Improved Resistance of Long-Term Aged Warm-Mix Asphalt to Moisture Damage Containing Moist Aggregates

Due to the use of many warm-mix-asphalt (WMA) additives in the market, the effect of long-term aging on these WMA mixtures is generally unclear; hence, it is necessary to simulate their performance in the laboratory. The objective of this study was to investigate the influence of various WMA additives on the moisture susceptibility of mixtures containing moist aggregates following a long-term aging process. Mass loss (percentage), indirect tensile strength (ITS) of dry and conditioned specimens, deformation (flow), and dissipated energy values were measured. The experimental design included two aggregate moisture contents (0% and approximately 0.5% by weight of the dry mass of the aggregate), two lime contents (1 and 2% lime by weight of dry aggregate), one liquid antistripping agent (ASA), five WMA additives, and two aggregate sources. A common long-term aging procedure was used in this study. The test results indicated that long-term aging improved the moisture resistance of WMA mixtures regardless of WMA additive, ASA, and moisture content. In addition, aggregate source affected the moisture resistance regardless of WMA additive, ASA, and aggregate moisture content. The effects of various WMA additives on the dissipated fracture energy of unaged mixtures are generally similar except that mixtures with Asphamin have relatively lower dry dissipated fracture energy. In addition, the aggregate type affected the dissipated energy value of WMA mixtures regardless of aging states. DOI: 10.1061/(ASCE)MT.1943-5533.0000567. © 2013 American Society of Civil Engineers. CE Database subject headings: Asphalts; Damage; Aggregates; Aging (material); Moisture. Author keywords: Warm-mix asphalt; Additive; Aging; Indirect tensile strength; Deformation; Dissipated energy.