Concrete cancer is a term used to refer to damage occurring to concrete as a result of corroding or rusting of the steel within the reinforced concrete. Contaminants such as chemicals and water penetrating the concrete can cause the underlying steel to rust. As it rusts, the metal is known to expand up to seven times its original size. This displaces the surrounding concrete, causing cracking which in turn exposes even more steel to corrosion. It is self-perpetuating and worsens exponentially as time goes by, hence its apt name 'cancer'. If left unchecked, concrete cancer can severely compromise the structural integrity of any building, warranting costly repairs. However, here are some tips to consider for a much better outcome when you're dealing with concrete cancer.
Detect it in its early stages.
Many people are under the misconception that concrete is invincible. For them, any crack which appears only looks bad and can't possibly cause the building to collapse. However, you should always remain vigilant, and assess the condition of your home or building regularly. Early detection of concrete cancer will save you a lot of money since replacement of the entire reinforcing won't be necessary. There are a number of tell-tale signs that will alert you to the presence of concrete cancer so keep an eye out for them. Such signs include flaking and cracking concrete. Also, look for any rust staining on the concrete without any adjacent metals present. Leaking walls and ceilings are also an important symptom worth noting.
Proper treatment of the steel reinforcing.
Whether you seek the services of concrete contractors or opt to fix the problem on your own, ensure that the rusting on the steel is taken care of. Simply removing the damaged concrete and applying a new concrete mix over the steel isn't enough. The reinforcing steel will continue to rust and cause the problem to recur. Instead, use a wire brush to remove the rust once you expose the reinforcing bars. Any bars that have lost a significant portion of their diameter to rust should be removed entirely and new ones welded into place. After this apply a zinc-rich preparation or anti-rust paint before covering up the reinforcing to protect against corrosion.
Use good waterproofing techniques.
Water penetration into concrete is usually the main cause of concrete cancer. It is therefore prudent to waterproof effectively so as to prevent future appearances of the same problem. Use high-grade waterproofing membranes once you expose the reinforcing bars in the concrete before covering them up. This will slow down the progress of water into the concrete. Alternatively, consider crystalline waterproofing that will seal up the pores in your concrete and transform it into a waterproof barrier.