Summary of International Scanning Tour for Pavement Preservation
National Program Director for Public Works
HDR Engineering, Inc.
Chair, International Affairs Committee
Federal Highway Administration International Technology Scanning Program
The International Technology Scanning Program accesses and evaluates foreign technologies and innovations that could significantly benefit U.S. highway transportation systems. Access to foreign innovations is strengthened by U.S. participation in the technical committees of international highway organizations and through bilateral technical exchange agreements with selected nations.
Traditionally, highway agencies have allowed the ride quality and structural condition of their pavements to deteriorate to fair or poor condition before taking steps to rehabilitate the pavements. The aim of rehabilitation is to repair structural damage and restore measurable pavement conditions such as ride, rutting and cracking. This is a costly and time-consuming activity with associated traffic disruptions and inconvenience to adjacent businesses and residences. In recent years, an increasing number of highway agencies have found that applying a series of low-cost pavement preservation treatments can extend the service lives of their pavements. This translates into a better investment and increased customer satisfaction and support.
France, South Africa and Australia were identified as nations that have innovative programs as well as new treatments for pavement preservation.
Objectives and Panel Composition
The objective of this scanning tour was to review and document innovative techniques, materials, procedures and equipment utilized in the host countries relative to pavement preservation and to evaluate these elements for potential application in the United States. To this end, the panel had meetings with government agencies and private sector organizations involved with pavement preservation, and also participated in site visits to observe the results of pavement preservation techniques and strategies.
The Federal Highway Administration (FHWA), an agency of the U.S. Department of Transportation, and the American Association of State Highway and Transportation Officials (AASHTO), jointly sponsored the Pavement Preservation International Scanning Tour. The delegation included members representing state departments of transportation in Georgia, Michigan, Pennsylvania, and Texas; National Association of County Engineers (NACE); FHWA; National Parks Service; American Public Works Association (APWA); and, from the private sector, Koch Materials Company and Kristen Betty and Associates.
The team members developed a list of amplifying questions, which were sent to each country prior to the tour. These questions gave the host countries a good understanding of the topics of interest to the U.S. team and enabled the hosts to plan their presentations and site visits accordingly. The amplifying questions focused on four major topics:
The team noted several Key Findingsâ€”actions taken that have a marked impact on pavement preservation activities and program success:
All the countries visited have made a commitment to design and build long-lasting structural pavement sections on their national roadway networks. This decision has caused all of these nations to focus maintenance activities on surface courses in order to preserve the large investment in the underlying layers. This, in turn, promotes the use of relatively low-cost seals and thin overlays as the primary maintenance techniques, instead of more costly types of rehabilitation.
By providing initial high structural capacity, emphasis is placed on the structure using relatively low-cost seals and thin overlays on set, repeatable cycles. For the most part, rehabilitation is a minor portion of the agencies' maintenance program. Consequently, pavement preservation techniques are emphasized.
All three countries use only quality materials for both bitumen and aggregate. Generally, crushed granite and proven polymer-modified asphalt binders are used. This is ensured through the use of very rigorous specifications. Materials sources are specified and there is no inhibition to using sources a great distance away from the project site.
Warranties, usually four years in duration, are used in contracts when applying preventive maintenance techniques. The functional properties warranted are friction, rutting, and smoothness. The responsibility of the contractor for the repair of non-compliant sections reduces with time and traffic. A secondary effect of the application of warranties has been the innovation of materials and mixtures by contractors and material suppliers.
A system exists in France named the "Charter of Innovation," by which the government and industry share in the risk of experiments to develop new and innovative products. Requests for Proposals (RFPs) are issued annually for new products and test sections are constructed. Surveys are conducted and the company and the government share in their cost. Successful products are then accepted nationally for inclusion in the preventive maintenance program.
After discussing and evaluating what they had seen, heard, and experienced in the three countries, the team developed the following recommendations that may have a potential for implementation in the United States.
Deep Subbase, Deep Base, and Extended Pavement Design Life
Demonstration projects with deep subbase and deep base designs should be initiated in different regions of the United States to determine the effectiveness of this design strategy.
Agencies should include pre-coating of chips in their chip seal specifications; geotextile-reinforced chip seals should be tested and evaluated in both freeze and no-freeze environments; agencies that do not use modified binders for chip seals should be encouraged to do so; agencies should be encouraged to review their specifications and upgrade them where appropriate so that superior aggregates are used and improved service life is accomplished; agencies should be encouraged to review their design practices for chip seals and consider placing them on base or subbase courses to prevent moisture infiltration.
Timely Preventive Maintenance
Chip seals should be applied earlier in the distress cycle.
The successful practice in New South Wales, Australia, of placing thin (40-60 mm) asphalt overlays on PCC should be investigated.
Innovative Methods, Practices and Procedures
AASHTO and FHWA should develop a mechanism to evaluate and implement new and innovative products and processes.
AASHTO and/or FHWA should conduct a seminar to share best practices and also investigate the possibility of demonstration projects in the United States using long-term maintenance contracts.
Pavement Condition Survey Equipment
An investigation of Road Crack, a pavement condition survey vehicle developed in New South Wales, Australia and similar vehicles should be conducted to fully evaluate the potential for use by transportation agencies. And, if warranted, a pilot program should be developed for a side-by-side field evaluation of these vehicles.
A small group of the scanning team members has developed a technology implementation plan that outlines a series of activities to document, showcase, apply and evaluate the innovative pavement preservation techniques, processes, materials and equipment utilized in the tour hosting nations. These activities will be directed to educate and demonstrate to the United States highway community the effectiveness and value of these innovative technologies.
The full report will be published this spring and will be available on the FHWA website at www.fhwa.dot.gov.
To reach Jerry Fay, call (602) 508-6623 or send e-mail to firstname.lastname@example.org.
Pachuca de Soto, Hidalgo, Mexico to host 2002 Mexican Public Works Conference
The 11th Mexican National Public Works and Services Conference will be held May 29 through 31, 2002 in the beautiful colonial city of Pachuca de Soto, located in the historic Sierra Madre mountains 60 miles from Mexico City.
This annual event organized by the Mexican Municipalities Association (AMMAC), brings together public works officials and vendors from throughout Mexico to discuss technical and managerial issues affecting the delivery of public works and services in Mexico. It is also an opportunity for the APWA/AMMAC task force to review their work program for the upcoming year. APWA President Richard Ridings will lead a delegation of APWA members that will be attending this conference as participants and presenters.
Founded in the sixteenth century, Pachuca evolved as an important colonial silver mining center. Today Pachuca, the State of Hidalgo, is an important government and commercial center with a bustling population of 250,000. Its proximity to Mexico City makes access via Mexico City's many international flights convenient.
The AMMAC Public Works and Services Conference is a unique opportunity to learn about the challenges facing our Mexican counterparts as their country enters a new era of more open, democratic governance. Last year's conference in Ciudad Juarez was attended by more than 25 APWA members.
APWA members interested in attending or participating in the conference can contact Bob Kass at (408) 866-2150 (e-mail: Bobk@ci.campbell.ca.us), or Julio Fuentes, Chair of the APWA/AMMAC Task Force at (619) 533-3092 (e-mail: JCF@sdcity.sannet.gov). Vendors are particularly encouraged to take part in the conference's trade show.
Members can visit AMMAC's website at www.ammac.org.mx for conference information, or www.pachuca.com for more information on Pachuca de Soto.