The Right Treatment, in the Right Place, at the Right Time
According to the Foundation for Pavement Preservation, pavement maintenance involves doing the right treatment, in the right place, at the right time. To achieve this, good management and an understanding of the choices are required.
For a given set of conditions, at a given time, there is usually one best repair. If a road needs an overlay, a chip seal will not suffice. If crack repairs will do the job, there is no good reason to place a more costly slurry seal. Sometimes the wrong choices are made due to politics, citizen complaints, or lack of money. If wrong choices are made, it is important to understand why they were made and what the consequences are.
There are four different categories of maintenance activities: demand, routine, corrective and reconstructive.
The table below explains how these different activities fit into a pavement management plan. Some can be performed before significant deterioration occurs. An example is a chip seal done before cracks develop. Preventive maintenance must be done before even moderate cracking occurs, or it will not last as long as it should.
|Type of maintenance||Planned?||Performed before deterioration?||Extends pavement life?|
Performing a technique to correct a hazard or meet a service request. Pothole patching in the spring is the most common form of demand maintenance.
Performed on a routine basis for operational reasons. Examples include mowing grass, cutting shoulders, and striping centerlines.
Application of a treatment before significant deterioration occurs. It typically extends the life of the pavement and is usually planned. Surface treatments are usually considered preventive maintenance.
Fixes pavement failures after they have occurred. A semi-permanent area patch is a form of corrective maintenance. A truing and leveling layer to fill minor ruts, with a follow up overlay, is another example. Corrective maintenance generally costs more than preventive or routine maintenance.
Planned maintenance is generally preferred to unplanned (demand) maintenance, and preventive maintenance is preferred to corrective maintenance. The figure below shows the relationship between pavement condition and the life of the pavement. The pavement condition starts in very good shape and deteriorates slowly at first. Maintenance repairs done early in the life of the pavement are much less expensive than those done later.
There is also a definite relationship between pavement condition and the various levels of maintenance. Routine and preventive maintenance are the most economical options. Reconstruction techniques are the most expensive. They are usually done when there is no other choice. There are times in the life of a pavement when the best alternative is to do nothing. This is usually when the pavement is not a candidate for maintenance, and rehabilitation or reconstruction are not yet justifiable.
Selecting the repair
The first step is to evaluate the road. Divide the road network into segments, and do a condition survey on each segment. A condition survey documents the extent and severity of each type of pavement distress. Using the results of the condition survey, determine the possible pavement repairs. During the evaluation, ask the following questions:
- What kind of maintenance can fix the defects found?
- What repair, if any, will extend the life of the pavement
- Which maintenance technique will be the most cost effective?
The primary Repair Treatment Categories are as follows, listed with their average lifespan/duration: Crack treatments, 3-5 years; Patching 1-10 years; Thin wearing courses, 3-10 years; Overlays, 5-15 years; Recycling, 10-20 years; Reclamation, 15-50 years; and Reconstruction, 25- 50 years.
Within a given treatment category, specific operations may not fix the distress in question. One example is a fog seal, which will not restore skid resistance, due to low friction. In actual field evaluation, other factors will need to be taken into account.