HOW DO YOU REPAIR CONCRETE?

 

Concrete surfaces can be found in a wide range of situations, and they are frequently chosen not only for their strength but also for their ease of installation. Concrete may be exposed to harsh conditions such as year-round exposure to weather and UV light, as well as heavy use in workplaces where foot traffic and machinery can cause damage.

 

Concrete floors can be found in warehouses, factories, workshops, garage forecourts, car parks, loading bays, and children's play areas at schools and parks.

 

Concrete walls can be used as extensions on commercial and industrial buildings, but they can also be used as low walls where paths may cut through the higher ground, such as outside areas and public buildings, to provide a gentler approach for foot traffic.

 

Concrete is also used to build steps that connect outdoor areas of varying heights and slopes that make these areas accessible to wheelchair users.

 

Follow the simple seven-step process outlined below by Concrete Contractor Omaha to ensure that concrete repair work is done safely, to a high standard, and with long-lasting results.

 

Before You Begin

At the start of all projects, make sure to: 

• Use only clean potable water 
• Keep tools clean and well-maintained

 

Things not to do when repairing concrete:

• Never contaminate the mixture with other chemicals
• Never mix powders from different products
• Never add more water than recommended
• Never mix and apply the product in direct sunlight.

 

Step 1: Substrate Preparation

Depending on the size of the affected area, mark the defective concrete and then remove it.

 

A hammer and chisel will most likely suffice for minor patch repairs.

 

For slightly larger areas, use a hammer drill; for even larger areas, a high-pressure water jet may be required.

 

Remove concrete to a depth of 155mm behind the main bars, with a cutting angle of 90° to avoid undercutting and a maximum of 135° to reduce debonding around edges.

 

Before proceeding, ensure that the substrate is sound and no loose material; notify a supervisor immediately if any cracks in the substrate.

 

Step 2: Reinforcement Preparation

Remove all loose material, including tie wires, mortar/concrete, rust/scale, and any other loose material.

There are three methods of removal:

• Steel wire brush or hand/power tools – this method is only applicable in carbonated concrete and under environmental constraints where techniques two and three are ineffective.
• Abrasive blast cleaning – if chlorides are present, water should be used to clean the reinforcement.
• Water jetting at high pressure – a minimum of 1,100 bar

 

Step 3: Reinforcement Corrosion Protection

Allow the first coat to harden before applying the second coat in two 1mm thick layers.

 

Allow the application to dry completely before applying repair mortar.

 

Corrosion protection can be applied with a hopper spray for large areas or with brushes for smaller areas. In this case, use two brushes at the same time to ensure full application behind the bars.

 

Step 4: Bonding Primer

Before wiping away excess water, wet the substrate, preferably with a sponge for small areas and air pressure for larger areas.

Use a brush or a hopper gun to apply the primer. To ensure even application behind the bars, point the gun at different angles on the surface.

 

 

Step 5: Repair Application

If no bonding primer was used, wet the substrate as directed in step four.

 

When repairing by hand, use a trowel and/or your hand to press the repair mortar firmly into the repair area. If the application depth exceeds the maximum layer thickness of the product, apply a second layer after the first layer has dried.

 

Finish with a trowel after profiling the surface. For best results, use a wooden or PVC trowel to finish. Do not splatter any more water on the surface.

 

When repairing by spray, keep the nozzle 200mm to 500mm away from the surface.

 

For best results, finish with a wooden or PVC trowel. Ensure that any gaps behind the bars are filled. If a second layer is necessary, the surface should not be too smooth.

 

Step 6: Mortar Smoothing

Wet and clean the surface with water to prepare it (180 bar). Then, using a toothed trowel, smooth the mortar vertically. The trowel should be held at a 45-degree angle to the surface.

Apply a second layer once the first layer has hardened.

Smooth the surface with a wooden trowel after the product has set (this can take anywhere from 25 minutes to 4 hours).

 

Step 7: Following Application

Curing the repair will protect it from frost, wind, rain, and sun.

To avoid surface cracking, apply as soon as possible after application.

Curing of other membranes can be done with plastic sheeting, fabric, and water.

If no additional coating is to be applied, an approved curing agent could be used instead.