There are a few reasons why concrete cracks, but the most common reason by far is shrinkage cracking. When your concrete patio or driveway is poured, it is in liquid form, which it has to be so it can be properly formed. As the concrete begins to dry, the water within evaporates, and as it does, the concrete will begging to shrink. A concrete slab will shrink about ¼ inch for every 100 square feet of surface space. When concrete dries and shrinks, cracking can occur hours after being poured. Any crack that is ⅛ of an inch or smaller on your patio or driveway is considered standard. Some hairline cracks may form and disappear after a month or two.
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