Understanding Corrosion of the Reinforcing Steel in Concrete Structures

Steel is an important material when it comes to concrete construction. You need to make sure that the building can hold up to the weight of the bricks, stones, roof and other parts. One problem encountered when using steel to reinforce your concrete structure is corrosion. This is the electrochemical and chemical reaction between the steel and its immediate environment, which leads to deterioration and loss of strength over time. If something isn't done in good time, there is a high risk of the building collapsing because of inadequate structural strength. Here are some of the important things you need to know about corrosion and the reinforcing steel in your concrete structures:

What Causes Corrosion of the Reinforcing Steel?

Naturally, steel is a non-corroding and passive metal. However, certain conditions can trigger chemical reactions that eventually lead to corrosion. Notably, the steel used within concrete is under immense pressure and exposure to chemicals and salts contained in cement and other materials used in construction. When the salts (chlorides) find their way to the steel, they disrupt the dormant layer that protects the steel, making it pit and rust.

Carbonation is also another cause for corrosion on steel. In this process, the cement breaks down into its constituent chemicals changing the alkaline environment in the structure to a neutral one. When carbonation finds its way to the steel reinforcement, rapid corrosion begins because the environment is no longer suitable for its passive coating.

Why is Corroded Steel a Big Concern?

Temperature changes, the wind, pedestrian traffic and building material loads subject concrete structures to immense stress every day. The structure relies on the reinforcing steel to provide the much needed tensile strength to stand up to all the stress. Corrosion weakens the steel and destroys the bond it has with the concrete. Moreover, corroded steel is also a cause of concrete cancer (spalling), which necessitates costlier and more extensive repairs. 

What Can You Do to Prevent Corrosion?

Most of the corrosive chemical reactions rely on the presence of water and air for them to take place or speed up. Therefore, waterproofing alternatives that will seal your concrete structure against infiltrating water will go a long way in limiting chemical reactions such as carbonation. A good example is to use waterproof cement during construction. To add on that, you should be on the lookout for any cracks on the concrete surface and have them repaired immediately. Otherwise, the cracks will for inlets for water and air, creating a conducive environment for the corrosive chemical reactions.

For more information about keeping a building sturdy and secure, contact a concrete repair company.