R Gary Hicks

SELECTING A PREVENTIVE MAINTENANCE TREATMENT FOR FLEXIBLE PAVEMENTS

Maintenance engineers have been applying treatments to both flexible and rigid pavements ever since there have been these types of pavements. The types and application of various treatments for both corrective and preventive maintenance have been the subject of research studies over a number of years, and many publications have reported these findings. FHWA recently initiated an effort to encourage departments of transportation at all levels to begin, or extend, the practice of preventive maintenance, since there simply is not enough money available to continue the types of maintenance currently employed. Flexible pavement preventive maintenance is specifically addressed, including the types of pavements that are candidates for preventive maintenance, the available treatments, where and when they should be used, their cost-effectiveness, factors to be considered in selecting the appropriate treatment strategy, and a methodology to determine the most effective treatment for a particular distress.

Guide for Investigating and Remediating Distress in Flexible Pavements: California Department of Transportation's New Procedure

In 2001, the California Department of Transportation (Caltrans) initiated a 3-year,

Development of Enhanced Alaska Pavement Preservation Program and Strategy Selection Guide

7 million project with MACTEC, Inc. The project included on-call flexible pavement consulting services to Caltrans in the areas of new products, asphalt rubber, modified binders, moisture sensitivity, failure investigations, independent quality assurance, training, laboratory testing, pavement maintenance, pavement rehabilitation, and asphalt recycling. One of the key tasks of the project was to develop a comprehensive guide and a detailed procedure to investigate flexible pavement distresses and develop cost-effective remedies and repair strategies. The emphasis of the procedure is on addressing premature distress and certain problems that might arise during pavement construction. The guide contains two manuals: (a) an office manual that describes the types of flexible pavement distress, identifies the factors that affect distress and performance, and provides tools that can be used to characterize distress condition, determine likely causes, and generate a corrective solution and (b) a field manual for use in the field by experienced engineers familiar with the new tools and requiring little instruction on its application. The principles presented in the guide are based on modern pavement engineering technology and are applicable to the practices of many federal, state, and local agencies. The process presented in the guide is summarized, and several of the new tools that have applicability to other agencies are described.

EFFECTS OF TEST PARAMETERS ON RESILIENT MODULUS OF LABORATORY-COMPACTED ASPHALT CONCRETE SPECIMENS

The Alaska Department of Transportation and Public Facilities (DOT&PF) wished to enhance its existing pavement preservation management program by using effective pavement preservation treatments for cold regions. This initiative would extend pavement life and defer the need for more costly rehabilitation. By collaborating with the California Pavement Preservation Center and the Alaska University Transportation Center, the Alaska DOT&PF recently completed a pavement preservation research project to improve its pavement preservation program for flexible pavements. Research tasks included conducting an international survey of pavement preservation in cold regions, reviewing literature on cold region pavement preservation treatments, monitoring existing preservation treatments that Alaska used, developing a pavement preservation database, and creating an online computer program for treatment selection. The database for pavement preservation treatment tracking is a web-based online program that includes standard types of pavement preservation strategies used in Alaska; pavement construction, traffic, weather, and other performance-related information; an integrated Google Map function to show the location of pavement preservation projects; and multiple pavement condition survey results with supporting documents. The strategy selection program is integrated within the pavement preservation database. The program sees results of the survey and other information on Alaska treatments to conduct treatment strategy selection and life-cycle cost analysis. Workshops have been given on preservation treatments used in cold regions and use of the database and strategy selection process. Tools developed for the Alaska DOT&PF should be helpful for long-term implementation of an effective pavement preservation program. Other agencies could learn from Alaskas experience.