All about Concrete Cancer
Last Updated May 14, 2013 · Written by Jaclyn Fitzgerald
Concrete is one of the most common building materials in use today and chances are that you will find in just about any home or building. However, concrete isn’t a “set and forget” option as it can be prone to concrete cancer if it is not laid correctly and this can be a serious problem, necessitating immediate repair. Here’s what you need to know.
What is Concrete Cancer?
Concrete cancer is a serious problem that occurs within concrete and it is caused by the steel reinforcing inside the concrete rusting. As the steel reinforcing rusts, it expands, causing the concrete around the steel to be displaced. As the concrete becomes more displaced, more water gets into the steel, causing more rusting and the problem gets worse. The expansion of the steel causes the concrete to delaminate, and results in spalling. Spalling is where the concrete initially cracks, and then starts to break away. While spalled concrete looks terrible, it can also be dangerous as pieces of concrete fall off and possibly hit people underneath. Spalling also weakens the strength of the concrete.
Concrete cancer can start in a number of ways including using poorly treated reinforcing steel when the concrete is poured, having the ends of the reinforcing too close to the surface so that water can get to it, using incompatible metals (this causes a reaction), and having fractures in the concrete.
Treating Concrete Cancer
If you suspect that you have concrete cancer in any form, it is important that you get treatment as soon as possible otherwise the problems will only get worse. Treatment needs to be done by qualified professionals as poor treatment will only hide and delay the problem. It is not enough to just render over the concrete to hide the rusting steel, as the rusting process will just continue underneath, causing further displacement of the concrete and even necessitating replacement of the reinforcing steel altogether.
Rather, the cause of the concrete cancer needs to be appropriately identified before a fix can be applied. Once the cause is identified repairs can start, and one excellent method of repair is to remove all drummy and flaking concrete, removing all rust from the reinforcing steel, apply anti corrosives to the steel, and then applying a fresh render so that the original look of the concrete is restored. Waterproofing can also be applied as necessary. By doing this, you can repair the areas of concrete that are damaged rather than having to replace the whole wall.
Another way of treating concrete cancer is to repair all minor cracks and damage to your concrete as soon as you notice them. This is especially important in exposed areas as water getting into the concrete through the cracks will cause the problem to worsen extremely rapidly.