Repair of damage with exposed steel reinforcement

Before undertaking any concrete repair, care should be taken to fix props and supports around the location to be repaired, especially in the surroundings of damaged columns and beams.

The following surface preparation is recommended:

Common issues and queries you can face

Step 1

• By using a marker pen, delimit the area of damage.

• Break beyond the delimited area until reaching sound concrete and steel.

• With a jackhammer, saw-cut 2 cm deep in 90° angle the perimeter of breaking, in order to avoid feather edges.

• All weak, damaged and easily removable concrete should be chipped away. If the re-bars are only partially exposed after all unsound concrete is removed, it may not be necessary to remove additional concrete to expose the full circumference of the reinforcement. When the exposed reinforcement steel has a loose wrap, corrosion or is not well bonded to the surrounding concrete, the concrete removal should continue until a clear space of 15 to 25 mm is created behind the reinforcing steel.

Step 2

• Clean steel reinforcement with mechanical wire-brushing or by sandblasting.

• In case the reinforcing bars are corroded and have lost more than 25% of their diameter, they have to be cut and removed.

Step 3

• In such event, removed steel bars should be replaced with new steel bars of the same diameter either by respecting the overlap length or by welding 100 mm length to the existing steel.

Step 4

• Remove dust by air blowing and wash with clean water to achieve a Surface Saturated Dry (SSD) substrate.

Protection of steel reinforcement against corrosion:

After all necessary preparation, steel reinforcement should be protected against corrosion with a highly alkaline product weberep 370 PF or a zinc rich product that delays the aggressive elements attack steel, like weberep 501 ZRP