Seal Coats as a Preventive Maintenance Technique
Posted by Jesse Willoughby on Thu, Apr 09, 2009 @ 05:31 AM
General
Many companies have had a formal preventive maintenance program for years. Some folks, however, are behind in adopting a regular seal coat application schedule for every few years. Seal coats are used extensively as a preventive maintenance technique for asphalt pavements throughout the San Francisco Bay Area. While routine maintenance can be characterized as a reactive process in which immediate repairs are made to existing distress, preventive maintenance treatments help to preserve a pavement and extend its useful performance life. This concept is illustrated in Figure 2-1. It is desirable in California to place seal coats on a 2 to 5 year cycle, but this is not always possible due to funding constraints. In rough economic times, it is a great alternative to complete repair.
The process for selecting pavements to receive seal coats will vary among the locations and many circumstances. In
general, the process starts with maintenance grounds supervisors because they are most familiar with the roads in the section and inspect them often. They are also aware of the resurfacing and maintenance history of a particular pavement area. The maintenance grounds supervisor generally prepares a list of candidate projects, and the list is reviewed and modified as appropriate by the facility manager or property manager before being submitted for approval.
Seal coats provide no additional structure to an existing pavement, so pavements that are structurally deficient are not candidates for seal coats. In addition, because wide cracks or cracks experiencing large movements are expected to reflect through the seal coat, pavements with extensive amounts of distress are generally not good candidates for a preventive maintenance treatment. There is, however, still a considerable amount of seal coat applied as a Band Aid to hold the pavement for a few years until reconstruction or rehabilitation can be funded.
In many cases, spot base repair, edge repair, crack sealing, strip/spot seal coat, or level-up work may be required to make an existing pavement ready to receive a seal coat and to maximize the life of the pavement.
Factors that can affect the decision to use a seal coat as a maintenance treatment include the following:
♦ condition of the existing pavement
♦ effectiveness of a seal coat in addressing the existing pavement deficiencies
♦ cost of the seal coat compared to other treatments
♦ traffic volume
♦ percent truck traffic
♦ repairs needed prior to the seal coat.