Effective Concrete Repair Techniques
What Causes Concrete Cracks?
Concrete cracks can be caused by a variety of factors, including:
Shrinkage. As concrete dries and cures, it naturally shrinks. This can cause cracks to form, especially in large slabs of concrete.
Temperature changes. Concrete expands and contracts with changes in temperature, which can cause cracks to form.
Settlement. Concrete can crack if the ground beneath it settles or shifts, putting pressure on the concrete.
Poor construction. Incorrectly mixed concrete or improper placement and curing can lead to cracks.
Heavy loads. Concrete can crack under the weight of heavy loads, such as vehicles or heavy machinery.
Freeze-thaw cycles. Repeated freezing and thawing can cause the water in concrete to expand and contract, leading to cracks.
Chemical reactions. Certain chemicals, such as salt, can react with the concrete and cause it to crack.
Tree roots. Tree roots can grow under concrete and cause it to crack as the roots grow and expand.
Post-Tensioning effects can also create concrete cracks, especially to perimeters of buildings.
However engaging a structural engineer is the best way to diagnose the causation of concrete cracks, they can survey the building or structure and undertake other tests to most effectively understand the underlying factors and risks.
Types of Concrete Repair Methods?
There are several methods for repairing concrete, including:
Surface coatings: Applying a protective coating such as an cementitious, epoxy or polyurethane, to the surface of the concrete can protect it from damage and make the concrete surface look better. Honey combing and air gaps are common, so can effectively present better.
Patching: This is a common method used to repair small areas of damaged concrete. It involves cleaning the area, applying a bonding agent, and filling the damaged area with new concrete.
Epoxy injection: This method involves injecting epoxy into the damaged area to fill cracks and bond the concrete together.
Flowable Grouts: This involves excavating failed concrete cross sectional area, and placing a flowable grout mixture into the damaged area to fill voids and stabilise the concrete. This may be injected or gravity fed.
Reinforcing: Carbon Fibre reinforcement is often used when excessive loads and concrete cracks start to appear, or additional loads are planned and structures need strengthening.
Overall, the best method for repairing concrete will depend on the extent of the damage and the location of the concrete. It's important to consult with a structural engineer to determine the best approach for your specific situation, especially where ongoing movement makes concrete repairs ineffective.