In 1964, Washington State University constructed a test track for the purpose of testing full scale experimental pavements under actual field conditions encountered in Southeastern Washington. The construction of the track and the first four years of operation were sponsored by the Washington Department of Highways in cooperation with the U.S. Department of Transportation, Federal Highway Administration. The Asphalt Institute contributed both financial and technical aid to the project. Others, such as the Chevron Asphalt Company and the Firestone Tire and Rubber Company, have contributed both materials and technical help during some stages of this project.
During the four years of operation, from 1965 to 1969, four different rings of pavements containing different base materials of varying thicknesses were tested. The results have been published in various reports, (1,2,3, and 4). Although the results have been partially analyzed, there has been no attempt to try to apply them to flexible pavement design. The overall purpose of this project is to try to apply the various results. The purpose of this report is to review all of the information collected during the design, construction, and testing of the first four rings and summarize the conclusions and recommendations made. Listed below are specific objectives of this study: