Evaluation of Rutting Resistance in Warm-Mix Asphalts Containing Moist Aggregate

Abstract

In recent years, rising energy prices and more stringent environmental regulations have resulted in an interest in warm-mix asphalt (WMA) technologies to decrease the energy consumption and emissions associated with conventional hot-mix asphalt production. In this study, the objective was to conduct a laboratory investigation of rutting resistance in WMA mixtures containing moist aggregates. Rut depth, weight loss, and gyration number of dry and conditioned specimens were measured for all of the mixtures. The experimental design included two aggregate moisture contents (0% and ∼0.5% by weight of the dry mass of the aggregate), two lime contents (1% and 2% lime by weight of dry aggregate), three WMA additives (Aspha-min, Sasobit, and Evotherm), and three aggregate sources. Thirty-six mixtures were prepared, and 216 specimens were tested in this study. Test results indicated that the aggregate source significantly affects the rutting resistance regardless of the WMA additive, lime content, and moisture content. In addition, rut depth of the mixture containing moist aggregate generally satisfies the demand of pavement performance without additional treatment. The mixture with Sasobit additive exhibited the best rutting resistance. The mixtures containing Aspha-min and Evotherm additives generally showed a rut resistance similar to that of the control mixture.