The 11 Principles & Methods Concerning Concrete Defects

The repair and protection of concrete structures requires relatively complex assessment and design. By introducing and defining the key principles of repair and protection, EN 1504-9 helps owners and construction professionals to fully understand the problems and solutions throughout the different stages of the repair and protection process. The eleven principles of concrete repair and protection according to EN 1504-9 are:

1. Protection Against Ingress

The principle is to keep the concrete dry by reducing its permeability by closing up pores and cracks.

2. Moisture Control

The principle of controlling moisture with acceptable levels using coatings and membranes.

3. Concrete Restoration

Repairing or replacing concrete using a variety of mortars.

4. Structural Strengthening

Replacing lost strength or increasing strength by adding steel, additional reinforced concrete or Fibre Reinforced materials.

5. Increasing Physical Resistance

Replacing lost concrete or providing additional cover and protection.

6. Increasing Resistance to Chemicals

Application of surface protection to improve resistance to chemical attack.

7. Preserving Restoring Passivity

Using mortars or concrete to replace contaminated concrete. Also techniques for re-alkalisation and chloride extraction.

8. Increasing Resistivity

Using coatings and protective systems to reduce the level of moisture in the concrete thereby increasing the electrical resistivity of the concrete and reducing the potential for corrosion.

9. Cathodic Control

Restricting the access of oxygen to the cathodic site by coating the steel.

10. Cathodic Protection

Cathodic protection manages the output of current through the steel to channel currents to specific anodic sites. This may be done using external currents or sacrificial anodes.

11. Control of Anodic Areas

Corrosion of the reinforcement is controlled by a complete film formation, using coatings or corrosion inhibitors.