Repair mortar (RM) and repair concrete (RC) consist of cement-bound mortar or concrete, which may be polymer-modified or not, and, where necessary, a bonding agent and levelling filler or scratch coating. The concrete repair systems are applied manually or by concreting.

Sprayed mortar (SRM) and sprayed concrete (SRC) consist of cementitious mortar or concrete, which may be polymer-modified or not, applied by spraying. The abbreviations SRM and SRC stand for "sprayable repair mortar" and "sprayable repair concrete".

The concrete repair systems RM/RC and SRM/SRC are used for repairing concrete structures. Examples include filling locally limited interstices to restore the original surface of the structure (reprofiling) or large-area applications, e.g. to increase the concrete cover of the reinforcement, to produce a surface profile or to strengthen the concrete cross-section.

A distinction is made between concrete repair systems RM/RC that can only be applied to horizontal or slightly inclined surfaces under non-dynamic loading (application case I) and concrete repair systems that can be applied to surfaces at any inclination angle under dynamic (e.g. caps, bridge soffits) or non-dynamic (e.g. retaining walls, abutments) loading (application case II).

Spray mortar/concrete is not suitable as a concrete repair system on horizontal, slightly inclined surfaces that have to be sprayed from above (e.g. top surfaces of roadway slabs on bridges). With machine application, a distinction is made between dry and wet spraying methods.

The 'Additional technical terms of contract for the repair of concrete structures in hydraulic engineering' (Zusätzliche Technische Vertragsbedingungen für die Instandsetzung der Betonbauteile von Wasserbauwerken, ZTV-W LB 219) provide for a classification of the existing structures or sections to be repaired into age classes based on their properties at the time of repair. The concrete repair systems RM/RC or the sprayed mortar/concrete SRM/SRC are assigned to concrete age classes according to the existing properties:

• RM-A4, RM-A5, RC-A4, RC-A5 or
• SRM-A2, SRM-A3, SRM-A4, SRM-A5, SRC-A2, SRC-A3, SRC-A4, SRC-A5

Polymer concrete (PRC) consists of plastic-bonded concrete and, where required, a bonding agent, which is applied manually. The abbreviation stands for "polymer repair concrete".

Polymer concrete is used for repairing concrete structures. Examples include filling locally limited interstices to restore the original surface of the structure (reprofiling).

The 'Additional technical terms of contract and guidelines for engineering structures' (Zusätzliche Technische Vertragsbedingungen und Richtlinien für Ingenieurbauten, ZTV-ING) do not provide for a classification of the existing structures or sections to be repaired into concrete age classes based on their properties at the time of repair. Polymer concrete can generally be assigned to the concrete age class A4 based on the existing properties.

Regulatory framework

DIBt prepares evaluations of the fitness for use of repair mortars and concretes in the area of transport infrastructure construction. The evaluations provide independent validation of additional information that cannot be stated in the declaration of performance.

It would also be possible to issue an ETA instead of an evaluation, however, there are no European Assessment Documents (EADs) for repair mortars and concretes as yet.

In accordance with the ZTV-ING and ZTV-W LB 219, the evaluations serve as 'verifiable confirmation' (prüffähige Bescheinigung) and are recognised as equivalent to project-specific verifications when they fully correspond to the construction specifications. The Notes on ZTV-ING (Hinweise zu den ZTV-ING) – Part 3 – Section 4 and the BAWRecommendation 'Repair products – Notes for the expert designer on works-related product characteristics and test methods' (BAWEmpfehlung "Instandsetzungsprodukte – Hinweise für den Sachkundigen Planer zu bauwerksbezogenen Produktmerkmalen und Prüfverfahren") are to be observed to support the construction specifications and the execution of construction work.