Routing and sealing is a common crack-repair method in which the crack is made wider at the surface with a saw or grinder, and the resulting groove is filled with a flexible sealant. This prevents water and debris from entering the crack yet allows the crack to open and close in response to loads or changing temperatures.
Although it's not a complicated technique, workers must perform several crucial steps to ensure a durable repair. This article gives a step-by-step explanation of the proper procedures for crack routing and sealing. Though it focuses specifically on repairing a crack in a parking deck, much of the advice applies to cracks in other structures as well.