Moisture-induced damage potential of asphalt mixes containing polyphosphoric acid and antistripping agent

This study examines the effects of PPA and ASA on interfacial energies and moisture-induced damage potential of mixes using a Surface Free Energy (SFE) method. The SFE components of binder blends containing different amounts of PPA and ASA and aggregates were determined using Dynamic Wilhelmy Plate and Universal Sorption Device-based tests, respectively. Based on the measured SFE components and interfacial energy, it was found that using PPA with or without ASA does not affect cohesive bond of binder. However, depending on aggregate type, PPA may improve adhesive bond. Also, using an amine-based ASA does not improve the resistance to moisture-induced damage of binders or mixes containing PPA. Therefore, using an amine-based ASA with PPA-modified asphalt binder is not recommended. Among different PPA amounts considered, using 1.5% PPA with and without ASA was found to be the most effective concentration in improving the adhesive bond and wettability of binders with aggregates.