Understanding Concrete Cancer And Your Options - Jamesons | Strata Managers Sydney

Understanding Concrete Cancer And Your Options

16 May 2019

All types of walls can have cracks in them and, often, they are a mere aesthetic problem rather than a danger to the structural integrity of a building. However, in the case of concrete spalling – the visible cracks caused by concrete cancer – there’s more on the line than just looks. Today, we’ll equip you with all the info you need to identify concrete cancer and take the right steps when dealing with it.

What is concrete cancer?

To reinforce concrete buildings, the material is usually poured around a supporting iron or steel bars and mesh. While this usually keeps the structure of a building up, this combination of materials can also cause the development of concrete cancer, especially in buildings with inadequate waterproofing or building defects.

In these cases, the metal structure inside the concrete starts to rust, which sets off a chain reaction. The metal structure starts expanding and replacing the concrete, causing spalling and, in a vicious cycle, exposing more and more of the reinforcing structure to the air and water that set of the rusting process in the first place.

The signs of concrete cancer

There are a few tell-tale signs of concrete cancer, with the most obvious one being the spalling itself. But already before visible cracks form, crumbling concrete, leaks in internal walls, expanding walls, bubbling concrete render and rust stains can clue you in to what is going on inside the walls.

Your options

There are three main strategies to tackle the issue:

  1. Polymer modified repair system: If the main issue is concrete carbonation, the best option is to implement a polymer modified repair system, which involves reinforcing the steel with a polymer modified material to protect it from further corrosion.
  2. Electrochemical treatment: This is the more complex option, but it works best for buildings where chloride contamination is causing the damage, which is frequently the case in coastal areas.
  3. Replacement and removal: This can work both with very extensive and limited damage. If there isn’t a systemic problem with corrosion, the corroded steel can simply be replaced, or, if for example an entire floor is affected, non-load bearing columns and walls can be removed without replacement and others can be replaced.

How much does it cost?

Unfortunately, repairing spalling – especially in structurally critical areas – can be complicated and costly in certain situations. For example, a severely damaged balcony can cost anything from $8,000 to $30,000 to fix or replace. However, time is a deciding factor in how much you will need to spend. It will also pay off to work with a professional and experienced structural engineer who can help you make the safest and most cost-effective decisions in the long term, preventing any further damage and making sure that the repaired structures will last as long as possible.

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