Is pitting in concrete normal?
Scattered, shallow surface pits are common and usually cosmetic rather than a structural problem. The concrete below the surface is sound; what has broken down is the thin top layer of paste. Pitting becomes worth a closer look only when it is deep, spreading, or paired with a surface that crumbles, which points to a weak or contaminated surface skin rather than ordinary pitting.
Why did my new concrete driveway pit?
New-slab pitting is almost always a finishing, mix or exposure issue. The most common cause is troweling the surface while bleed water is still rising, which works water back into the top skin and leaves it weak and porous. An over-wet mix, early de-icing salt before the concrete has matured, and freeze-thaw all add to it. In US and Canadian climates, salting a first-winter driveway is a frequent trigger.
Does the form panel cause pitting on a formed wall?
Rarely. Pitting on a cast vertical face is mostly trapped air and bleed water pinned against the form, driven by the mix, the vibration, the pour rate and the release agent. A smooth, sealed phenolic or HDO form face helps surface air escape and gives a denser cast surface, so the right face is part of the prevention rather than the cause. Over-applied release agent, by contrast, is a named contributor to surface voids.
How do you fix pitted concrete?
For cosmetic pitting, clean the area of dust and any salt contamination, dampen it, then work a cementitious patching compound or thin resurfacer into the pits and finish flush to match the surrounding texture. A broadly pitted slab is better served by a bonded overlay across the whole area than by spot-filling many small craters. Seal the repaired surface and keep de-icing salt off exterior flatwork through the next winter.
Will sealing prevent concrete pitting?
Sealing helps by slowing the water and chloride penetration that breaks down a surface skin, but it is not a cure on its own. The bigger levers are a sound mix, finishing only after bleed water has stopped rising, air entrainment for freeze-thaw exposure, and proper curing. A well-cured, sealed surface resists the salt and frost that drive most pitting.
