Increasing budget constraints require that states and local agencies perform more work with less money. Historically, the emphasis of local highway departments has been on building new roads, but the new focus is on maintaining and preserving existing pavement surfaces. This shift has resulted in three types of pavement maintenance operations:
Preventative Maintenance
A preventive maintenance program is a systematic approach to using a series of preventive maintenance treatments over time. A single treatment will improve the quality of the pavement surface and extend the pavement life, but the true benefits of pavement maintenance are realized when there is a consistent schedule for performing the preventive maintenance.
An effective pavement preservation program integrates many preventive maintenance strategies and rehabilitation treatments. The goal of such a program is to extend pavement life and enhance system-wide performance in a cost-effective and efficient way. Studies show that preventive maintenance is six to ten times more cost-effective than a “do nothing” maintenance strategy.
Benefits of pavement preservation include improved customer service and substantial life cycle cost savings; treatments are especially cost-effective when applied early in the life of a pavement. In addition, by extending the life of a pavement section until it can be rehabilitated, preventive maintenance allows an agency to even out its maintenance budget from year to year, which otherwise can vary greatly.
Preventive maintenance activities can include conventional treatments such as crack sealing, chip sealing, fog sealing, rut filling, and thin overlays. They can also include emerging technologies; such as ultra-thin wearing courses, very thin overlays, and microsurfacing applications. Aside from crack treatments, all of these treatments leave the pavement with a new wearing surface.
Preventive maintenance is generally planned and cyclical in nature. Its intent is to repair early pavement deterioration, delay pavement failures, and reduce the need for corrective maintenance and service activities. Although this type of maintenance is not performed to improve the load-carrying capacity of a pavement, it extends the pavement's useful life and level of service.
Corrective Maintenance
Corrective maintenance is performed to improve or extend the functional life of a pavement. It is a strategy of surface treatments and operations intended to slow progressive failures, and reduce the need for routine maintenance and service activities.
Corrective maintenance differs from preventive maintenance primarily in cost and timing. While preventive maintenance is performed when the pavement is still in good condition, corrective maintenance is performed when the pavement is in need of repair, and is therefore more costly.
Delaying maintenance allows increased occurrence of pavement defects and increased severity, resulting in more extensive and expensive work. Consequently, the life cycle costs of the pavement will be considerably increased when corrective maintenance is performed.
Corrective maintenance is much more reactive than preventive maintenance, and is performed to correct a specific pavement or area of distress. Activities include structural overlays, mill and overlays, pothole repair, patching, and crack repair.
Emergency Maintenance
This maintenance activity may be performed during an emergency situation, such as when a blowout or severe pothole must be repaired immediately, generally for safety reasons or to allow for traffic to use the roadway. Emergency maintenance also describes those treatments that hold the surface together until a more extensive rehabilitation or reconstruction treatment can be accomplished.
When emergency maintenance is needed, some of the typical considerations for choosing a treatment method are no longer important. Cost may be the least important consideration after safety and time of application are considered. Materials that may not be acceptable when used in preventive or corrective maintenance activities, for cost or long-term performance reasons, may be highly acceptable when used in an emergency situation.