Laboratory and Field Evaluation of Florida Mixtures at the 2012 National Center for Asphalt Technology Pavement Test Track

Abstract

The Florida Department of Transportation recently conducted a study at the National Center for Asphalt Technology Pavement test track to study cracking potential in asphalt mixtures. While cracking was the primary objective, the Florida Department of Transportation also wanted to ensure that no rutting would occur. Four mixtures were placed in test sections 100 ft in length. The four mixtures included two virgin mixtures: one used a polymer-modified binder and the other used a hybrid ground tire rubber and polymer-modified binder. The two other mixtures used combinations of polymer-modified binder with reclaimed asphalt pavement (RAP) or recycled asphalt shingles (RAS) or both. Conventional laboratory testing for rutting and cracking was performed on each mixture. In addition to the laboratory testing, field performance was assessed for rutting, cracking, and ride quality. Laboratory correlations were developed with field performance; however, because of the rapid crack propagation in the RAP–RAS test section, the correlations between 5 and 10 million equivalent single-axle loads (ESALs) changed significantly. The best correlations were developed between the resilient modulus of the mixture and cracking at 5 million ESALs and also the dissipated creep strain energy of the mixtures and cracking at 10 million ESALs. Overall, none of the mixtures experienced severe cracking in 10 million ESALs of trafficking.