Hot-mix asphalt mixtures for Nevada's intersections

The overall objective of this research was to identify a hot-mix asphalt (HMA) mixture with good resistance to rutting and shoving at intersections to be used in the southern part of the state of Nevada. For that purpose, two laboratory evaluations were conducted: (a) evaluation of mixtures from in-service intersections and (b) laboratory evaluation of mixtures with different aggregate gradations. In the first part, field cores from 13 different projects cut from rutted and nonrutted intersections in southern Nevada were investigated in the laboratory to evaluate and compare the volumetric and gradation properties of the mixtures. In the second part, five aggregate gradations were selected for laboratory evaluation on the basis of past performance and results from the first part of this study. On the basis of the analysis of the data generated in this study, the aggregate gradation from the intersections that experienced no rutting showed the best performance in all the permanent deformation tests conducted in this experiment. In addition, the specifications used by the Nevada Department of Transportation for various permanent deformation tests were reviewed, and adjustments have been suggested for the HMA mixtures that are to be used at intersections. Interpretations from dynamic mechanistic analyses of pavements under heavy loads at intersections (with and without interface shear stresses) and laboratory behavior of HMA mixtures were used to arrive at these recommendations.