Concrete Spalling: Definition, Causes, Repair, and Prevention

​Concrete’s strength, aesthetics, and durability make it an ideal material for a variety of use cases, from driveways to patios and more. So why does perfectly smooth concrete peel, pit, and flake? Hint: it’s not always due to age. These could be signs of concrete spalling.

What is Concrete Spalling?
Concrete spalling occurs when moisture enters the concrete, causing the surface to peel, pit, or flake and expose the aggregate underneath. Spalling can also be caused by salt, which is common in colder regions like Dayton. The moisture (and salt) push outward from inside the concrete, which causes visible damage.

​Concrete Spalling Causes
Moisture and salt are the primary culprits behind concrete spalling. Salt that’s used on icy roads can oxidize or rust the reinforcing steel. However, the main cause is likely due to the way the concrete sets. Alkalis in the concrete mixture and carbon dioxide in the air can interact and may force cracking that allows moisture to seep in.
 
Once moisture enters cracks in the concrete, the cold weather freezes it and makes it expand. This puts extra pressure on the concrete, which can lead to further cracking. Eventually, all this stress can cause concrete spalling.

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​How to Repair Spalled Concrete
Concrete spalling is a common issue, one that’s easy to tackle if you catch it early. For minor spalling damage, in most cases you can simply apply a new surface layer to restore its smooth appearance. This new layer will fill in any existing cracks, pits, or holes. 

​To do this, you’ll need the right materials:
 

• Concrete resurfacing product
• Pressure washer (if you don’t own a pressure washer, you can usually rent one)
• Long-handled squeegee
• Paddle-like drill attachment for mixing
• Container for mixing your concrete, such as a bucket or wheelbarrow

 
It’s best practice to have all your materials in place prior to beginning. It saves time and prevents you from running to the hardware store once you’ve mixed your concrete.
 
First, pressure wash your surface to remove any debris that may be stuck in the cracks and to remove any debris on the surface that might affect the smoothness of your new application.
 
Mix your resurfacer according to the directions, ensuring a lump-free mixture with the paddle drill attachment. Apply a pre-fill to any cracks or holes in your driveway, then apply an even layer of resurfacer to the entire area. Use your long-handled squeegee in a push-and-pull motion to spread the resurfacer and create an even layer.

​Preventing Concrete Spalling
Preventing concrete spalling usually happens when the concrete is first poured, such as ensuring just the right balance of water and concrete mix. If that ship has sailed, then focus on proper maintenance. Keeping a watchful eye on your concrete and repairing it early when issues appear will be key in maintaining its appearance.
 
For help repairing and restoring your concrete, contact us today

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