HOW TO REPAIR SPALLING CONCRETE

Concrete that is spalling can be a frequent issue where a portion of the surface peels off, breaks , or is chipped away. Also called scaling, it’s caused by a surface that is weak and vulnerable to being damaged.

Spalled concrete can be the result of any one or all of these:

  • Freeze-thaw cycles
  • De-icing salts
  • Poor finishing techniques
  • Improper curing
  • A bad concrete mix

When your concrete starts sputtering there are a few solutions to repair it:

  • Repair the spalled areas with an appropriate color-matching compound
  • Have your concrete resurfaced using an overlay
  • Replace the entire slab

HOW TO PREVENT CONCRETE SPALLING

Sealing is the most effective method to stop spalling due to moisture. When you are putting in new concrete use an impermeable waterproofing sealer 28 days after the placement of concrete and then every few years after that.

A properly mixed concrete mix can also aid in preventing spalling. Air entrainment can be particularly efficient in resisting freeze-thaw cycles. If the concrete’s moisture is frozen, the air cells reduce internal pressure by creating microscopic chambers that allow expanding water when it cools.

FIXING A SPALLED DRIVEWAY

Spalling that is caused by freezing and melting and deicing chemicals can leave ugly pits in concrete driveway.

Question:

What’s the reason for this failure of the surface on my concrete driveway? What can I do to fix it? The driveway is about 6 years old, and it is about 1,000 square feet However, only the few hundred square feet on the side of the doors are showing indications of damage.

Answer:

This type of surface defect also referred to as scaling or spalling, is more frequent in colder climates, where freeze-thaw cycles as well as deicing chemicals are common. The freezing causes the water in the capillaries in the concrete to expand causing pressure. In time, the expanding pressure created by the repeatedly freezing or thawing could tear away the top surface of concrete. This can leave pits and expose fine aggregate. Deicing chemicals can exacerbate the already stressed concrete by allowing even more water to enter the concrete, increasing the extent and size of spalling failures once the freeze takes place.

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