摘要: |
Holding strategies for low priority pavements under an asset management program When asset management is applied to the Iowa DOT pavement network, the agency will tum away from a "worst first" approach in order to make investments in pavements that are in better condition where preventative maintenance can better extend the life of a pavement. The result will be improved average pavement conditions at the network level for less investment, an advantage that makes the asset management approach attractive. However, the Iowa DOT will now have the challenge of developing a holding strategy to maintain the worst roads (that used to be first) in an acceptable condition until funding is available to rehabilitate or rebuild the road. Many of these roads have relatively low traffic volumes and asphalt pavements that have delaminating or severely raveling surfaces, deteriorated edges, ruts greater than one inch deep, severe longitudinal cracks, and rolled down thermal cracks with parallel secondary cracks and spalls. Although delaying and limiting major investments on such roads is important to the success of an asset management program, the challenges of dealing with the resulting deteriorated roads are focused on the citizens who use the roads regularly and the employees who must maintain them. It is necessary to identify holding strategies that can be used to keep these roads in an acceptable and safe condition for a modest investment. Success in this area is critical to the success of an asset management program, because stakeholder dissatisfaction with roads in poor condition that are not selected for preservation, rehabilitation or rebuilding can be a major impediment to the successful startup of an asset management program. Considerable research has been published on how to manage pavements using pavement preservation. Such published research includes monitoring pavement condition; optimally budgeting, prioritizing, selecting treatment types; and designing and constructing treatments. However, little research has been published about how to economically and safely continue to use roads that have too much deterioration for preventative maintenance, and cannot be rehabilitated or rebuilt due to a shortage of funds. Guidance is needed regarding holding strategy selection that can be used by district maintenance personnel and staff engineers. Possible strategies might include: (1) mill and fill; (2) repeated applications of thin surface treatments (say on a one, two, or three year cycle); (3) strip applications of the above; (4) thin overlays; (5) cold or hot in-place recycling, possibly with a thin surface treatment as the final surface; (6) expanded use of pothole patchers; and (7) a combination of the above strategies. In addition, a systematic method has not been devised for deciding what actions should be taken by in house forces and what actions should be contracted out. It would be desirable to develop such a method as part of this research. Under this proposed investigation, research assistance will be provided for a pilot project to use holding strategies to extend the life of a relatively low volume state route with the goal of providing a safe and adequate solution that will not divert investments to preservation projects. Assistance will be provided regarding materials selection, design guidance and comparison observations. Since similar projects may follow in other locations in the state using other methods, care will be taken to fully document the research methodology so it could be repeated in the future. The objective of the proposed research project is to assist Iowa DOT in developing strategies for maintaining lower volume highways that are near the end of their service life to a satisfactory level in order to delay the larger expense of rebuilding them. |