The project produced a mechanistic-empirical (M-E) pavement design guide that includes (a) a Guide for M-E design and analysis, (2) companion software with documentation and a user manual, and (3) implementation and training materials. The guide includes procedures for the analysis and design of new, rehabilitated flexible, rigid, and semi-rigid pavements. It uses M-E numerical models to analyze input data for traffic, climate, materials, and structure to estimate damage accumulation and predict performance, in terms of distress and smoothness, over service life for comparison with threshold values (i.e., it does not provide structural thickness as an output).

AASHTO's Guide for the Design of Pavement Structures is the primary document used to design new and rehabilitated highway pavements. It was based on empirical design approaches derived from the AASHO Road Test that included limited structural sections at one location, and with limited traffic levels compared with those of the present day. Because mechanistic approaches more realistically characterize in-service pavements and improve the reliability of designs, design approaches that are based on mechanistic principles would be desired. However, because of gaps that exist in the knowledge base, mechanistic design methods need to be supported by empirical relationships, and many of the issues relating to the M-E approach need to be better defined before practical and realistic design procedures can be developed and put into use. Thus, there was a need to address related issues and develop a Guide for Design of New and Rehabilitated Pavement Structures, based on M-E principles, accompanied by the necessary computational software, for adoption and distribution by AASHTO.

The research reviewed relevant domestic and foreign literature, research findings, current practices, and databases relative to pavement analysis and design; developed a design guide based on sound mechanistic principles; presented the Guide as a computational software; and provided related documentation and training materials. The Guide provides a uniform basis for the design of flexible, rigid, and composite pavements and employs common design parameters for traffic, subgrade, and environment. It uses M-E performance models that were calibrated using field data from the Long Term Pavement Performance studies and other sources. The final deliverables produced by this project are available here as a ZIP file (63.5 MB).

The research performed in this project provided the basis for AASHTO Mechanistic-Empirical Pavement Design Guide and the AASHTOWare Pavement M-E Design software--available from the American Association of State Highway and Transportation Officials (AASHTO), 555 12^th Street NW, Suite 1000, Washington, DC 20004; info@aashto.org.