A primary problem associated with recycling is the pollution created by the combustion of asphaltic material during heating in a conventional drum dryer. Also of importance is the aging characteristics of recycled materials and their performance. This report covers the testing and design methods, construction procedures, resulting air pollution, economy of operation, and performance of a pavement recycled and utilized as a surface course in southeastern Wyoming.

This project demonstrated that highway pavement recycling with a heater-scarifier-repaver, adding additional asphaltic material and new asphaltic concrete pavement to the mixture, can satisfactorily restore these surfaces. The proper design of new asphaltic concrete pavement material to be added was considered. The laboratory investigative work and necessary construction controls are discussed. Careful records of fuel consumption by the heater-scarifier-repaver machine were kept as were all costs attributed to the project for comparison with conventional resurfacing methods. This method of surface restoration compares very favorably economically with conventional methods.

This synthesis report will be of special interest to pavement designers, materials engineers, and others seeking information on portland cement concrete resurfacings (overlays) placed over both portland and asphalt cement concrete pavements. Information is presented on the various practices in use for the design, material selection, and construction techniques associated with each pavement type. Additional information is provided on resurfacing experience and performance, including an Appendix cataloging more than 700 existing resurfacing projects in North America. Transportation agencies in the United States are continuing to develop pavement management systems which take an objective and structured approach to life-cycle cost analysis requirements for pavement rehabilitation project analysis. This report of the Transportation Research Board also discusses the considerations involved in the selection of technically feasible resurfacing alternatives. Based on the longitudinal experience of 375 resurfacing projects that were cataloged in 1982 and the more than 700 projects identified in 1993, much useful information on the performance characteristics of portland cement concrete resurfacing is presented.