One of the first applications of Superpave technology in Colorado was at a high traffic intersection near Denver in 1994. The project was developed to demonstrate whether Superpave asphalt technology could solve a recurring problem of rutting in a very severe traffic environment. Although the project was designed for an anticipated 8 million ESALs, recent traffic classification analysis indicates traffic is over 30 million ESALs in 20 years. In spite of this significant difference the Superpave asphalt materials are performing well. However, as would be expected, the control section developed ruts in the wheelpaths six months after construction.
The Superpave concept originally included both a mixture design method and an analysis system which was intended to determine the adequacy of the materials with respect to rutting and cracking distress. However, when this project was conceived and built, the analysis portion of Superpave had not been fully developed. Therefore, in the absence of a means to evaluate the structural ability of the design mixture by Superpave methods, the French Rut Tester and Hamburg Wheel Tracking Device were used to determine the adequacy of the design and construction mixtures. Analysis of results indicates field performance of asphalt mixtures may be predictable with respect to rutting.
This paper documents the planning, design, construction and two year performance of this very high traffic asphalt concrete intersection.