Effects of Moisture on Rheological Properties of PAV Aged Asphalt Binders

For the most coastal areas where the air is very humid, study on the effect of humidity on the performance of asphalt has its practical significance. However, limited research has been done to investigate the effect of humidity on rheo- logical properties of asphalt. In this study, asphalt binders were aged in the pressure aging vessel (PAV) under different con- ditions of moisture and aging time. Then Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) measure- ments were conducted to obtain the parameters relating to the complex modulus, phase angle, failure temperature, and creep stiffness. It was found that the low temperature performance decreased as evidenced by the results of the creep stiffness. While there were no significant differences among conditioned binders based on complex modulus G* and phase angle δ, it was found that the δ value increased when the humidity increased from 0% to 80%, and then the δ value decreased when the humidity increased to 100%. In addition, the results of the failure temperature indicated that the humidity of 80% would be a critical point for the high temperature performance of the asphalt binders. (1-3) . In this study, rheological properties of asphalt after PAV aging in the presence of 0%, 80%, and 100% moisture, respectively,