Assessing Moisture Sensitivity of Rubberized Warm Mix Asphalt Mixtures Using the Surface Free Energy Method and Dynamic Water Pressure Tester

Abstract

Abstract This study attempts to understand the effect of Zy as an antistripping agent on the moisture resistance of rubberized warm mix asphalt (WMA) mixtures using the surface free energy (SFE) method and dynamic water pressure tester (DWPT). First, viscosity tests were performed to determine the reasonable mixing and compaction temperatures. Therefore, volumetric properties of asphalt mixtures with all binders compacted with the Superpave gyratory compaction (SGC) method were measured. Second, the effects of Zy on micromechanisms of moisture damage in the asphalt-aggregate interface were analyzed using the SFE method. Finally, moisture sensitivity of the rubberized WMA mixtures was evaluated by determining the tensile strength ratio (TSR) of warm rubberized mixtures. The TSR was determined by the DWPT, a newly developed moisture-conditioning machine, to better simulate realistic moisture conditioning within asphalt pavements. The results suggest that E3G does not play a significant role in reducing binder viscosity, especially at high temperatures. Results also demonstrate that the Zy agent does not impact the temperature reduction function of E3G. The Zy agent significantly decreases the moisture damage of rubberized WMA mixtures in both SFE and TSR results. These findings also show that the DWPT has significant potential as an effective laboratory tool for better simulation of actual moisture conditioning.