Influence of Antistripping Additives on Moisture Susceptibility of Warm Mix Asphalt Mixtures

Abstract

Rising energy prices, global warming, and more stringent environmental regulations have resulted in an interest in warm mix asphalt (WMA) technologies as a means to decrease the energy consumption and emissions associated with conventional hot mix asphalt production. However, the utilization of the hydrated lime and liquid antistripping agents (ASA) in WMA mixture makes these issues more complicated. The objective of this study was to investigate and evaluate the moisture susceptibility of the mixtures containing ASA and WMA additives. The experimental design for this study included the utilizations of one binder source (PG 64-22), three ASA additives and control, two WMA additives and virgin, and three aggregate sources. A total of 36 types of mixtures and 216 specimens were fabricated and tested in this study. The performed properties include indirect tensile strength (ITS), tensile strength ratio (TSR), flow, and toughness. The results indicated that the hydrate lime exhibits the best moisture resistance for WMA mixtures, the liquid ASA additives can increase the ITS values of the mixtures but the liquid ASA generally exhibits a weak moisture resistance compared to the hydrate lime regardless of WMA and aggregate types in this study. In addition, the wet ITS values of mixtures containing WMA additives were lower than that of the mixtures without WMA additives.