Concrete Cancer - The Facts
Concrete Cancer and the Facts You Need to Know
There are many environmental factors that can impact concrete structures over a period of time. These environmental factors can cause reinforcement corrosion and spalling of the outer concrete layers. This is often referred to as concrete cancer.
Concrete cancer commonly becomes an issue because the steel reinforcing inside the concrete slab begins to wear and rust. When steel begins to rust it can expand significantly from its original size and this, in turn, causes the concrete that surrounds the steel to expand with it and become loose and flakey. When this flakiness starts to take place it provides an avenue for water to penetrate the concrete and speed up the process.
Because concrete is usually used for structural purposes, if this corrosion or spalling is not rectified quickly it can lead to a very expensive and sometimes dangerous situation and repair bill.
It is very likely that most people would not recognise the signs of concrete cancer until it became quite advanced. Unless you are a structural engineer, or have seen the signs of concrete spalling before, it is very likely that you wouldn’t know what signs to look out for.
Risks Associated with Concrete Spalling / Concrete Cancer
Besides the fact that the look of the concrete is not aesthetically pleasing because of the leeching rust stains and cracking and flaking, concrete cancer can be a significant OH&S issue because people can trip on the loose concrete pieces as they flake and lift, large pieces of concrete can fall from a structure and any passing traffic (cars and people) are at significant risk of serious injury. Other buildings close to the affected area are also at risk of damage depending on the location and the specific circumstances.
Spalling concrete should be repaired quickly because the longer that you leave it, the more damage that will eventuate, the more expensive the fix will be, and the more risk you will experience.
Causes of Concrete Cancer
- Spalling of concrete can begin in a number of ways, and because of a number of circumstances but usually, it is caused by the following:
- Poor quality reinforcing steel that is utilised at the time of slab preparation
- The ends of the reinforcing steel being positioned too close to the surface of the concrete.
- Water penetration seeping into the concrete structure and causing oxidation and rust to occur.
- Heavy load on the structure that causes concrete stress fractures
- General environmental wear and tear of the concrete that then allows water to penetrate the concrete and react with the steel
Signs of Concrete Spalling (Concrete Cancer)
There are a few key signs to keep an eye on and be able to tell if your concrete is needing repair:
- Loose and Flaking concrete
- Cracking concrete
- Rust stains which appear to come from inside the concrete structure
- Bubbling of concrete render
- Leaks that seem to be originating from the roof or internal walls of a structure
Often this can be mistaken for general wear and tear but the problem actually exists inside the concrete itself.