Cracking, since it is such a major form of pavement deterioration, is usually the deciding factor in determining the proper time for rehabilitation and the appropriate method to be applied. When cracks develop on the surface of the pavement, it is a sign of reduction in pavement integrity and serviceability. Regular repair of pavement cracks is one of the main methods of preventive maintenance, since failure to repair cracks in a timely fashion can lead to accelerated deterioration of the pavement in the form of crack growth, spills, secondary cracks, and potholes. The main causes of pavement cracks are thermal movements and fatigue due to excessive loading. Cracking is an inevitable problem given the network of more than two million miles of asphalt surfaced roads in the United States. It is important to find effective solutions to minimize its effect and to extend the service life of our roads.
​
​
Crack repair consists of crack sealing and crack filling. Usually, crack sealing refers to routing cracks and placing material on the routed channel. Crack filling, on the other hand, refers to the placement of material in/on an uncut crack. For the purposes of this manual, crack sealing will refer to both crack filling and sealing. Specifically, what is usually referred to as crack sealing will be referred to as crack sealing with routing.