Influence of Aggregate, Binder, and Warm-Mix Additive Interaction on Moisture Resistance of Asphalt Mixtures

摘要

Warm mix asphalt (WMA) refers to a set of technologies used to produce asphaltmixtures at a lower production temperature of the typical hot mix asphalt (HMA). Despite theenergy and environmental benefits of WMA mixes, the low production temperature may lead toresidual moisture in the aggregates as a result of incomplete drying. This residual moisture, ifsignificant, can jeopardize the mixture resistance to moisture damage. In this paper, the influenceof asphalt binder grade, aggregate source and warm-mix additives and their interaction on themoisture susceptibility of WMA mixtures was evaluated using the indirect tensile strength (ITS)and the dynamic modulus (|E*|) tests. The testing consisted of evaluating different WMAmixtures at the dry (i.e. undamaged) and moisture-damaged conditions after multiple freeze-thaw(F-T) cycling. Both ITS and |E*| values showed consistent results for the moisture resistance ofthe mixes. Multiple F-T cycling produced the difference between WMA mixtures with differentWMA additive. For the evaluated mixtures, the WMA with pelletized surfactant (PS) additiveexhibited the best resistance to moisture damage followed by the WMA mixtures with thechemical additive (VR). In this study, the WMA mixtures with the water bearing additive (WB)exhibited the worst resistance to moisture damage.