Superpave construction issues and early performance evaluation

Many states have begun to construct a large number of Superpave mixes and by the year 2000 it is expected that most states will have adopted the Superpave technology as standard practice. This report outlines construction issues that have been identified by contractors working with Superpave mixes. The report also provides results of a national performance survey of Superpave mixes. There has been much talk about construction issues relating to Superpave. As a result the Federal Highway Administration (FHWA) and the National Asphalt Pavement Association (NAPA) jointly sponsored a meeting of experts to develop Superpave construction guidelines which were published in NAPA report number SR-180. As a follow-up to this publication NAPA and the State Asphalt Pavement Associations (SAPA) developed a survey for contractor personnel to develop a better understanding of construction problems with Superpave. This report includes a summary of the responses from this survey. Generally construction problems were identified but these problems were not significantly more difficult than construction problems with conventional mixes. Superpave is a new mix type and there are no long-term performance data. However, it is important that the Superpave performance be evaluated as more and more projects are constructed to measure performance and to determine possible changes in the Superpave process to improve performance. This report summarizes the results of the survey conducted in eight states (Arizona, Colorado, Florida, Indiana, Maryland, New York, Virginia, and Wisconsin). The performance to date has been good but most pavements inspected were only 1-2 years old.