SUPERPAVE AND AGGREGATE PROPERTIES: WHERE DID THEY COME FROM AND WHERE ARE THEY GOING?

摘要

Aggregates are the major components of hot-mix asphalt. The quality of the aggregates is critical to the performance of the asphalt mixes and therefore a critical component of the Superpave design system. Aggregates make up 80 to 85% of the mixture by volume. Aggregate characteristics are a major factor in the performance of an asphalt mixture. In the Superpave mixture design system, many aggregate criteria were included to assure the performance of the asphalt mix. These criteria included coarse aggregate angularity (CAA), uncompacted voids in fine aggregate or fine aggregate angularity (FAA), flat and elongated particles, clay content, and gradation parameters. The recommended limits set by SHRP on these aggregate criteria were established by consensus of a group of experts based on years of previous research and experience. There is a great deal of work underway to refine and validate the existing Superpave aggregate requirements. The National Cooperative Research Program, Federal Highway Administration, and the state Departments of Transportation are all working on filling the gaps and improving the way we specify, design, and build our asphalt pavements. Superpave is only the beginning, not the end, of our road to true performance based design and construction specifications. Superpave has put us well ahead on that road, but there will always be things to improve on.