It’s concrete. Won’t it crack?
Absolutely, but with rare exceptions, only where we “tell” it to. Simply put, concrete is a mixture of sand, cement and aggregate that is made workable by the addition of water. As the concrete cures and this water hydrates from the concrete, it tends to build up considerable stress. This stress is relieved by cracking. We tell it where to crack by providing relatively discreet joints that are saw-cut to specified depths and other tolerances for joint placement as established by the American Concrete Institute (ACI). These joints create a weak plane in the concrete slab that readily relieve these natural stresses. The actual crack is located at the bottom of the joint and is not visible.
