This fall, the thickness of the aggregate surface layer will be measured and the cells will be resurfaced. The Superpave system, developed through the Strategic Highway Research Program, is believed to have the potential to improve the way these asphalt pavements are designed and constructed. Minnesota is in the process of evaluating that potential, with 2 sections placed in 1996, and 5 planned for 1997. In 1998, it is anticipated that all projects in Minnesota with over 3million ESALs will utilize Superpave. This is the first indication that Superpave will be cost effective.
Specific tests define binder characteristics in terms that are related to pavement distress.
The distress parameters used for evaluation of fatigue are low-temperature cracking and rutting. Software developed for Superpave enables engineers to analyze these relationships using material properties, climate, traffic, and pavement structure to predict pavement performance in terms of these distresses. This technology should enable highway agencies to select the type and proportions of materials needed to achieve a user-defined performance level that is within budget constraints. Existing concrete pavements that are cracked and deteriorating are normally overlaid with a hot mix asphalt layer to provide a smoother riding surface and protect the existing pavement structure. The problem with this practice is that over time, the cracks in the underlying concrete layer can reflect up through the new surface.