Performance Grade and Moisture-Induced Damage Potential of Chemically-Modified Asphalt Binders and Mixes

摘要

Among different Warm Mix Asphalt (WMA) technologies, chemical WMA additives are being widely used by the asphalt industry. In the present study, the effect of using two different types of chemical additives, referred to as CHM1 and CHM2, on the performance grade (PG) and moisture-induced damage potential of a PG 58-28 asphalt binder was evaluated. For this purpose, the asphalt binder was modified by adding 0.5% of CHM1 and CHM2. The dynamic shear rheometer, rotational viscometer and bending beam rheometer tests were conducted on binder blends to determine their PG and dynamic viscosity. The surface free energy (SFE) parameters of the binder blends were also determined in order to evaluate their moisture-induced damage potential with limestone and granite aggregates. Test results indicated that adding chemical additives to the asphalt binder did not significantly affect the high-temperature PG grade and dynamic viscosity of the asphalt binder. While the use of the chemical additives did not alter the PG grade of the asphalt binder, an increase of 3°C was observed in the low-temperature continuous grade of the binder blended with both additives. Based on the SFE results, it was found that binder blends without any additive and those containing CHM1 and CHM2 showed higher adhesion with granite aggregate than limestone aggregate. Therefore, it is expected that the asphalt mixes containing granite aggregate may exhibit a higher resistance to the moisture-induced damage potential than the one containing limestone aggregate.