WHAT IS CONCRETE CANCER?
Spalling, or more commonly known as ‘concrete cancer’ is when the steel reinforcing in a concrete slab begins to rust and expand, therefore causing the concrete to become weak, crack, scallop and therefore fall away. The 3 key ingredients (elements) that cause this disease are water, iron and oxygen.
HOW DOES THIS HAPPEN?
- Insufficient concrete to cover the steel reinforcement
- Moisture reaching the internal steel, then combining with carbon dioxide and forming weak carbonic acid – a dissolving acid that breaks down the steel and therefore the supporting structure of the concrete.
IS IT SERIOUS?
Concrete cancer is potentially a serious problem and with most buildings having large expanses of concrete (consider balconies, unhoods and balustrade supporting hobs) that can become displaced, this will result in loss of strength and stability and even dislodged pieces of concrete falling. If not repaired, not only does this problem become a more expensive exercise but one that increases the risk of injury or death through falling concrete, collapsed balconies and the like.
WHAT ARE THE SIGNS TO LOOK OUT FOR?
Just like a disease it isn’t always easy to spot underlying problems from the surface. Though there are some telltale signs that you might find:
- Reddish or brown stains that are next to cracked or bubbled concrete
- Concrete lifting and in a ‘scallop’ look
- Signs of moisture coming through concrete cracks, you might see white crystal-like substance or efflorescence and salt laitance.
‘Scalloping’ can be a sign of spalled concrete.
WHAT CAN BE DONE TO FIX CONCRETE CANCER?
The primary aim of treating concrete cancer is to extend the life and durability of the building. This needs to be done with an appropriate paint system and regular wash down maintenance thereafter to prolong the life of the acrylic coating and remove excessive harmful salt build-up. It is very important that you use a licensed and experienced contractor that employs an effective remedial system which consider the following:
- A proper diagnosis of the problem – a delap report
- Preparation of the existing steel and concrete, possibly needing additional reinforcement to badly corroded steel.
- Environment appropriate construction grouts and supporting products.
- The curing process and specialist coatings required
- Final finished profile looks as good as its original healthy state and is protected from further influences.
If you have concerns about the presence of concrete cancer in your building, you are welcome to give us a call at Leisuretex Property Maintenance Contractors. We are happy to have a chat over the phone or we can arrange for one of our specialists to come and visit you on site.
Leisuretex Painting Contractors
1/3293 Logan Road, Underwood P: 3341 3403
9/443 Golden Four Drive, Tugun P: 1300 852 759
