Preventive Maintenance Treatments Showcase
AASHTO Subcommittee on Maintenance
Interest in the concept of pavement preservation and the use of preventive maintenance techniques has continued to grow across the country as state and local governments learn of the success stories of states such as Michigan, California, and Georgia that have implemented pavement preservation programs.
Workshops and Forums sponsored by FHWA, AASHTO and the Foundation for Pavement Preservation (FP2) along with training courses developed by the National Highway Institute have peeked the interest of maintenance engineers and researchers alike in the use of preventive maintenance treatments to extend pavement life.
Surveys conducted over the last couple of years indicate that most State Highway Agencies generally utilize conventional treatments such as thin HMA overlays and surface seals as a part of their maintenance operations. However, very few states make use of the wide variety of preventive maintenance "tools" that could be available to them to more cost effectively preserve their pavements. This is generally due to a lack of awareness or a reluctance to use treatments or products with which the agency has not had any experience.
In an effort to raise the awareness level of State Maintenance Engineers about preventive maintenance treatments, the AASHTO Subcommittee on Maintenance (SOM), Pavements Task Force, working with FHWA, Alabama DOT, and industry through FP2 agreed to sponsor a "Showcase of Treatments" during the 2002 SOM meeting in Gulf Shores, Alabama. This cooperative effort began in the fall of 2001 with a planning meeting in Auburn, Alabama at the NCAT test track facility. It was the consensus of this group that it would be desirable to demonstrate as many treatments as possible, but the final selection should be based on the level of interest of the State Maintenance Engineers. This "Showcase" could give the SOM conference attendees an opportunity to compare various treatments and discuss design and placement techniques with industry representatives.
A survey of the SOM membership was conducted to determine the types of treatments they would like to see applied. (A summary of the responses to this survey can be provided.)
Upon completion of the survey, an effort began to contact industry associations to sponsor the project, and identify contractors willing to place the desired treatments. Jim Moulthrop, representing industry, coordinated this effort through FP2. John Lorentson and his Alabama DOT staff, identified the project location, provided data on the existing pavement structure, and agreed to furnish traffic control and pavement markings as well. The "Showcase" project is located on Alabama State Route 135 which runs through Gulf State Park near the conference hotel. The existing pavement is in good condition, and consists of 5" HMA on 6" Sand Clay base. Alabama DOT agreed to document the treatments through slides or videos as they are placed, and will make a presentation during the conference. They will also perform long term monitoring and evaluation of the treatments, complementing similar research being done by the Arizona DOT. An afternoon field trip to the project site has been included as part of the conference agenda.
The treatments scheduled to be placed for the showcase include: Conventional Chip Seal, Polymer Modified Chip Seal, Ultra thin 4.75mm superpave HMA overlay, Koch Road Armor macro seal, Ergon DRM process, and an Ultra thin wearing surface by produced by Koch known as Nova Chip. Crafco Industries will be providing a crack sealing demonstration during the field trip. The other treatments will be placed prior to the conference. Efforts were continuing at the time of this writing to find a contractor to place slurry seal and microsurfacing. These treatments are not routinely utilized in Alabama, so there were no contractors readily available. Nearby states do have some slurry seal work being performed, so there is still a possibility that slurry can be included in the showcase. The recycling industry (Cold in Place/Hot in Place) supported the concept of a showcase, but due to the high cost of mobilization ,and the existing work load of available contractors, determined that it was not feasible to participate.
Steve Varnedoe, NCDOT
SOM- Pavements Task Force Leader
John Lorentson, Al. DOT
Jim Moulthrop, KOCH