Results of Bad Concrete Poured on a Driveway

Spalling

• Spalling is a concrete condition where the surface breaks off in small or large areas to a depth of about 5 mm, which usually happens during the first year after the driveway was poured and the cause is not always within the control of the homeowner. The problem lies in the presence of calcium chloride and sodium chloride, found in most deicing salts used by local road crews during winter. Even if you don't use the salt yourself, your car drives over it and tracks it back to your driveway.

Cracking

• Since concrete is susceptible to tension and shear stresses of varying types, cracks in concrete are probably the most common problem found. Sometimes they are only little cracks, which don't bother you too much, and sometimes they more closely resemble chasms, which ruin the aesthetics of the driveway and make it rough on vehicular and foot traffic. Two common causes for cracking are too much water in the mix or too rapid drying.

Blisters

• Blisters are small, hollow bumps that form on the concrete's surface, ranging from the size of a dime to several inches across. The usual cause of concrete blisters is troweling too soon while the pour is still settling. The blisters themselves are simply air pockets trapped directly beneath the surface. Choosing exactly when to trowel is a delicate part of the finishing process. Wait too long and the mixture is too dense; do it too soon and you end up with a moon surface instead of a smooth driveway.

Popouts

• Conical-shaped fragments that break free from the body of the driveway are referred to as "popouts." Though annoying and a threat to the overall cosmetic appeal of the driving surface, popouts are a localized problem and should not pose a threat to the overall integrity of the driveway. The usual cause of a popout is when a particular type of aggregate used in the mix -- often soft shale or limestone -- absorbs moisture and expands enough to break free.