Concrete Control Joints: As the concrete dries, the water in the concrete evaporates. As the water evaporates, the concrete shrinks in volume. The concrete will develop shrinkage cracks as it dries. Shrinkage cracks are a normal part of concrete. We introduce control joints into the wet concrete. The control joints perforate the concrete to allow the shrinkage cracks to form in the control joints. Typically, each of these control joints will have a hairline crack in it.
