The new study defines the key parameters involved in analyzing the structural (thickness) and material (stiffness and type of subgrade) properties of pavements. The mathematical model is therefore based on the actual mechanical behavior of pavements under load. To obtain their results, Ulm and Akbarian fed their model data on 5,643 representative sections of the nation's roadways taken from Federal Highway Administration data sets. These data include information on the surface and subsurface materials of pavements and the soils beneath, as well as the number, type and weight of vehicles using the roads. The researchers also calculated and incorporated the contact area of vehicle tires with the pavement.
Ulm and Akbarian estimate that the combined effects of road roughness and deflection are responsible for an annual average extra fuel consumption of 7,000 to 9,000 gallons per lane-mile on high-volume roads (not including the most heavily traveled roads) in the 8.5 million lane-miles making up the U.S. roadway network. They say that up to 80 percent of that extra fuel consumption, in excess of the vehicles' normal fuel use, could be reduced through improvements in the basic properties of the asphalt, concrete and other materials used to build the roads.
"We're wasting fuel unnecessarily because pavement design has been based solely on minimizing initial costs more than performance how well the pavement holds up when it sh
|Contact: Denise Brehm|
Massachusetts Institute of Technology