2808. The examination is carried out after 1 hour and 24 hours after removal of the test liquid.

In short, the EN 13529 standard is essential because it defines the performance requirements for coating systems used to protect concrete structures in areas at risk of chemical attack, particularly in environments such as secondary containment areas (dykes), chemical plants, wastewater treatment plants, and similar structures. The main reasons for this standard's importance are:

• Chemical resistance assurance: Protects concrete from deterioration by ensuring that coating systems can withstand exposure to a wide range of chemicals (such as acids, alkalis, solvents, oils).
• Safety and environmental protection: Coatings tested to EN 13529 standard help protect soil, groundwater and the wider environment by preventing chemical leaks from damaged or permeable concrete.
• Structural longevity: Appropriate coatings minimize corrosion and structural deterioration, extending the life of facilities and reducing long-term maintenance costs.
• Compliance and risk management: Provides a recognized benchmark for quality and performance that helps facility owners meet legal and regulatory obligations, especially in industries where chemical containment is critical.
• Standard test procedures: The EN 13529 standard provides a consistent methodology for testing and comparing products, helping manufacturers, specifiers and contractors make informed decisions.

The basic tests defined for coating systems in the EN 13529 standard are:

• Chemical resistance testing: Coatings are exposed to various chemicals (e.g., acids, alkalis, solvents, fuels) for a specified period (typically 28 days). Visual inspection assesses blistering, cracking, and discoloration. Furthermore, adhesion, hardness, or weight change after exposure is assessed, and whether the coating maintains its integrity under chemical stress.
• Adhesion test: Tensile tests are performed before and after chemical exposure according to EN ISO 4624. This test ensures that the coating remains bonded to the concrete substrate.
• Permeability test to liquids: Verifies the permeability of the coating to ensure protection against the ingress of particularly aggressive substances.
• Crack-bridging ability testing: Evaluates the coating's ability to bridge dynamic or static cracks in the substrate. This is particularly important for coatings in structures subject to movement or collapse.
• Temperature resistance testing: Coatings are tested at various temperatures to ensure performance is not compromised in hot or cold environments.
• Abrasion resistance test: This test is important in high-traffic or industrial areas.

To pass the EN 13529 standard, a coating must:

• It should not show significant damage or deterioration after chemical exposure.
• Must maintain minimum bond strength (typically at least 1,5 MPa after exposure).
• It must remain impermeable to liquids.
• It must retain its functionality (e.g. crack bridging) if such features are claimed.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the standard "EN 13529: Products and systems for the protection and repair of concrete structures - Test methods - Resistance to severe chemical attack."