Preventing Concrete Spalling
How to: Preventing Concrete Spalling From Ever Happening in Basements and Other Concrete Surfaces
Concrete spalling is concrete that has been damaged, chipping off, broken, or flaked. This happens due to reasons such as excess moisture, temperature, weather, corrosion, poor installation making the concrete wear down, or mechanical pressure that stresses the concrete. Some refer to concrete spalling as concrete cancer. It can cause serious hazards and loss of property. Therefore, it is an issue that needs immediate attention, but how can one prevent it from happening in the first place?
Causes of Concrete Spalling
Concrete spalling prevention will be a lot less costly than having to repair the damage. Understanding how it happens in the first place will help explain how to prevent it from happening in the future. One of the main reasons spalling happens is a natural process known as carbonation. Water gets into the concrete and causes the rebar and other materials embedded in the concrete to corrode. This creates bulges and cracks in the concrete surface.
Another reason spalling happens is due to water. Rainwater or water from another source will make its way into the small openings of the concrete. On cold days this will freeze, and causes the concrete to break due to expansion. As this continues to happen, cracks develop on the surface.
In addition, rock salt and de-icing salts are not good for concrete driveways as they cause spalling just like rainwater causes spalling. The water melts prematurely while the outside temperature is still cold enough to freeze it, and once it seeps down into the cracks of the concrete, the water refreezes and causes cracks.
High temperatures are another reason for concrete spalling. When concrete is exposed to high temperatures over time or all of a sudden, the surface is much hotter than the concrete beneath, which will lead to thermal expansion that causes stress between the two surfaces.
Preventing Concrete Spalling
There are a few different ways to prevent concrete spalling or cancer. One of the ways is to protect the steel reinforcement bar from corrosion by providing the right amount of concrete cover, to begin with. One inch of cover is needed for rebar, it should not be positioned at a distance lesser than an inch from the concrete surface. In addition, concrete needs to be appropriately amalgamated while it is being installed.
Air entrainment is another method of preventing concrete spalling. It is the introduction of small bubbles in the concrete by adding an air entraining agent, such as Portland cement or a surfactant while mixing the concrete.
Once the concrete has been poured and cured properly, the carbonation process can be slowed down by painting the concrete regularly. In addition, use a sealer that repels water after the concrete has cured. This is the most important step to preventing spalling in concrete as it prevents moisture from penetrating the concrete. If the concrete is indoors, then make sure the area is well-ventilated to prevent humidity from building up.
