Concrete Repairs

Structural Repairs Crack Stitching Lateral Restraints Lintel Repair and Replacement Concrete Repairs Timber Repairs

Concrete buildings and components that keep the concrete stabile such as lintels are durable, however, even the strongest of structures will deteriorate over time and will need repair. There are a number of reasons concrete can deteriorate such as structural damage, corrosion, water infiltration and many more.

As part of our concrete repairs service, our team at Timberwise are fully trained to provide the most effective solution to your specific concrete related problem. Severe concrete damage will more than likely need a qualified structural repairs engineer to inspect and determine what is causing the problem.

What Causes Cracks in Concrete?

There are several key issues that can cause damage to concrete. The most well known causes of concrete damage are carbonation and chlorides. The faster the chlorides and carbon dioxide affect the concrete the faster the layer surrounding the reinforced bars will be destroyed and this will then start the corrosion process. Detailed explanations of these processes are listed down below:

Carbonation

Due to the porous nature of concrete, carbon dioxide in the air can penetrate it causing damage. The soluble alkalis and calcium hydroxide give concrete a PH of around 12.5 and when carbonation begins the calcium hydroxide reacts with the carbon dioxide which in turn lowers the pH of the concrete and this can leave it at risk of deterioration.

Carbonation starts on the surface of the concrete, but over time it penetrates into the pores of the concrete causing deterioration, although this doesn’t happen if the concrete is fully submerged in water. The carbonation process can have a detrimental effect on the protection that once existed for the steel bar within the concrete, and that makes the material very susceptible to corrosion. Once the carbonation process begins the protective environment which once existed for the steel bar is reduced allowing it to be susceptible to corrosion in the event that there is any moisture present.

Chlorides

Natural aggregates, water and salt all cause chlorides to be released into the concrete and these can lead to the accelerated corrosion of the steel bars in areas where this occurs.

Freeze & Thaw

During cold temperatures, water that enters into the porous areas of the concrete can freeze. This can cause it to expand and put additional outward pressure on the material.

Sulphate Attack

Properties in the aggregates and cement can cause a chemical reaction and this can result in a breakdown of the concrete.

Concrete Repair and Maintenance

The first step to repairing the concrete damage is to carry out a full inspection of the building and assess the condition of the concrete as well as determine if there are any defects present in the concrete. This can be deduced by using a metal hammer to tap the surface. Sub-surface deterioration will give a lower-pitched “hollow” sound compared to a high-pitched sound given by a good quality concrete.

Low-level voltage can be produced by corrosion. As a result, half-cell testing is conducted on the reinforcing steel to reveal the electrical potential. The depth of carbonation, chloride content, core sample testing and compressive strength are all tested and conducted.

Once the inspection has been carried out the repairs for damaged concrete can be implemented. Concrete repairs are generally carried out similarly across all companies.

This involves cleaning the concrete surface so there is no loose material such as concrete flakes or any existing dust. In some cases, a chisel or sledgehammer may be used.

The loose material will be removed from where the crack in the concrete is located. To rebuild the defective area a suitable repair mortar can be inserted.

Once the concrete repairs have been completed, protection must be made around the surrounding areas to avoid further deterioration in the future. This can be from adding protection coats to limit moisture penetrating through the concrete.

Other improvements that can be made are to the drainage channels to avoid dampness on concrete floors. It is important to be aware that any inappropriate use of the protective coating can cause further deterioration to the concrete as moisture can, in some cases, become trapped.