Identify Concrete Cancer
What is it?
Concrete Cancer is the term given to the corrosion of the steel reinforcing within concrete. Once the steel corrodes it expands causing concrete to spall or break away from the steel. There are many potential causes.
It is important to identify what risks you may be subject to due to your environment. This can vary due to environment, the build quality and the location of the structure.
What are the causes?
The steel reinforcing in concrete requires protection from the Building codes specify the steel reinforcing is covered by at least 50mm of concrete. Some structures require more depending on their use and local conditions. The minimum cover is designed to protect the steel.
When a engineer inspects the steel on a newly constructed building prior to the concrete pour, part of the inspection is to ensure that the steel meets its minimum cover requirements. The building codes pre mid 1980s required that the minimum cover of concrete was only 25mm. There for you will find that the steel reinforcing was much more susceptible to corrosion in buildings constructed before this era.
Cracks from Deflection
Due to environmental factors or others, buildings can move, which can cause cracks to appear.
These seems common in appearence and usually don’t cause much concern. However, often the cracking opens the concrete up to contaminants, which causes the errosion of the steel.
AAR (Alkali aggregate reaction)
AAR is an umbrella term for ASR (Alkali silica reaction) and ACR Alkali Carbonate reaction.
Such problems happen when the aggregates in the concrete react with the cement paste. They can be induced by damp humid conditions in which ASR is very common. ACR is very rare – however it does still pose a risk, which Condok recommends you consult an expert to diagnose.
Hazards with Concrete Cancer
Concrete Cancer presents a hazard to all sorts of structures, and all of those that interact with them. It could create issues of falling hazards, or even structural collapse.
This could manifest into a unique risk of making owners liable. It is therefore very important to address symptoms, otherwise be subject to below risks.
Cracks in balconies, ledges and staircases all are very common, however this can in fact be a very serious indicator of Concrete Cancer. Serious enough cracking can therefore mean that concrete can fall and be a falling hazard to anyone below.
Collapse of structure
Depending on the type of structure, Concrete Cancer might pose a structural threat if not addressed. Condok reguarly work with structural engineers with structures that have damage to load bearing concrete.
If you want to see how to best identify Concrete Cancer, then see our article on how to see the key symptoms of concrete damage, and what the recommended course of action is
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