Development of a Gyratory Stability Index to Evaluate Variation of RAP Content and Rutting Resistance of Asphalt Mixtures

This project seeks to develop a modified mathematical algorithm for Gyratory Stability (GS) index applicable to the Pine Gyratory compactor with model AFG2AS which is being used at all ITD district, field, and central labs. The GS index can then be used to evaluate the resistance of hot mix asphalt (HMA) mixtures to rutting during the mixture design stage. Researchers will also examine the sensitivity of this index to the reclaimed asphalt pavement (RAP) content in asphalt mixtures. If found sensitive, the GS index can then be used as a quick indirect indicator of variation of RAP content in asphalt mixtures when placed in the field and as a tool to determine if the RAP content in a given mixture exceeds the allowable percentage. The study will investigate the applicability and sensitivity of American Association of State Highway and Transportation Officials (AASHTO) T 283, Lottman procedure, as a quality control tool during asphalt mixture production in the field.