The rules governing the reinforced concrete sector, from design to mixing, from degradation diagnostics to its functional restoration, represent a complex and constantly evolving world. AZICHEM, as a manufacturing company, has always had a careful and proactive look towards this world, demonstrating this guideline both as a MEMBER of the Italian UNI regulatory body, and by participating in the UNI technical tables, as well as in allocating an important part of its proceeds for product and system certifications according to nationally and internationally recognized standards. Dealing in depth with the regulatory field is beyond the objectives of this site. However, we can say that great strides on the quality of concrete and restoration systems were made following the adoption of certain European technical standards, which marked a watershed between “unregulated” technologies, therefore open to free interpretation, often approximate, and “regulated” technologies, therefore subject to controls and compliance procedures. Some milestones were the EN 196 – EN 197 standards on the classification and control of cements or EN 206 on the classification and control of concrete. As regards the protection and restoration systems for concrete, a regulatory bulwark was undoubtedly the publication of the standard which marked a watershed between “unregulated” technologies, therefore open to free interpretations, often approximate, and “regulated” technologies, therefore subject to controls and compliance procedures. As regards the protection and restoration systems for concrete, a regulatory bulwark was undoubtedly the publication of the standard UNI EN 1504: “Products and systems for the protection and repair of concrete structures”.

The standard establishes the standard procedures, the indications to optimize the restoration intervention and the request of the minimum performance requirements for the products and systems to be used for a correct conformity assessment. The norm is very complex and articulated and in this section we will give only very short flashes to make it understand its general structure.

The standard is divided into ten parts.

  1. UNI EN 1504-1 Description of the terms and definitions of the standard.
  2. UNI EN 1504-2 Surface protection of concrete.
  3. UNI EN 1504-3 Structural and non-structural repair.
  4. UNI EN 1504-4 Structural bonding.
  5. UNI EN 1504-5 Injection of concrete.
  6. UNI EN 1504-6 Anchoring of steel reinforcement bars.
  7. UNI EN 1504-7 Protection against corrosion of reinforcement.
  8. UNI EN 1504-8 Quality control and conformity assessment.
  9. UNI EN 1504-9 General principles for the use of products and systems.
  10. UNI EN 1504-10 Application on site of products, systems and quality control of works.

The CE marking

The European standard EN 1504 entered into effect in January 2009.

All products used for the repair and protection of concrete must have the CE mark in compliance with the regulations.

The CE mark affixed to the products, compiled according to relevant standards and information, must preferably appear on the mixing (if this is not possible, it must appear on the accompanying label or on the accompanying documents). The CE marking symbol testifies that the product complies, for its specific field of use, with specific performance, precise durability criteria, and stringent safety parameters required by European legislation.

Strength classes of repair mortars

As for restoration mortars, the legislation defines four classes of mortars:

  1. R4 for structural mortars
  2. R3 for structural mortars
  3. R2 for non-structural mortars
  4. R1 for non-structural mortars

The class of belonging of the restoration mortars is defined by the performance characteristics obtained during the test phase; this implies that all the mortars used for restoration work must comply with the minimum requirements required by the standard. For the various classes, a series of fundamental mandatory parameters are established (such as the mechanical compressive strength, the elastic modulus, the adhesion to the substrate, the depth of carbonation, the chloride ion content) and other optional parameters (such as for example thermal compatibility, slip resistance, etc.) To give a very simple and intuitive example, the physical-mechanical characteristic of a mandatory parameter such as compressive strength is identified, according to the class to which it belongs,

  1. R4 Compressive strength: > 45 MPa Structural restoration mortar.
  2. R3 Compressive strength: > 25 MPa Structural restoration mortar.
  3. R2 Compressive strength: > 15 MPa Non-structural restoration mortar.
  4. R1 Compressive strength: > 10 MPa Non-structural restoration mortar.