Principle 3 - Concrete Restoration

One of the most important principles within part 9 of EN 1504 is Principle 3: the restoration of damaged concrete. The selection of the appropriate method of replacing and restoring concrete depends on numerous parameters, though the two of the most important considerations are the extent of the damage and the congestion of rebar. 

Localised Repairs

Traditionally the localised repair of concrete defects and damage has been undertaken using hand-placed repair mortars. Komerco provides an extensive range of pre-batched, hand-applied repair mortars from the MasterEmaco and Sika MonoTop brands. These pre-bagged concrete repair mortars have consistently been at the forefront of the search to provide cost-effective, long-term solutions to localised repairs. 

The European standard defines 4 classes of repair mortar: R4, R3, R2 and R1. These are then divided between structural and non-structural repairs, i.e. those applications where load transfer has to be considered in the design of the repair specification, or alternatively for cosmetic works. Furthermore, the standard classifies the repair products for each type of application, ensuring that the repair mortar is adapted to the quality of the parent concrete.

The current choice of products depends on ease, type and field of application. Komerco offers a broad range of repair mortars, customised for structural and non-structural repair for trafficable, vertical and overhead application. Our Concrete Repair Product Selection Table can be used to choose the most suitable product for your requirements. Though an overview by class can be found below:

• Class R4
• Sika MonoTop 612 N
• Sika MonoTop 412 NFG
• MasterEmaco S 5440 CI 
• MasterEmaco S 5400 CI 
• MasterEmaco S 902
• MasterEmaco T 545
• Class R3
• Sika MonoTop 352 NFG
• Sika MonoTop 723 N 
• MasterEmaco S 5300 CI
• Class R2
• Sikadur-43 HE range
• MasterEmaco N 5200 CI 
• Class R1
• Sika MonoTop FC
• MasterEmaco N 5100
• MasterEmaco N 5150

 

Recasting Repairs

Typical recasting repairs, which are also frequently described as pourable or grouting repairs, are employed when whole sections or larger areas of concrete replacement are required. These include the replacement of all, or substantial sections of, concrete bridge parapets and balcony walls etc.

This method is also very useful for complex structural supporting sections, such as cross head beams, piers and column sections, which often present problems with restricted access and congested reinforcement.

The most important criteria for the successful application of this type of product is its flowability and the ability to move around obstructions and heavy reinforcement. Additionally they often have to be poured in relatively thick sections without problems of thermal shrinkage cracking. This is to ensure that they can fill the desired volume and areas completely, despite the restricted access or application points. Finally they must also harden to provide a suitably finished surface, which is tightly closed and free of cracks.

Depending on the size and extent of the required recasting repairs, Komerco offers a broad range of pre-bagged cementitious grouts and high-performance admixtures to meet all requirements. Please refer to the cementitious and epoxy grout product selection guide to find the most suitable product for site requirements.